Author Topic: Need help fixing Deck Legend keyboard  (Read 8307 times)

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Offline berserkfan

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Need help fixing Deck Legend keyboard
« on: Thu, 11 September 2014, 23:06:04 »
new problem with ANOTHER Deck; old problem deleted to avoid confusion
« Last Edit: Thu, 25 September 2014, 08:28:01 by berserkfan »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #1 on: Fri, 12 September 2014, 08:52:42 »
Yeah looks like there is a break in the last column of the matrix.

I will answer this more thoroughly when I have time. Gotta run!

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #2 on: Fri, 12 September 2014, 11:17:25 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:28:32 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #3 on: Fri, 12 September 2014, 12:42:50 »
My problem is not being able to follow the PCB to figure out where is pin 37 (so that I might try reflowing the solder)

This should be it:

76932-0
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #4 on: Fri, 12 September 2014, 15:20:57 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:28:48 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #5 on: Fri, 12 September 2014, 17:12:22 »
Maybe the plate is causing a short somewhere ? Or there is debris betw. the PCB and the piggy-back controller board ? See if you can find the resistor array RN3 and check the soldering on pins 3 and 14.

No LED's working -- does that include the indicator LED's ? If so, something may be messing w/ U1. Else the LED power supply may have a problem (stuff around Q3 & Q4.) What LED's where not working originally ? May be worthwhile to follow their traces towards the power unit.
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Offline esoomenona

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Re: Need help fixing Deck Legend keyboard
« Reply #6 on: Fri, 12 September 2014, 18:53:28 »
Can you take a better picture of the area with the resistors and such?

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #7 on: Fri, 12 September 2014, 20:22:54 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:01 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #8 on: Sat, 13 September 2014, 03:11:36 »
Probably would try to verify the integrity of the traces from P37 to the switches w/ a DVM.
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #9 on: Sat, 13 September 2014, 07:14:10 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:10 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #10 on: Sat, 13 September 2014, 17:30:52 »
Yes.
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #11 on: Mon, 15 September 2014, 03:37:47 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:23 by berserkfan »
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Offline infiniti

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Re: Need help fixing Deck Legend keyboard
« Reply #12 on: Mon, 15 September 2014, 07:30:12 »
Having some difficulty tracing since the PCB is 2-sided and is covered by the switches and the plate. :(

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #13 on: Mon, 15 September 2014, 09:38:14 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:32 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #14 on: Mon, 15 September 2014, 11:44:19 »
There seems to be a problem betw. P37 and the switches (someone slipped w/ a screwdriver ?) -- follow the trace and try to narrow down the area where the discontinuity is.
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #15 on: Mon, 15 September 2014, 12:32:41 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:41 by berserkfan »
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Offline Neebio

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Re: Need help fixing Deck Legend keyboard
« Reply #16 on: Mon, 15 September 2014, 12:49:00 »
ok, I got a multimeter and tried to test for continuity. but I am doing something wrong clearly. Not a single switch had continuity!

Thinking that maybe it was because I was supposed to press down the switches, I tried again. Also no response for any switch on the keyboard.

Um, how am I supposed to conduct this test?

When I ordered a couple G80-11900 keyboards off ebay, one of them came with some keys that didn't work.  While the seller was awesome and sent me another working one, they didn't want the broken one back so I set out to fix it.  I approached the issue with my multi-meter in hand and went to work doing continuity tests to find if (and where) the traces were broken.  The problem with my keyboard ended up being that somebody really must have hammered down on the left side keys or something because the PCB had micro-fractures in it, breaking a couple traces.

Here's how I do trace continuity testing:

(Note, I don't have a picture of my keyboard's PCB, so I just found a random picture to use that was good enough to see the traces)

77127-0

Take your multi-meter and set it to continuity mode (it should beep or something if you touch the probes together).  Touch one probe to solder joint A, and follow the trace on the PCB until the next solder joint or pad.  Touch the other probe to this solder joint (solder joint B).  If your multi-meter indicates that you have continuity (by beeping or something), then the trace is good, you can move on.  Next try from joint B to joint C.  If it's good, move on.  If it isn't good, and your multi-meter indicates that you don't have continuity try these steps:

Reflow the joints.  If that doesn't work, replace the trace with a direct wire connection.  Get some thin insulated wire, cut and strip it to a length that will reach from one joint to the next, and solder the wire into each joint.  You've now effectively replaced the trace.  Try the continuity test again.

With my repair job on the G80-11900, I had to replace something like 7 traces, sometimes going from a switch all the way back to the controller, sometimes only from switch to switch.  Follow the traces, test from one pad to the next, and replace any that are broken.

Hope this helps,
Neebio
RK9000RE w/ Raindrop & DDR arrow keys
Cherry G80-11900LUMEU-2 w/ Red/Black SA keys

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #17 on: Mon, 15 September 2014, 14:47:15 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:29:58 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #18 on: Mon, 15 September 2014, 15:07:40 »
From the schematic it looks like the key-diodes connect to the column, so P37 (column 18) goes to a resistor (w/in a R-array) and then to the switches diodes which then connect to the switches. A few caveats: the switches will not appear interconnected because of the diodes (that's their point :) ) and you have to mind the polarity of the DVM -- try measuring betw. P37 and say the NENT key, both pins. If there's no continuity on either pin, turn the probes around and try again. Repeat for each switch on column 18.
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #19 on: Mon, 15 September 2014, 15:14:52 »
Thank you very much Neebio; you're an awesome help!

