Re: Electrolytic Caps in CBM equipment

From: silverdr_at_wfmh.org.pl
Date: Mon, 26 Nov 2012 19:39:33 +0100
Message-Id: <C0ECFA04-A20D-4C8D-AC57-67B50B55429B@wfmh.org.pl>
On 2012-11-26, at 19:23, Gerrit Heitsch wrote:

>> Got this one fixed. Crashing was unrelated to the lack of colour. Crashing was caused by broken KERNAL socket - replaced and crashes disappeared. Lack of colour was a bit more tricky though. I was hunting it for some time until I started watching the chroma waveforms on different boards recently, including the one in question. I noticed that on other boards trimming the crystal frequency leads to loss of colour and setting it back brings the colour back. But on this board no.. So I replaced the trimmer and adjusted it so that I get colour every time now. It sorts of explains also why the colour was more likely to appear after some time and less likely when cold - frequency drifting due to temperatrue difference.
> 
> Hm, never had one of those go bad... But then, it's hardware, it will fail sooner or later for someone.

Yeah... me neither (and I repaired hundreds if not thousands of those machines in the eighties and early nineties) - the reason why I didn't even think a bit of this. But it was the case here. Maybe some poor storage conditions (it was quite dirty from humidity derived deposits all over the board when I got it) ? Who knows.

-- 
SD!


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Received on 2012-11-26 19:01:37

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