2-Prong VIC-20 Suddenly won't power up

[jsonova99]

This is my first post (other than the intro) and I am very new to the VIC-20. I have a 2-prong unit with a 1981 board build date. Power brick measures 10.65VAC. Everything was working fine, I was playing some games with the kids, about 45 minutes of use. I powered down to swap cartridges and when I went to power back on, nothing. No light and not even a flicker on the screen. Fuse is not blown and verified the switch is good with a multimeter because it's a little finicky on this one so I wanted to make sure it hadn't broken internally. When the event occurred, I could feel that it was warm inside from the cartridge port. I'm sure this is a thermal issue. I'm leaning towards the internal power supply being the issue, especially since the LED is suddenly dead. But I'm just curious if anybody else has run into this issue. I'm in the midst of a move, so a lot of my electronics gear is packed so it may be a little while before i can really dig into this, but I wanted to get a description up while it was fresh.

Thanks,
Joe

[jsonova99]

I was just doing a little research on Ray Carlsen's site and he points to the bridge rectifier or voltage regulator in these cases. These make sense, I may look at re-caping as well if I'm in removing stuff anyway. I'm hoping because the fuse didn't blow that maybe I haven't caused any damage to any chips. My board is about 1/4 socketed.

[mrr19121970]

remove and clean the fuse. check it with a continuity meter. squeeze the fuse holders together with pliers and re insert fuse. after this you are going to have follow the traces measuring from power inlet, fuse, bridge rectifier, smoothing capacitor, voltage rectifier, fuse, & led.

[mrr19121970]

I think it was Kakemons who also mentioned that the bridge rectifier can get so hot that it can desolder itself.

[eslapion]

I think it was Kakemons who also mentioned that the bridge rectifier can get so hot that it can desolder itself.

If that happens then it means one of the diodes in the bridge has failed and is conductive both ways.

The same often happens on old VIC-1540/VIC-1541 with long board.

[Bobbi]

VIC-20 suddenly won't power up -> owner suddenly feels a sense of loss.

I hope you are able to nurse your baby back to health!