That said, the Deck is a double sided PCB and many of the traces just disappear. I'm also not sure what to look for. I found a lot of discontinuity between (working) switches in the same row or column or with the same header (Eg D-something). So I know I"m not approaching it the right way.

Your experience suggests I may have lots of micro fractures on the Deck Legend that were caused in transit. No clear break or damage, but basically the keys on this column *-+Enter9 don't seem to be connecting to each other. But before I start wiring everything, I need to understand what this is all about. I can't read my keyboard's PCB, so I'm kind of doing things randomly. I don't know what is supposed to lead where.

Do you have any online resource about reading PCB traces? (I've started reading Komar007's thread on PCB design in hopes of learning a thing or two.)

When you are doing continuity testing, and you dont get continuity where you should, try swapping the DMM leads. You will only get continuity in one direction on a diode, and some DMMs will not give you anything useful at all. If you are measuring continuity across a diode, put your DMM in diode mode (if it has one) and you will read something like 0.5 Vf on a "good" diode and nothing if it's reversed. on a "bad" diode or joint, you will not read anything in either direction.

The column should go from one pin on the switch all the way back to the controller.

Based on your picture of the back of the PCB numberpad area, it looks like the columns are wired through diodes to the left pin on the switch, but it's hard to tell.

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #20 on: Mon, 15 September 2014, 16:26:23 »
old problem solved thanks everyone!

this part is not deleted just in case future people want to see it for reference, but it does not refer to the latest Deck problem

Since I don’t really know what is going on, I decided to look at the Deck Legend official schematic again.

It gives me the impression that Column 18 runs thus: * - 9 + Enter Del.
And that the rows are wired like this:
Pause *
/ -
8 9
6 +
3 Enter
0 Del

Would it be correct to say that every key in column 18 should have continuity with Pin37 because column 18 eventually leads to that pin on the master control unit?
And that they should have continuity with each other since they are in the same column?
And that Pause should have continuity with *, / with -, and so on since they are in the same rows?

I think right now the problem can be isolated.

I have found continuity in the rows
8 9
6 +
3 Enter
0 Del

No continuity in the two upper rows
Pause *
/ -
IE no continuity between Pause and *, and no continuity between / and -.

Deck’s schematics mention column 18 being led through RN3.C (resistor RN3.C?) but I don’t see any such resistor labeled on the PCB.

I also found no continuity between any member of column 18 with each other. However, I also tried the members of column 17, and there is no continuity between their members either, so I don’t know how it works.
« Last Edit: Thu, 25 September 2014, 08:31:28 by berserkfan »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #21 on: Mon, 15 September 2014, 16:52:59 »
Since I don’t really know what is going on, I decided to look at the Deck Legend official schematic again.

http://www.deckkeyboards.com/support/deck-legend-schematic

Oh my gosh, I didn't even know this existed> Yet another reason why TG3 is so awesome!

Looking through it now.

It gives me the impression that Column 18 runs thus: * - 9 + Enter Del.
And that the rows are wired like this:
Pause *
/ -
8 9
6 +
3 Enter
0 Del
You can see the entire matrix in this image (from the manual, first page).

so
/- are in row2
8 9 row 3
6+ row4
3 enter row5
0 del row6

It has a very compact matrix, with only a few unused locations.

Would it be correct to say that every key in column 18 should have continuity with Pin37 because column 18 eventually leads to that pin on the master control unit?
No, and for a few reasons.
First of all, every key has two pins on it. one of those pins connects to the columns via a diode. The other connects to the rows (no diode). This means that one pin of all the switches in a row are all connected and you can trace that connection all the way to the controller. For the colums, one side of the diode is conencted all the way to the controller, and one pin on each switch is connected through the diode to the controller, so that each switch has only one diode between it and the controller. You can verify this by putting your DMM in diodes mode and putting one lead on the correct pin on the controller, and the other on the proper side of the switch (or either side of the switch if it is pressed). You will get a Vf of ~.5V showing that there is one diode.

You can also verify this by looking at the schematic on pgs 2&3. You can see a clearer example of this by looking at backspace and = on the top right of page2. There is the switch pin, then a diode, then a common line running to col13 directly to the controller. Notice they are in different rows.

Deck’s schematics mention column 18 being led through RN3.C (resistor RN3.C?) but I don’t see any such resistor labeled on the PCB.

I also found no continuity between any member of column 18 with each other. However, I also tried the members of column 17, and there is no continuity between their members either, so I don’t know how it works.
THose are part of a resistor network (labelled RN on the PCB) you can see those as just a row of resistors soldered and labelled RN1 RN2 and RN3 in your pictures in the post above.

Pin # 37 is for col. 18, so there is a break somewhere between the controller pin and the switches. It could be the solder point grendel mentioned, or somewhere on the PCB (requires desoldering the entire thing) or somewhere on the controller daughterboard

If its the first one, you can likely fix with a jumper wire without desodlering. If it's the second, you will have to do more drastic measures (desodler that daughterboard and repair trace or reflow pin there?) Hard to say.

With your DMM in continuity mode, is there continuity between the pin#37 and the other end of the diode (square pad) near switch. If you try this on working rows you should hear a beep, and can use this to recognizer which diode is paired with what switch (they are mixed around a little to make room for holes in the PCB and other features). On troublesome column 18 this may or may not be the case, but might help isolating the issue.

