Denial

I just bought a newer generation VIC-20 from Ebay and I'm having trouble.

It's a 9 pin din connector power supply. Sometimes it will power up fine. Other times, especially if a plug in a game cartridge, the power LED is very faint and the computer will fail to initialize (no video just snow).

To get it to work, with the power switch ON, I have to unplug then plug-in the DIN connector a couple of times. Sometimes it takes 2-3 tries, other times 5-7 tries.

I have re-seated all the chips. The power supply housing is glued together and have not opened it.

I plan to take voltage readings on the connector to see if the power supply might be the problem. Is the problem I describe a common failure? Are threre any other things I need to check/examine?

The power supply connector on the motherboard may have come loose and have to be re-soldered. I have seen this happen.

My old VIC-20 sometimes turns off when I trip on the lead, I think I know why now .
I'm gonna have to whip out the soldering iron and do some repair job.

Response to question:
I would identify if the Computer is the problem or the brick (PSU), I would test the voltage level on the brick first to determine if that is your problem.
They are a very unreliable piece of hardware.