Have a VIC20 that I finally got a 9V AC 3 A power adapter for and fired it up to see the condition it is in and it seems to function on a very basic level, but the video display is jittery. I have one cartridge, when installed, looks very courrupted, but booting without the cartridge into basic is very readable. Only other cart I have is a 16K expander, and interestingly when I insert this one, the screen clears up by a large margin and there is no flicker, however you get a noticeable line scrolling down through the screen about every 2 seconds.
Without knowing a whole lot about commodores, the troubleshooting guide from Ray Carlesen leads me to believe maybe UC2 (74LS04)would be a good place to start? I checked the 5 volts at the 6502 and I get 5.1Vdc, however unless I am checking wrong I can't detect 9Vac on the user port and the datasette does not work (no motor action) when the LOAD command is issued. I swapped 6502's without a change, and I have tested the VIA chips and they are good. I don't really have any other parts in my stash to try without placing an order, maybe a 74LS04?
Thanks for any suggestions to help this computer along.
ps. Sorry I couldn't figure out how to post all links in the same post without it saying I was going to loose my original post.
Without knowing a whole lot about commodores, the troubleshooting guide from Ray Carlesen leads me to believe maybe UC2 (74LS04)would be a good place to start? I checked the 5 volts at the 6502 and I get 5.1Vdc, however unless I am checking wrong I can't detect 9Vac on the user port and the datasette does not work (no motor action) when the LOAD command is issued. I swapped 6502's without a change, and I have tested the VIA chips and they are good. I don't really have any other parts in my stash to try without placing an order, maybe a 74LS04?
Thanks for any suggestions to help this computer along.
ps. Sorry I couldn't figure out how to post all links in the same post without it saying I was going to loose my original post.
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