Also note: you might have to press hard on the pad. Sometimes you have to pierce a thin oxidation layer before it will read continuity.

Another option is to put DMM in diodes mode and measure from the left pin (closest to center of switch) to the square pad to make sure the diode is measuring properly, then measure from left pin to pin37.
« Last Edit: Mon, 15 September 2014, 17:22:45 by dorkvader »

Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #22 on: Mon, 15 September 2014, 17:50:26 »
dorkvader is way better explaining things than I am ! :)

Backtrack a little, since RN3 is made of discrete resistors (thus exposing RN3.C), establish continuity betw. P37 and RN3.C (both sides), then betw. RN3.C and column 18 switches. Very clever of TG to have the plate cutouts to access those RN's. Also check the solder-joints of RN3.C, a bad one would explain the col 18 failure.
« Last Edit: Mon, 15 September 2014, 17:59:47 by Grendel »
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #23 on: Fri, 19 September 2014, 14:24:55 »
old problem solved thanks everyone!

this part is not deleted just in case future people want to see it for reference, but it does not refer to the latest Deck problem

OK, I haven't been able to fix this despite reflowing the solder on pretty much anything that looks less than textbook perfect.

I really have no idea how to do the continuity part. Front and back of PCB confuses me and I don't know which one is RN3.C (I assumed it was the third one from the left?)

In the meantime two things intrigued me about the Deck and I wonder if they can shed some light.

1) I had two LEDs, one over the return key and the other over backspace, fail at the same time as column 18 went out of order. I didn't mention it earlier because I thought LEDs were wired up separately from keys. But my LED tester proved they are working fine! Is it possible that some failed LED resistor may be causing a short or problem somewhere? Or is the LED failure coincidental but not related?

2) I'd bought some slow blink LEDs (The kind that change color slowly). They start red by default and transition through various other colors. I put one into my Tipro. Tipro isn't a backlit keyboard, but it always has at least one light on (it's a layer indicator light showing I'm in layer 1, the default). OK, so this works in Tipro. The light is actually quite bright, despite the fact that it was a 3.2v led being placed into something made for red 2.2v leds.

 But when I installed the slow blink LEDs into my Deck, they all remained the same starting color, Red. This is definitely not a 3.2v thing, since my Deck accepts other colors of 3.2v. I wonder if this has anything to do with Deck's resistor network for LEDs.

Lastly, may I ask you trained folks, can I simply assume every trace is broken and connect all keys in column 18 all the way to the daughterboard controller with some standard hookup wire?

The reason is that I am totally not trained in electrical stuff. I can't figure out all this diode across stuff. It would be vastly easier for me to simply do the drudge work by physically wiring up each key. I would take 10 minutes to do this; much easier than all my fruitless attempts to coax the multimeter into saying something and scrutinizing all those tiny little lines on the PCB that I don't understand.

I can live without diodes for this (why would anyone press two keys on the numpad at the same time? How can anyone do calculations safely like this?) Is that ok? Or am I still supposed to use diodes when I connect the columns?

I don't quite know which pin to use because I can't actually follow the traces on the PCB. Please give me your advice, and I will try to have the Deck hooked up tomorrow and hopefully be able to avoid giving up and desoldering and selling the clear switches.
« Last Edit: Thu, 25 September 2014, 08:32:01 by berserkfan »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #24 on: Sat, 20 September 2014, 09:38:45 »
OK, I haven't been able to fix this despite reflowing the solder on pretty much anything that looks less than textbook perfect.
sounds like your issue is with a broken trace or controller
I really have no idea how to do the continuity part. Front and back of PCB confuses me and I don't know which one is RN3.C (I assumed it was the third one from the left?)
I made a graphic

diamonds are switches on col 18
red circle is known diode for col 18 switch
red diamond is known diode for col 18 switch
yellow is the same but for a few suspected diodes.

What to do?
1. in a perfectly working kb, put one lead on the diamond. put the other on pin 37 (I think its the circled one but not 100% sure) DMM is in diodes mode. If you get a Vf of about .5V then you have continuity. If not then you don't
2. alternatively DMM in resistor mode or continuity mode put one lead on known diode square pad and the other on another one. Should get low resistance (few ohms) or beep also try from square pad to pin 37.

You will need to find where the break is. You will have to "hunt around" for the diodes. They have a square pad. The devices with 2 round pads are LED resistors.

3. diode finding: same as #2, one lead on a pad connected to col 18 trace or pin 37. hunt around with the other lead on square pads. mark them when found.

It's hard because you can only see 1/2 of the traces. but that's how you can figure out where the rest of the traces are. This would have been a lot easier if I had taken pictures of the pcb on the one I desoldered.


In the meantime two things intrigued me about the Deck and I wonder if they can shed some light.

1) I had two LEDs, one over the return key and the other over backspace, fail at the same time as column 18 went out of order. I didn't mention it earlier because I thought LEDs were wired up separately from keys. But my LED tester proved they are working fine! Is it possible that some failed LED resistor may be causing a short or problem somewhere? Or is the LED failure coincidental but not related?
led matrix is separate from switch one. This is odd, I suspect controller issue? Otherwise a spill or something took them both out at once.
2) I'd bought some slow blink LEDs (The kind that change color slowly). They start red by default and transition through various other colors. I put one into my Tipro. Tipro isn't a backlit keyboard, but it always has at least one light on (it's a layer indicator light showing I'm in layer 1, the default). OK, so this works in Tipro. The light is actually quite bright, despite the fact that it was a 3.2v led being placed into something made for red 2.2v leds.

