Re: PLA replacement

From: Gerrit Heitsch <>
Date: Sun, 02 Dec 2012 14:20:53 +0100
Message-ID: <>
On 12/02/2012 02:08 PM, wrote:
> On 2012-12-02, at 13:56, Gerrit Heitsch wrote:
>> I replied directly since I didn't want to post a 500K picture to the list.
> As far as I know Uz, I'd expect the list not to let you anyway ;-)
>> If someone else would like a picture of the KU board, send me an email.
> If you agree I can put it online and post a link here.

The board isn't mine, I only had it for repairs. I also have a hires 
JPEG (5MB) of it in case someone would like it.

There is also a detail about the KU board that everyone who owns one 
should address as quickly as possible:

Next to the 74LS629 (inside the VIC 'can') are 2 capacitors, C107 and 
C108 (10”F/25V). The original capacitors on the board I photographed 
were small and black. And they leaked... the stuff from C107 had eaten 
through a trace and resulted in pin 15 of the 74LS629 no longer getting 
about +4V. Result: No 17.734 MHz clock signal since the oscillator 
didn't start. They don't leak much since they are so small, the damage 
was not visible until I removed the caps from the board. Since then 
other people on the forum64 have reported the same leaking problem on 
their KU boards.

So if you have a KU board, replace C107 and C108 (also clean away any 
leakage). They are also present on the 250407, but are a different kind, 
haven't seen any leaks there yet. Good idea to check anyway.


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Received on 2012-12-02 14:00:41

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