I got a new VIC-20 today. Turns out that it's a CR model with the VIC chip soldered to the board, which means I can't easily pop the VIC chip out and stick it in my old two-prong VIC-20 with an ailing chip
Anyway, both my original VIC's datasette, and the new one don't work on this CR VIC. It appears that they don't get any power. The VIC detects when the play button is pressed, but the motor doesn't start. Both these datasettes work in my old VIC.
I've checked the fuse, which seems to be fine. I've also checked the voltage over pins 1 and 2 of the cassette port when the datasette is plugged in - it's giving me about 4.8V. I'm not sure what else to check - it would be great if someone can give me some pointers.
Ah! It seems to be a loose connection in the power socket. Not sure how that tallys up with my 5V multimeter reading on the cassette power line. I was swapping joysticks between my VICs (just to double check the 6522) and noticed that the datasette power came on! I quickly loaded up Matrix and it all worked.
Annoyingly I can't reproduce my good luck. If I turn off the VIC, jiggle the power plug, and turn it back on, it either supplies power to the datasette or the VIC. Not both at the same time! At least I know that it all (more or less) works. I just need to examine the power socket and maybe replace it.
Yeah, I know. I'm just talking to myself. But I thought I'd finish the tale!
I took the motherboard out of the case, and sure enough the power socket connections were dodgy. Either the solder had been filed down after manufacture, or years of rubbing against the case had rubbed down the solder. Anyway, the solder was worn down so far as to expose the PCB connectors on the socket, and the result was an intermittent connection. After resoldering the socket to the motherboard everything is working great. And to top it off my new datasette even managed to load JetPac, which had always failed with the previous one.
Happy to have a fully functioning, full colour VIC!
orion70 wrote:Congratulations on your success!
You were lucky that the intermittent connection didn't burn anything inside the VIC .
I know! When touched the power lead with the joystick plug and I heard the cassette motor turn on I thought - yikes!
The chap I bought it from said that the "power switch" had been dodgy for years. I can't believe nothing had got fried in all that time. On a related note, the power supply makes the scariest buzzing noise. I think I'll stick to my C64 PSU for now.
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