 But when I installed the slow blink LEDs into my Deck, they all remained the same starting color, Red. This is definitely not a 3.2v thing, since my Deck accepts other colors of 3.2v. I wonder if this has anything to do with Deck's resistor network for LEDs.
those are not for leds. Each LED has it's own through hole resistor on the PCB. It is also quite odd, I don't know what could cause that. What colour leds did the deck come with? it still could be a "3.2v thing". like maybe it can't power whatever chip changes colours or whatever.


Lastly, may I ask you trained folks, can I simply assume every trace is broken and connect all keys in column 18 all the way to the daughterboard controller with some standard hookup wire?

The reason is that I am totally not trained in electrical stuff. I can't figure out all this diode across stuff. It would be vastly easier for me to simply do the drudge work by physically wiring up each key. I would take 10 minutes to do this; much easier than all my fruitless attempts to coax the multimeter into saying something and scrutinizing all those tiny little lines on the PCB that I don't understand.

I can live without diodes for this (why would anyone press two keys on the numpad at the same time? How can anyone do calculations safely like this?) Is that ok? Or am I still supposed to use diodes when I connect the columns?

I don't quite know which pin to use because I can't actually follow the traces on the PCB. Please give me your advice, and I will try to have the Deck hooked up tomorrow and hopefully be able to avoid giving up and desoldering and selling the clear switches.
to direct wire:
 wire one end of diode to red diamond. Wire the other end of diode to a long piece of wire. Wire the end of that wire to pin 37.

Make sure diodes are facing the right way of course. You can check against the pcb.

I'm trying a blank kb again so please excuse my problems with language.
« Last Edit: Sat, 20 September 2014, 09:40:37 by dorkvader »

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #25 on: Sat, 20 September 2014, 12:20:43 »
old problem solved thanks everyone!

this part is not deleted just in case future people want to see it for reference, but it does not refer to the latest Deck problem

1)   Red to the Cherry MX lead closer to the mounting post of the switch ie Dorkvader’s Diamonds.
2)   Grendel’s pins are correctly identified. I tried with Column 17, pin 38 which should be beside 37.
3)   I got 742-743 on all the members of column 17. Don’t know what that means. According to my manual that’s the forward voltage drop in miliV but that means over 0.5v. Also continuity buzzer did not sound. Its supposed to sound right?
4)   When I depress a switch while testing, I find the other Cherry MX switch lead (the further one from the center mounting post) is also able to produce a similar voltage drop. But no continuity sound.
5)   Pin 37 to any of the diamonds, no response.
6)   Tried Pin 34, Row 5. Black to the controller, red to the further pin from the mounting post. After all, Rows should be reversed right? And there was response, albeit around 300 miliV. So I guess on average Rows and Columns have 0.5v?
7)   Black lead to Pin 34 and red to square pads of Row 5 gets a response.
8)   Black to Pin 38 and red to square pads of Column 17 gets a response
9)   Black to pin 37 and red to square pads of Column 18:
a.   B21 626 mV
b.   B20 1062
c.   C20 1063
d.   D17 1062
e.   F15 1065
f.   F14 656
10)   Continuity mode across square pad Diodes: square pads are columns, so one square pad to another should be in the same column. The other columns worked fine showing very tiny resistance under 1 ohm. But the square pad is not always on the same side of the switch, sometimes left sometimes right.
11)   Identifying the correct square pad was very hard for me. But I found that every member of Column 18 had low resistance between themselves. Between the top member of this column and pin 37 – no response. Bottom member of this column and pin 37, also no response.

Since I figured that the trace had to be broken somewhere between either the top switch or the bottom switch of the column and pin 37, I decided to try soldering in a bridging wire/diode. There is no way with my current level of (in)competence I can hope to identify where the trace is broken inside the PCB, scrape off the top layer and bridge the copper lead inside.

Am I right in looking at the Deck Schematic, that I should try soldering a diode/wire between the Del/F14 key and pin 37, because that’s how Deck expected Column 18 to be connected to the keyboard controller?

Then I looked at the diodes you sent me. They’re a bit hard to figure out although one ring seems bigger/ darker than the other/ others. I tested them on multimeter, and was amazed to find that using the ‘Diode’ setting, both ends of the diode got 455mV. That means essentially the diode flows 2 ways? Then I tried the resistance setting, and got no result. I am puzzled. Tried several diodes and they were the same.

I must be doing something wrong, but what? I placed the diode on different nonconducting surfaces: wood, glass and paper, before I pressed down my multimeter leads on the two ends of the diode. I can’t figure this out, except I’m determined to at least try the direct wiring thing.

Next, the LEDs.

