Date   : Fri, 19 Oct 2007 17:21:14 +0100
From   : julesrichardsonuk@... (Jules Richardson)
Subject: Atoms and video output

Pete Turnbull wrote:
> If the TV is fairly modern, it would be worth trying another TV, if 
> possible.  I've had those symptoms with modern TVs where old ones work 
> fine, not just with an Atom but with my ZX80 and ZX81s.  Easier than 
> changing the modulator, though you might still have to do that.

Well as it turns out I should have done a few more tests first - I think I was 
half asleep last night :) Of the eight electrolytics on the board, seven had 
gone high-ESR (three that were so high they didn't even register on the meter) 
- I'm actually amazed that the system ran at all like that. Replaced them and 
everything sprang happily into life.

I've had a few duff 2114s on the other boards, and one system with a duff MOS 
ROM, which seems an unusual part to die (it'd invariably power up saying "CORN 
DTOM" and the keyboard repeat would have gone haywire)

Main problem's proving to be the keyboards, though. The issue 5 machines with 
the separate keyswitches are OK, but the issue 4's I have with the 
'monolithic' keyboards don't seem to have aged well at all - given that 
they're much less enclosed, I suspect that the key contacts are all badly 
oxidised...

cheers

Jules