Need help with my Model M

[Zambumon]

I've recently bought a UK ISO Model M 1391406 which was almost perfect (no rivets missing, all keycaps, no scratches…). However, while testing the board I found out a couple issues:

1. The Numlock LED doesn't work. I suppose that this can be fixed easily, any guidelines before trying to replace the LED?

2. Both left and right control keys don't work. Could this be related to the membrane? Is the Unicomp's membrane compatible with ISO keyboards?

Finally, since I have a laptop, the SDL-PS/2 cable is kind of useless for me and I don't want to buy one of those PS/2 to USB adapters so I was thinking about buying a phosphor glow Colossus PCB. What do you guys think about it?

The problem with ordering a new membrane is that Unicomp's shipping is way too expensive.

[E TwentyNine]

The right and left ctrl keys share a trace and are the only two keys on it.

You want to pop open the case and take a look at the connector with the 16 leads, and look at the trace on the far left.  If you're lucky you can reseat the connector and it'll be fine.  Almost as lucky is if the break is outside of the assembly and it can be repaired simply. Look closely. 

[Zambumon]

The right and left ctrl keys share a trace and are the only two keys on it.

You want to pop open the case and take a look at the connector with the 16 leads, and look at the trace on the far left.  If you're lucky you can reseat the connector and it'll be fine.  Almost as lucky is if the break is outside of the assembly and it can be repaired simply. Look closely. 

I've unplugged the connectors and compared the traces. Unfortunately all of them looked exactly the same so my suspicious is that the problem isn't there.

In addition, I've tested the LEDs. It seems like the LED itself is fine and could be an issue with the connector too.

[E TwentyNine]

I've unplugged the connectors and compared the traces. Unfortunately all of them looked exactly the same so my suspicious is that the problem isn't there.

There's a part where the membrane transitions to connector, where the thicker portion is.  It not uncommon for the break to occur there and it's difficult to spot.  You may want to test on either side of that spot for continuity.

[Zambumon]

There's a part where the membrane transitions to connector, where the thicker portion is.  It not uncommon for the break to occur there and it's difficult to spot.  You may want to test on either side of that spot for continuity.

I've found out that the problem with the LED was the cable with this DIY "tester":





I'll check the connectors again.

[mike52787]

ISO and ANSI membranes are the same iirc. I have never owned a iso model m though, but Ive had 3 ANSI M's and I bolt modded each one of them, so Im somewhat farmiliar with the membranes. The hammer placement for the enter key is the same on ANSI and ISO boards, and there are contacts on the membrane under the stabilizer piece on the left shift. So, I think your best bet would be buying a new set of membranes and bolt modding the board. It is definitely worth it to do, and adds value to the board, even if the board has all the original rivets intact.

[Zambumon]

LEDs (kind of) fixed.







Detail of the original LED cable, pay attention to the first trace starting from the left, that was the NumLock LED, which didn't work.

EDIT:

As a temporal fix, I've remapped Control to the Caps Lock key.