I don’t really know how to read a schematic, but it doesn’t seem that the Enter and Backspace LEDs, despite being near each other, are anywhere near each other on the LED matrix. There is no visible damage when keycaps are removed, so if there’s a spill it can only be seen after I desolder the keyboard and expose the hidden side of this double sided PCB. I assure you I definitely tried the simple stuff such as reflowing solder; the leads of the LEDs were definitely firmly soldered to the pads.
« Last Edit: Thu, 25 September 2014, 08:32:36 by berserkfan »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #26 on: Sat, 20 September 2014, 12:38:56 »
3)   I got 742-743 on all the members of column 17. Don’t know what that means. According to my manual that’s the forward voltage drop in miliV but that means over 0.5v. Also continuity buzzer did not sound. Its supposed to sound right?
about right for diodes. I just measured about that. 0.7 or 0.75 is about average it seems. Some dmms continuity test will not work with a diode dropping all that voltage. It will depend.

will go over the rest if Ihave time. Today I need to wire up a floor plate lift motor

edit: some dmm on diode mode will try flowing both ways to see what vf the diode has. Diode does NOT flow current both ways (we hope) unless its broken.

you can verify this by connecting 2 diodes in opposite directions in series. Even in diode mode it shoudl show nothing as one of the didoes will block current and the other blocks it form othjer direciton.

will read over more. Hard to make sense of some of it so I will have to do some interpreting.
« Last Edit: Sat, 20 September 2014, 12:44:45 by dorkvader »

Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #27 on: Sat, 20 September 2014, 12:50:11 »
old problem solved thanks everyone!
« Last Edit: Thu, 25 September 2014, 08:32:56 by berserkfan »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #28 on: Sat, 20 September 2014, 15:29:56 »

will go over the rest if Ihave time. Today I need to wire up a floor plate lift motor

edit: some dmm on diode mode will try flowing both ways to see what vf the diode has. Diode does NOT flow current both ways (we hope) unless its broken.

will read over more. Hard to make sense of some of it so I will have to do some interpreting.

Floor plate lift motor? So you're working as an electrician now?

Don't worry about my notes; these were just to show that I tried comparing some other rows and columns with the results on my problemmatic column 18. To be scientific, we need controls for comparison.

I basically came to the conclusion that there's no problem between the different keys of column 18. So the problem lies between the last key in this column, and its connection to the keyboard controller. I have no explanation why there is higher mV between some keys though.

If the flaw lies in Deck's keyboard controller, I suppose I'll have to get a teensy with pins and replace the controller. But I may lose control of the LEDs.

I think I've figured out that you sent me resistors for LEDs not diodes for wiring up keyboards. OK, so I will need to buy diodes? Or can I swipe these from my Cherry Corp. keyboard switches (all of which have diodes)? There's no specification that I need to meet, right? Just open a switch, dig out the diode, and try wiring it up? That sounds much easier to me than staring at a PCB!

As for the resistors you sent me, they could come in real handy. Does it make sense to identify the resistors associated with backspace and return (which had 'dead' leds that were actually working), change these resistors? Or do you think the trace is also broken, meaning I should wire up these LEDs in some way?

For non-working LEDs do you think I can also wire them up like regular keyswitches? IE hook them up on the LED matrix and voila they come back to life without me having to trace the actual place where a copper trace would be broken?
nah it's our new lift. Dad and I are wiring it up. Lots of fun.

so if you can measure the same .74v diode from the pin37 to any switches, then the short has to lie elsewhere.

It may be possible to teensy it, you would have to wire all the rows and colums. LEDs are easy, just wire them all to one transistor and switch it on or off with the teensy. Hard part at that point is then finding code for teensy to control LED.

Going to a dinner now, sorry for delays, will give this another good once over when I have time.

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Re: Need help fixing Deck Legend keyboard
« Reply #29 on: Wed, 24 September 2014, 04:19:09 »
old problem solved thanks everyone!

« Last Edit: Thu, 25 September 2014, 08:33:13 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #30 on: Wed, 24 September 2014, 12:54:00 »
If no LED works (including the status indicators ?) something went wrong w/ the LED's power supply circuitry around U1.

Try to set the Deck into "status indicators always full bright" (FN+CAPS ? Q5 will then take over powering them), if they start working the problem is most likely around Q3/Q4. If they are still not working, the problem could be w/ U1 itself.
« Last Edit: Wed, 24 September 2014, 12:58:24 by Grendel »
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #31 on: Wed, 24 September 2014, 14:14:35 »
looking at the schematic, all the BL leds connect to BL_supply or BL_return. If either of those traces is damaged no backlights will work.

edit: good post by grendel again! What he says appears to be true. I would check that first.

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Re: Need help fixing Deck Legend keyboard
« Reply #32 on: Wed, 24 September 2014, 15:26:59 »
old problem solved thanks everyone!

« Last Edit: Thu, 25 September 2014, 08:33:30 by berserkfan »
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Re: Need help fixing Deck Legend keyboard
« Reply #33 on: Wed, 24 September 2014, 15:36:37 »
looking at the schematic, all the BL leds connect to BL_supply or BL_return. If either of those traces is damaged no backlights will work.

edit: good post by grendel again! What he says appears to be true. I would check that first.

looking at the schematic I don't see what Capslock connects to that the other leds don't. I guess the lock lights are connected differently? eg The backlighting for capslock, numlock keys also does not work, but the lock lights (located on the top right hand side of the kb) do work.

What is most interesting is that after Grendel's instruction to do fn+capslock, caps lock light is always able to work even after I press fn-0 (which on the Deck Legend shuts down all LEDs normally, INCLUDING the lock lights.)

