Hi all!
Recently I picked up a VIC-20 - it came without a power supply, and the guy who had it never saw it running...but oh well - that's half the fun!!
I've got it powered on with a 11v DC power supply (I have a new 10v AC trans coming...) and it does power on - the power light comes on, anyway. Nothing on video.
Checked the 5v line...perfectly smooth at 5.02v
Checked the vcc pins on the 6502 and 6560, both are fine
Checked for a clock signal...bingo! There isn't one! Just a 2v low signal, steady.
Tried bending away the clock-out pins on the 6560...no change - clock line still at 2v, pins 35/36 at 0v
Checked the clock-in, showing a good frequency albeit low voltage - only about 2.2v peak
Pic is the signal on pin 39 of the 6560, taken at 2v/div and 0.2uS/div
https://preview.redd.it/h2pdx11rwu171.jpg?width=1000&format=pjpg&auto=webp&s=d05543da9b269bebf4aa137c994c5acbb1478bef
Doesn't this signal have to be 5v peak? How could I get it to that level?
I have read a few discussions about replacing the 7402 in the clock generator, but I don't have any. Besides, the 7402 in my vic-20 seems to be functioning correctly.
Any ideas would be great!!!
Edit:
https://preview.redd.it/4schnmn2lv171.jpg?width=1000&format=pjpg&auto=webp&s=6882300f97ff21acdf3d83bb2df33db6e90621e7
So I have acquired two VIC-20s that belonged to my mom's family, both with the two-prong power supply. However, one has the normal black badge with "Commodore === VIC-20" printed on it, and the other has a black and gold badge with no rainbow. I opened them up and they both have two odd black metal plates over the cartridge slot and something that looks like a battery under one of the plates that swivels about 20° which isn't in other VIC-20s I have seen. other than that there isnt that much different. I was wondering a couple of things. 1) Which one is older? I have a sneaking suspicion that the gold badged computer is the older one, but I might be wrong. 2) What are the black plates? I'm assuming that all older VICs have them because between the two computers they are identical on the inside. It might be a mod that was sold in a kit that was installed in both computers for some reason. I have no idea what the "battery" underneath the plates even is though. I probably sound really dumb right now but this is the first computer I have ever opened up and reassembled. I hope someone knows what i am talking about, thanks.
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I have an older VIC-20 and it uses the 9V power supply (Part No. 902502-02) instead of the round connector on later models and the 64. I was wondering if there was a newer power supply being made like the nu-brick for the 64 or if there is a way to keep it from frying my VIC like people say they do from time to time. I have a power supply that works, and I have plugged it into my VIC and it works. I am just wondering how I can supply power to my computer without ruining it. Thanks.
In really nice condition. Not yellowed, still had all the original documentation, even the warranty envelope.
Was driving past a local garage sale and spotted the box on a table. Pulled over right away and practically sprinted over. Got it home, tested the PSU, all voltages are within spec, and it fired up right away.
Didn't have the tape drive or any cartridges with it, unfortunately.
https://imgur.com/a/UEi4yYt
