Denial

If you already have a couple of these PSU's and they work fine with the C64 and 128 then I don't think there is too much reason to be concerned. I could be wrong, but I think the C64 has 3 large electrolytic capacitors for filtering the voltage rails versus the VIC-20's one cap which may explain why...

I finally got around to catching up with my uncle who is a technician. I'm not hugely experienced in electronics. As you guys know, the PSU's from Electroware.pl on Ebay consist of a standard transformer for the 9v AC and a Meanwell switch mode for the 5v DC. The Meanwell 5V switch mode was where al...

Yeah unsure about that.

Anyway, I have a relative who has infinitely superior electronics knowledge to me. I'll get him to check the PSU with an oscilloscope and see if there is a way we can filter it, if possible.

Can you tell me what monitor you are using? CRT or LCD? Does it have an old-timey RF input? Antenna? What kind of power connection does it use? Two or three prong? And is everything connected to the same AC mains? Like on the same power bar or somehow maybe the monitor is plugged with a 30 foot ext...

Here are some pics I took of the power supply.
This is a 240v PSU for the Australian region. It has the round 7-pin DIN connector for the VIC-20.

Maybe the switching frequency inside the switched mode power supply is similar to one of the video frequencies (frame rate, line rate, dot clock, colour subcarrier)? Would there be any way to adjust this? I opened up the PSU and the 5v switch-mode looks pretty non-serviceable. If it is the power su...

So it seems then that it could be the new power supply causing the video noise. I opened mine up and it has a Meanwell 9v transformer and a 5v switch-mode PSU. I wonder if it's the switch-mode causing the noise? Other than that there doesn't seem to be much more to them. If it is the power supply ca...

Another possibility is that the filter cap (C39 in this schematic: http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/vic20/251027r2.gif) is dry and needs replacement Thanks groepaz. Yeah that was my thought too, so I replaced that as well as all the rest of the electrolytics but, unfortun...

Hi guys, Thanks very much for your replies. @mathop: I believe this board takes 9vAC (according to the serial label underneath) and also 5vDC. It is a smaller late revision board that takes the 7 pin DIN power connector. The PSU I am using is a new one from the following link: https://www.ebay.com/i...

Hi all, I have an issue with video noise on my PAL VIC-20. It manifests itself as 2 horizontal bars of noise that slowly scroll down the screen. I have replaced both the electrolytic and tantalum capacitors in the video circuit hoping that perhaps they were contributing to the problem. Unfortunately...

Hi everyone, Just wanted to say a quick hello. Long time fan of the VIC-20 as it was my first computer. I was one of the odd ones that never got into the Commodore 64, so it never had the same nostalgia or appeal for me as did the VIC-20. Completely skipped past the C64 and went to Amiga. :D Hoping ...