Re: 6561-101

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Wed, 26 Oct 2016 10:39:03 +0200 Message-ID: <5e3370e2-e9c0-7cdf-5218-e4758a279d0b@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 10/26/2016 03:00 AM, Clockmeister wrote:
>
> Whilst mask ROM (and RAM for that matter) failures are common on vintage
> equipment, the last two VIC-20's with a black screen that I repaired had
> a bad 6561-101.
> In my case both were easy to diagnose by simply plugging in a cartridge
> or blind loading a game. On both occasions the game you could hear the
> game playing even though there was a black screen.

While we're at it... Does someone know the difference between the 6561E 
and the 6561-101?

Another common failure in a VIC-20 are the MOS 65245 if they are present 
on the board in question. They can be replaced with 74LS245.

  Gerrit

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