Re: 6561-101

Hi,

It has black screen of course. I know that the Kernal ROM or VIC used to be 
the guilty ones. I have burnt a 27c128 with Kernal but still have to build 
an adapter so I cannot 100% rule out Kernal issue. The guy who sold it said 
that the 6502 is also sick (he has tried the CPU in an 1541), though with 
oscilloscope I have seen e.g. proper phi2 signal coming out. I have bought 
some Rockwell 6502s to replace it. Anyway even if it turns out that VIC is 
good it is better to have a spare IC.
I should hook up my logic analyzer to it but so far I had no time (or I was 
just too lazy).

Thanks
Hege


-----Original Message----- 
From: Francesco Messineo
Sent: Tuesday, October 25, 2016 10:23 PM
To: cbm-hackers@musoftware.de
Subject: Re: 6561-101

Hi

On Tue, Oct 25, 2016 at 10:07 PM, Hegedűs István <hegedusis@t-online.hu> 
wrote:
> Hi,
>
> I have a broken VIC20 which seems to have a bad VIC. Does anyone know 
> where
> can I buy one for a fair price?

what's the symptom? The 6561 was reliable enough. I can't remember
changing any in the '80s (but VIC-20s were already almost estinct when
I started repairing commodore stuff, so don't flame please).
As far as I remember, the 6561 was only used for the VIC-20.
Some IC traders might have them in stock, but I'd say it's a question
of luck to get good chips instead of bad/fakes nowadays.
I can help in troubleshooting your VIC-20 (as surely many others here)
if you're unsure.

Best regards
Frank

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