Vic 20 worked for seconds then distorted screen

asapreta · Post by **asapreta** » Tue Jun 30, 2020 2:09 pm

Hi guys.

I just received my first Vic 20 and when I powered it on I was able to see the "boot" screen, with about 4kb free and typed some keys to test the keyboard then the screen distorted like the picture below:

I am using the built PSU I use for my c64's with no problems on them.

As it is my first Vic20 I don't know where to start to look for the problem.

Thanks for any advice.

groepaz · Post by **groepaz** » Tue Jun 30, 2020 2:25 pm

I'd suspect a problem with the clock generator if this was a C64. Probably similar with a VIC

asapreta · Post by **asapreta** » Wed Jul 01, 2020 7:55 am

groepaz wrote: ↑Tue Jun 30, 2020 2:25 pm I'd suspect a problem with the clock generator if this was a C64. Probably similar with a VIC

You may be right.

I will see if I find a M53202P or similar here.
I'd suspect the TTL 7402 isn't the same, right?

asapreta · Post by **asapreta** » Thu Jul 02, 2020 6:40 am

Tested the 7402 and the Crystal and both are fine.

srowe · Post by **srowe** » Thu Jul 02, 2020 6:42 am

Most likely to be the VIC chip, you probably don't have a spare to swap it out?

asapreta · Post by **asapreta** » Thu Jul 02, 2020 6:46 am

srowe wrote: ↑Thu Jul 02, 2020 6:42 am Most likely to be the VIC chip, you probably don't have a spare to swap it out?

I was wondering about it too. But no, I don't have one. It is my first VIC-20 and it just worked for seconds.

Denial

Vic 20 worked for seconds then distorted screen

Vic 20 worked for seconds then distorted screen

Re: Vic 20 worked for seconds then distorted screen

Re: Vic 20 worked for seconds then distorted screen

Re: Vic 20 worked for seconds then distorted screen

Re: Vic 20 worked for seconds then distorted screen

Re: Vic 20 worked for seconds then distorted screen