Post by: m3741 on Mon, 17 December 2018, 09:50:33
I found an old IBM M2 of mine in my grampa's attic; Its cord is missing, but overall all pieces are there.
I'm working on restoring it and have already replaced the capacitors [which were most likely dead].
All I need to get this bad boy working again is to know where which of the pins in the PCB go to in the ps/2 plug.
Could any one of you fine lads tell me which is the Ground, Clock, Data and 5v pins?
Here is a picture of me holding my keyboard's PCB:
(http://i2.photobucket.com/albums/y13/m3741/bb34d52d-3e10-46a5-ad27-9bfa9e2a2ed1.jpg) (http://s2.photobucket.com/user/m3741/media/bb34d52d-3e10-46a5-ad27-9bfa9e2a2ed1.jpg.html)
Here is the plug I have that goes into the PCB:
(http://i2.photobucket.com/albums/y13/m3741/Seleccedilatildeo_098.png) (http://s2.photobucket.com/user/m3741/media/Seleccedilatildeo_098.png.html)
I'm inclined to believe that red is 5v, black is ground, yellow is clock and white is data, but I don't want to take any chances and fry my only board.
I appreciate you help!
Thanks a lot!
Post by: Tactile on Mon, 17 December 2018, 11:52:44
Post by: m3741 on Mon, 17 December 2018, 12:11:26
Any how, thank you very much for your reply, now my quest has narrowed down to just figuring out if the red and black wires are respectively, 5v and ground.
Post by: ErgoMacros on Mon, 17 December 2018, 13:03:29
Post by: fohat.digs on Mon, 17 December 2018, 17:39:14
Post by: m3741 on Mon, 17 December 2018, 18:00:58
Well, I guess I'm back to square one on this again... Better safe than sorry.
Post by: m3741 on Tue, 18 December 2018, 09:33:21
Post by: Snowdog993 on Tue, 18 December 2018, 10:13:34
Blk - GND
Wht - CLk
Yel - Data
Like it helps....
Post by: m3741 on Tue, 18 December 2018, 16:08:35
No one wants more than I do for this to be 100% accurate.
Are you 100% sure on this, do you own the same keyboard?
I mean, can I bet my single board on this info?
Please don't get me wrong, I'm in no way doubting your intentions in helping me out on this issue. My skepticism mainly comes from the earlier post regarding another IBM keyboard model whose wire colors were completely different.
Post by: Snowdog993 on Tue, 18 December 2018, 20:06:23
EDIT:
I would verify with another M2 if I had one. But I don't and the best solution I see is to actually compare a working M2 keyboard with the connector. There are a lot of different wiring diagrams for the IBM Model M and M2. The Lexmark chipset may or may not correspond to the actual pinouts.
This is a guess on my part. I can't verify it so I can't say it's accurate.
Post by: Snowdog993 on Tue, 18 December 2018, 20:28:22
Fohat is correct in telling you to not trust the colors but the pinouts could very well match/not match. I spent some time looking at my resources and couldn't find anything pertaining to the M2. Sorry about that. All I did was guess.
Post by: invariance on Wed, 19 December 2018, 14:49:38
Sent from my iPhone using Tapatalk
Post by: m3741 on Thu, 20 December 2018, 09:52:13
Post by: m3741 on Thu, 20 December 2018, 13:00:36
I noticed that one of the pins runs a very long trail all across the board and this trail goes through all positive poles of the leds (caps, num and scroll). So, without shadow of doubt that's the +5v pin, as we all know LEDs have a specific polarity to work.
It also turns out that this keyboard seems to follow the color scheme fohat.digs sent, as this pin is the one connected to the black wire.
Using a multimeter I was able to determine the ground pin, as it is the pin combination that gives less resistance.
That was another indication that this keyboard seems to follow the color scheme fohat.digs sent, as this pin is the one connected to the white wire.
As Tactile pointed out, mixing clock and data is not harmful, so, given that +5v and GND are folloqing fohat.digs' color scheme, I'll wire them up accordingly and I'll post the results here.
Wish me luck!!!
So far, thank you all very much!
Post by: m3741 on Fri, 21 December 2018, 12:26:24
(https://i2.photobucket.com/albums/y13/m3741/videotogif_2018.12.21_16.37.59.gif) (https://s2.photobucket.com/user/m3741/media/videotogif_2018.12.21_16.37.59.gif.html)
Results: Keyboard doesn't work.
I'm sure +5v and ground are wired correctly as otherwise the LEDs wouldn't turn on.