This is very interesting. What next? I still believe that my incompetent soldering may have caused the problem, since originally all leds were working until after my SIP socket mod. One LED was not working so I tried reflowing the solder (SIP sockets are a bit too short to protrude above the PCB and maintaining contact is a problem). And after that, all leds except the lock lights stopped working. I am suspecting there is a short somewhere so how do I test for it? I did try to clean up my bad soldering with wick, but maybe there is a short hidden on the other side of the PCB?
« Last Edit: Wed, 24 September 2014, 16:07:42 by berserkfan »
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #34 on: Wed, 24 September 2014, 18:34:15 »
looking at the schematic I don't see what Capslock connects to that the other leds don't. I guess the lock lights are connected differently? eg The backlighting for capslock, numlock keys also does not work, but the lock lights (located on the top right hand side of the kb) do work.

In "daylight" mode (see below) the status LED's are powered by the current source around Q5 whereas in "normal" mode they draw power from the same source the backlight LED's do (current source around Q3 & Q4.) If the status indicators work in "daylight" mode, U1 is most likely fine. It's a serial-to-parallel shift register -- outputs Q0, Q1, and Q2 are used to turn the status LED's on and off, outputs Q3-7 determine the backlight level (in a pretty clever way actually, but I digress ;))

What is most interesting is that after Grendel's instruction to do fn+capslock, caps lock light is always able to work even after I press fn-0 (which on the Deck Legend shuts down all LEDs normally, INCLUDING the lock lights.)

From the Legend's manual:
Quote
The second mode is a “daylight” mode in which the status LEDs remain bright at all backlighting brightness levels  ‐ even if the backlighting is turned “off”.  Please note that the status LEDs will dim slightly as the backlighting levels decrease toward level 1.    The status LED mode is toggled by pressing “Fn” followed by “Caps Lock” key.  Just as with the dimming operation, no “Caps Lock” key information is sent to the PC when the “Fn” key is down.  If the non‐volatile memory fails, the default power‐on settings are level 7 brightness and the status LEDs dim along with the backlighting of the keys.

There is a caveat tho -- in the old Legend's (like your PCB but w/ the big chip instead of the small-to-big adapter board) this works as described. I got one last year w/ a redesigned PCB using all SMD parts (including the controller) and it didn't work as described: the state was stored in the flash but not applied at power-up, ie. it always came up w/ the "daylight" mode off and you had to hit Fn+CAPS twice to reactivate it. (Had to send my board back so TG could replace the controller w/ one that had fixed firmware..) Since you got the SMD type controller there's a chance that you see the buggy behavior w/ your Legend.

This is very interesting. What next? I still believe that my incompetent soldering may have caused the problem, since originally all leds were working until after my SIP socket mod. One LED was not working so I tried reflowing the solder (SIP sockets are a bit too short to protrude above the PCB and maintaining contact is a problem). And after that, all leds except the lock lights stopped working. I am suspecting there is a short somewhere so how do I test for it? I did try to clean up my bad soldering with wick, but maybe there is a short hidden on the other side of the PCB?

Well, if you SIP socketed all LED's and suspect a short on one or more of them you'll have to measure across each LED to find it. If they are all ok, try to find Q3 and Q4, identify the BL-SIGNAL, and start measuring things. LED's are not exactly wired straight forward, check the note at the bottom of the schematics 2nd page.
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #35 on: Thu, 25 September 2014, 01:30:22 »
Wow, the problem gets more and more complicated.

Firstly, I am now talking about a different Deck Legend. The first one has been fixed. I ran an ugly looking wire +diode from one key on column 18 to pin 37, thinking it was just a test, and everything worked so I decided not to test fate and hastily covered everything up and now that Deck is fully usable with no complaints. I didn't want to start a new thread. But I think I may delete the earlier posts and photos since this is a very specific problem and won't help many people.

This second Deck, is new and has your onboard controller rather than a daughterboard.

After a SIP mod, all keys worked. But numpad8 didn't light up, nearly all other LEDs were ok but a couple seemed to flicker or turned off/ turned on when I moved the keyboard or pressed the switch which made me suspect poor contact so I wanted to work on them also.

When I'd tried reflowing the solder to improve the contacts, that was when my troubles started. ALL non-lock light LEDs died and led to me asking for help.

Following you, Dorkvader and thechemist's advice I took a multimeter and set to continuity. I found all LEDs produced a number around 665 (miliamps?). Except one, numpad8, which was the led that won't light up in the first place. That produced a continuity beep.

So I totally desoldered that switch, wicked up all excess solder, opened it to make sure no irregularities inside such as SIP sockets connected by some debris, soldered the switch back in.

And then?

All switches continue to actuate fine. Lock lights were ok (I’d also took advantage of the moment to SIP mod the lock lights for fun.) But not a single keyboard led could produce the 665 number or any number anymore. The multimeter remained stuck stubbornly at 1.

Strangely, although almost no led lit up, numpad 8 did. Along with a small handful of orange LEDs. But very weakly, and no tinkering with the lighting controls could make them brighter or turn on the other LEDs.

Figuring that my Christmas tree lighting scheme (I’d put in a number of colors, mostly 3.3v but a few orange and yellow 2.2v LEDs) may add complications I removed all orange LEDs (which are 2.2v instead of the 3.3v that the board was built for). And now no leds work except for lock lights.


