Pet 2001 Problem. (320008 MB)

[dabone]

I got myself a pet 2001-8 today, with a blown fuse, I replaced the fuse and powered up and got smoke!. After powering down (yanking the cord), I removed the board and found the voltage regulator nearest p8 is shorted. They seem to be riveted in place. What do I need to do to remove the bad one?


Thanks.
Later,
dabone

 

[Pet Rescue]

Hi dabone

You need to break out a cordless drill or a variable speed drill, set it to a low speed with a nice sharp drill bit now with a very steady hand to drill out the old one. Once you've done that desolder your old one, fit new one with some thermal paste and use a nut, bolt and washer to make it easier next time it goes!

 

[dabone]

Ok, replaced the diodes and I now have a screen.
Unfortunately it looks like this.

I've reseated all the roms and ram.

Any good guide to trouble shooting the pet?


Pattern is different if the cpu is removed, I replaced it with a known good cpu from a vic and the pattern displayed above is shown again.


Any way to read the roms with a modern eprom programmer? (I've got a gq-4x USB programmer from mcu mall.)


Thanks!

Later,
dabone

 

[dabone]

Ok, machine is now up and running. (The first 7805 was out, so no +5 to part of the board.)

Now I do have 1 bad ram chip. Bummer.


Later,
dabone