I've seen online that usually when that happens the capacitors on the board are dead, but I changed the capacitors on the board for brand new electrolytic capacitors (as you can see) with the same uf and voltage of the original ones.
I also tried switching the Data and Clock cables around, but no luck.
On Linux, kernel messages when I plug the keyboard to a USB port show:
Code: [Select]
[ 2015.119629] usb 2-2: new full-speed USB device number 38 using xhci_hcd
[ 2015.247696] usb 2-2: device descriptor read/64, error -71
[ 2015.483718] usb 2-2: device descriptor read/64, error -71
[ 2015.719621] usb 2-2: new full-speed USB device number 39 using xhci_hcd
[ 2015.847683] usb 2-2: device descriptor read/64, error -71
[ 2016.083646] usb 2-2: device descriptor read/64, error -71
[ 2016.191652] usb usb2-port2: attempt power cycle
[ 2016.843601] usb 2-2: new full-speed USB device number 40 using xhci_hcd
[ 2016.843920] usb 2-2: Device not responding to setup address.
[ 2017.051940] usb 2-2: Device not responding to setup address.
[ 2017.259586] usb 2-2: device not accepting address 40, error -71
[ 2017.387592] usb 2-2: new full-speed USB device number 41 using xhci_hcd
[ 2017.387909] usb 2-2: Device not responding to setup address.
[ 2017.595889] usb 2-2: Device not responding to setup address.
[ 2017.803569] usb 2-2: device not accepting address 41, error -71
[ 2017.804601] usb usb2-port2: unable to enumerate USB deviceAny advice?
Tried two types of PS/2 adapters, those tiny converters that all they do is rewire the PS/2 wires to the USB and also tried the kind that have a circuit board in them and have two entries, one for PS/2 keyboard and another one for mouse.
None of them worked...
Post by: rich1051414 on Sat, 22 December 2018, 02:20:37
IBM was never consistent, and NEVER TRUST COLOR but this is the scheme for the Model F 122-key terminal:I cannot stress enough how you should NEVER trust wire colors on IBM keyboards. In the past I have accidentally read a female diagram as a male, and since the colors agreed, I just accepted that. BIG MISTAKE. Totally ignore the colors entirely, no matter how much it makes you question it.
Post by: fohat.digs on Sat, 22 December 2018, 08:21:01
I have accidentally read a female diagram as a male, and since the colors agreed, I just accepted that.
That has tripped up a lot of people. The diagram clearly says facing the connector on the PCB. That socket will be the mirror image of whatever plug is on the end of the cable.
Post by: m3741 on Fri, 08 February 2019, 12:52:39
YAY!
Turns out the problem I was having before was because of a faulty ps/2 to usb adapter.
(http://i2.photobucket.com/albums/y13/m3741/Seleccedilatildeo_098.png)
So, for future reference, if anyone ever comes to this post looking for answers here is the pinout order as seen on the above pic, from left to right:
Pin1, yellow wire: Data
Pin2, white wire: Ground (sometimes called V-)
Pin3, red wire: Clock
Pin4, black wire: V+
Although Fohat.digs' diagram was for a different IBM keyboard, the wiring colors were spot on.
The PS/2 adapter I'm using that works shows up on Linux as:
"Holtek Semiconductor, Inc. PS/2 keyboard + mouse controller"
It looks like this in lsusb:
Code: [Select]
T430:~ # lsusb -vs 001:003
Bus 001 Device 003: ID 04d9:1400 Holtek Semiconductor, Inc. PS/2 keyboard + mouse controller
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x04d9 Holtek Semiconductor, Inc.
idProduct 0x1400 PS/2 keyboard + mouse controller
bcdDevice 1.43
iManufacturer 0
iProduct 0
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 59
bNumInterfaces 2
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 1 Boot Interface Subclass
bInterfaceProtocol 1 Keyboard
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.10
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 65
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 10
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 1
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 1 Boot Interface Subclass
bInterfaceProtocol 2 Mouse
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.10
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 157
Report Descriptors:
** UNAVAILABLE **
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 10
can't get debug descriptor: Resource temporarily unavailable
Device Status: 0x0000
(Bus Powered)
T430:~ #It looks like this in real life:
(https://images-na.ssl-images-amazon.com/images/I/31%2BdP6ugeTL.jpg)
Its sold under too many names and brands.
I'd like to thank you all for your help!
Post by: invariance on Fri, 08 February 2019, 17:58:39
My Model M is behaving weirdly and needs fault finding too
Sent from my iPhone using Tapatalk