Basic keyboard repair -- hints welcome

[niftyprose]

Hi chaps, my first tech request. I bought an interesting keyboard off ebay.de last week. (Lasciate ogni speranza...)

http://www.ebay.co.uk/itm/230946227022? ... 1439.l2649

It's from a luggable Philips logic analyzer, late 80s, alumin(i)um-cased and with Omron switches -- there was some discussion either here or on Geekhack, but I can't find the thread. The keyboard has standard layout, no unfamiliar keys, and a DIN connector -- given the vintage, it's unlikely to be anything other than AT-comtpabile. I installed it via a DIN--PS/2 converter today. Nothing (much) doing.

Initially I got all three LEDs lit up. They didn't respond to the corresponding lock keys.

I then rebooted and the LEDs started responding to the lock keys normally.

However, there is no character output.

The fact that there's power to the LEDs suggests to me that I'm dealing with something other than a short to the cable. Given the very specific symptoms, can anyone make any suggestions as to where to start looking?

Best, W.

[urbancamo]

You could start by cleaning and re-seating all internal connectors. Check the cables carefully for signs of damage. After that I'd check chips in sockets are seated correctly. Then it's a case of checking for dry solder joints.

[Kurk]

This thread?
http://deskthority.net/photos-videos-f8 ... it=philips

[Findecanor]

The layout on that keyboard is quite close to the IBM Model F XT which talks the XT protocol. XT and the AT protocol have the same exact type of DIN connector, so I wonder if it would talk XT.

[niftyprose]

Thanks everyone, but especially Findecanor -- I should have thought of that one myself. I'm aware of the difficulty (or perhaps impossibility, given mhy limited time) of getting an XT board to hook up to a modern computer. Does anyone know an easy way of checking whether it's AT or XT? Best, W.