What should I do next?  :'( :-\ :-X
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #36 on: Thu, 25 September 2014, 08:23:03 »

MY latest attempt to fix things:

1)   Removed all LEDs from SIP sockets
2)   Tested all leds
3)   Found one burnt out and discarded it
4)   Kept away all 2.2v leds and only used 3.3v leds on this board
5)   Plugged in keyboard and straight away saw the spacebar lights, which are not wired to the switches, light up
6)   Started putting in green and noticed they were ok. I put in all my greens and they were lighted up but dim and the light function couldn’t make them brighter
7)   Decided that maybe when all leds were in, the board would be ok. Put in other leds. Found that only the green lighted up then when all leds were put in, board refused to light up. When I plugged in the green and spacebar leds would weakly light, then vanish. The magenta, blue, 3.3v rose red all never lighted. The lock lights remain as bright as ever. Turning up the led function settings had no effect.
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Offline Thechemist

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Re: Need help fixing Deck Legend keyboard
« Reply #37 on: Thu, 25 September 2014, 08:48:53 »
Did you try testing the voltage in each row, pick few leds in that row and take a reading. First try it with all leds in then try it with no leds.

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Re: Need help fixing Deck Legend keyboard
« Reply #38 on: Thu, 25 September 2014, 10:23:39 »
Did you try testing the voltage in each row, pick few leds in that row and take a reading. First try it with all leds in then try it with no leds.

how to do that? Do I do a voltage drop/ 200 ohms setting resistance test between the leads of each LED, and try doing that for the leds in each row of the LED matrix? Am I supposed to see voltage drop of 3.3v across one LED and also two leds (since they are wired up parallel?)

I don't quite know how to read the LED matrix on the Deck Legend schematic (from their website) but it seems largely the same as the keyboard matrix based on the lines BL-supply and LED-return. I also get the impression that two keys share the same resistor on average except spacebar which seems to share resistors with two keys (spacebar has two LEDs)
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Offline dorkvader

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Re: Need help fixing Deck Legend keyboard
« Reply #39 on: Thu, 25 September 2014, 14:55:09 »
trying to detect the "resistance" of an LED isn't really a useful measure. It sounds like your num8 LED failed in short so replacing it is crucial.

To measure LEDs try diode mode to measure the forward voltage drop. Volts mode might work too (especially if it's powered)

I actually can't find my DMM right now, I think Dad might have borrowed it again.

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Re: Need help fixing Deck Legend keyboard
« Reply #40 on: Thu, 25 September 2014, 15:04:48 »
trying to detect the "resistance" of an LED isn't really a useful measure. It sounds like your num8 LED failed in short so replacing it is crucial.

To measure LEDs try diode mode to measure the forward voltage drop. Volts mode might work too (especially if it's powered)

I actually can't find my DMM right now, I think Dad might have borrowed it again.

actually I've measured the voltage for every LED and was surprosed to find that apart from the fully functional lock lights, all other LEDs are 2.15v. Somehow this Deck now thinks it is a Deck Fire (the model with 2.2v red leds). I have no idea how that could be so, especlally when there's no Deck documentation on this.

However there are a few components on the Deck motherboard that seem to be governing the LED colors, marked R, Y, G, B respectively. Not sure how these work and Deck is ignoring support emails.
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #41 on: Thu, 25 September 2014, 15:06:42 »
Let me guess -- the 1st Deck was a Legend Ice (blue LED's) and the 2nd one is a Legend Fire (red LED's) ?

TG did a really great job designing the board to work w/ the LED's available at the time -- two switches share a LED/resistor network that is populated depending on the characteristics of the LED's used, mainly the forward voltage. For low forward voltage LED's (less than ~2.2V, red and yellow according to the schematic) only one resistor is used (R3A's) and all three components are wired in series. If the LED's require a greater forward voltage than 2.2V, all LED's connect to the current source w/ their own resistor (R3B's and R3G's.) This configuration is a lot more forgiving when driving LED's w/ different characteristics. For the former configuration you will have to find LED's w/ a low forward voltage (< 2V), LED's w/ greater voltages will simply stay dark...
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #42 on: Thu, 25 September 2014, 16:33:09 »
Let me guess -- the 1st Deck was a Legend Ice (blue LED's) and the 2nd one is a Legend Fire (red LED's) ?

TG did a really great job designing the board to work w/ the LED's available at the time -- two switches share a LED/resistor network that is populated depending on the characteristics of the LED's used, mainly the forward voltage. For low forward voltage LED's (less than ~2.2V, red and yellow according to the schematic) only one resistor is used (R3A's) and all three components are wired in series. If the LED's require a greater forward voltage than 2.2V, all LED's connect to the current source w/ their own resistor (R3B's and R3G's.) This configuration is a lot more forgiving when driving LED's w/ different characteristics. For the former configuration you will have to find LED's w/ a low forward voltage (< 2V), LED's w/ greater voltages will simply stay dark...

NO NO NO
 NO!

Both Decks are 3.3v. There is no reason why they would not have been able to support higher voltages.

This one is a Deck Frost that I removed my clear LEDs from. In any case as I said, the multi colors were working fine for days until I tried to repair the only dead led+ 2 seemingly weak solder joints and then things went down suddenly without me having touched anything else at all.

That's why I am so puzzled that things went down to 2.2v. I don't understand how the electricity worked, but I can see there are 4 resistors at the top left supposedly governing whether this is a Deck Ice, Fire, Frost, Toxic and I am wondering if these things can fail and cause the Deck to be bumped down to a lower voltage. After all surely it is not possible that all resistors for individual leds will fail at the same time so it has to be something further upstream or at some bottleneck that all signals pass through.
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #43 on: Thu, 25 September 2014, 17:10:02 »
NO NO NO
 NO!

