Triac electrical problems

[davidimurray]

Hello everyone, long time no see.

Having not been on the forum for a while I am returning as our poor Triac at work is feeling a bit under the weather at the moment.

Firstly, we have lost the use of the Y+, 4,5 and 6 keys on the kepyad. Our electronic guys have changed all the chips relevant to the keyboard section of the main board but the keys still don't work. Our current theory is that the membrane has started to fail. Does anyone happen to have any info about the membranes or even have a front panel spare?

Secondly while testing the unit we misconnected one of the connectors and damaged some components on the VDU driver board (the one that connects to the front CRT). We have replace all the damaged components we can find, but the VDU resistor badly burnt is R4 - Could someone identify its value or give the colour banding. It's easy to see on the VDU circuit board.

Thanks in advance for your help

Cheers

Dave

[Denford Admin]

Hi David,

I'd be happy to help try and locate any spare bits we may have around here, but I don't know what I'm looking for really - can you post some pics?

[Denford Admin]

David,

If this is the board, then R4 is... 39ohms I think
hth

[Denford Admin]

I've had a look through the old filing cabinets and couldn't find any information on VDU's.
We may never have had that level of detail anyway - we'd have just replaced broken monitors with new ones.
These posts may help you though:
viewtopic.php?f=47&t=243&hilit=vdu+repair
viewtopic.php?f=43&t=497&p=1415&hilit=m ... pair#p1415