Both Decks are 3.3v. There is no reason why they would not have been able to support higher voltages.

This one is a Deck Frost that I removed my clear LEDs from. In any case as I said, the multi colors were working fine for days until I tried to repair the only dead led+ 2 seemingly weak solder joints and then things went down suddenly without me having touched anything else at all.

That's why I am so puzzled that things went down to 2.2v. I don't understand how the electricity worked, but I can see there are 4 resistors at the top left supposedly governing whether this is a Deck Ice, Fire, Frost, Toxic and I am wondering if these things can fail and cause the Deck to be bumped down to a lower voltage. After all surely it is not possible that all resistors for individual leds will fail at the same time so it has to be something further upstream or at some bottleneck that all signals pass through.

My bad, too much skimming. You can actually see some missing R3A resistors in your pics :) Other possibilities I can think of (take it w/ grain of salt..) are a damaged current source (maybe Q3 and/or Q4 shot) (*) or another short somewhere that drains enough current to cause the voltage to collapse (altho I would sort of expect the PC the board is connected to complain about too much current draw on the port in this case...)

(*) using a 2.2V LED where the design asks for 3.3V will cause the current draw to rise (voltage drop over the resistor increases --> ++current.) If you used enough of them you may have stressed the current source beyond of what its components can handle.

BTW, the board I had to return to TG for a controller replacement was the exact same board -- a Legend Frost w/ the controller marked "WG 01/06/12 CS: D30B". :/
« Last Edit: Thu, 25 September 2014, 17:21:49 by Grendel »
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #44 on: Fri, 26 September 2014, 04:29:58 »
NO NO NO
 NO!

Both Decks are 3.3v. There is no reason why they would not have been able to support higher voltages.

This one is a Deck Frost that I removed my clear LEDs from. In any case as I said, the multi colors were working fine for days until I tried to repair the only dead led+ 2 seemingly weak solder joints and then things went down suddenly without me having touched anything else at all.

That's why I am so puzzled that things went down to 2.2v. I don't understand how the electricity worked, but I can see there are 4 resistors at the top left supposedly governing whether this is a Deck Ice, Fire, Frost, Toxic and I am wondering if these things can fail and cause the Deck to be bumped down to a lower voltage. After all surely it is not possible that all resistors for individual leds will fail at the same time so it has to be something further upstream or at some bottleneck that all signals pass through.

My bad, too much skimming. You can actually see some missing R3A resistors in your pics :) Other possibilities I can think of (take it w/ grain of salt..) are a damaged current source (maybe Q3 and/or Q4 shot) (*) or another short somewhere that drains enough current to cause the voltage to collapse (altho I would sort of expect the PC the board is connected to complain about too much current draw on the port in this case...)

(*) using a 2.2V LED where the design asks for 3.3V will cause the current draw to rise (voltage drop over the resistor increases --> ++current.) If you used enough of them you may have stressed the current source beyond of what its components can handle.

BTW, the board I had to return to TG for a controller replacement was the exact same board -- a Legend Frost w/ the controller marked "WG 01/06/12 CS: D30B". :/
This is proving a nightmare!

Now I'm down to thechemist, who has been patiently giving me instructions (test this, leads on x and y, set multimeter to z). Hopefully sooner or later the culprit resistor can be found. Because I really don't want to be using this as a crappy 2.2v led board with only red, orange and yellow to choose from.
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #45 on: Sat, 27 September 2014, 08:34:33 »
Help!

Remember my Deck Legend 3.3v had been mysteriously bumped down to 2.15v (the current that flowed across every single led except for the lock lights)? I decided to change every LED to a 2.2v one to see if they would work – and now none work. Even the lock lights no longer respond to the day function. All leds down. There was no soldering done in the meantime since they are all SIP sockets. Keyboard is placed on wood. I see no reason for the short.

This is terrible. I will never buy a Deck again. By this point I am less blaming my own incompetence, and more blaming people who design something so fragile and easily screwed up. Seems as though you can kill a Deck very easily in comparison with other keyboards.
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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #46 on: Sat, 27 September 2014, 17:49:03 »
Well, it was never designed to swap LED's :P I don't think it's screwed up more easily than any other keyboard with this level of complexity. As for the lock-LED's, remember the bug I described -- did you try hitting Fn-CAPS twice after power on ?
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #47 on: Sat, 27 September 2014, 20:32:25 »
Well, it was never designed to swap LED's :P I don't think it's screwed up more easily than any other keyboard with this level of complexity. As for the lock-LED's, remember the bug I described -- did you try hitting Fn-CAPS twice after power on ?

Yes I did.

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Offline Grendel

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Re: Need help fixing Deck Legend keyboard
« Reply #48 on: Sun, 28 September 2014, 02:38:54 »
Sorry man, I'm running out of ideas. I'm sure it's the current source, but my knowledge of analog electronics is fairly limited. :( Have to pass the buck to the EE's reading this.
Currently using: RK-9000WH/GR, CMS QFXT w/ Ghost Squid
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Offline berserkfan

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Re: Need help fixing Deck Legend keyboard
« Reply #49 on: Tue, 30 September 2014, 07:53:13 »
Sorry man, I'm running out of ideas. I'm sure it's the current source, but my knowledge of analog electronics is fairly limited. :( Have to pass the buck to the EE's reading this.

Thanks a lot for all that you've done; it's plenty educational for me!
Most of the modding can be done on your own once you break through the psychological barriers.