H3nrik V! wrote on 2021-03-02, 05:24:
brostenen wrote on 2021-03-01, 20:24:
H3nrik V! wrote on 2021-03-01, 09:11:
Didn't actually buy this per se - as the cost was "If you ever get it to work, invite me to a gaming night". A friend texted me yesterday as he was cleaning out his garage and asked if this was something for me.
Apparently it worked 10 years ago, when it was last powered up. I don't have anything to connect it to (or maybe the old TV has an analogue tuner) and I'm also reluctant as I've heard the Powersupply should pose a great risk of frying the computer - or is it just a matter of opening and recapping?
First you need to check voltages on that PSU. Just keep in mind that it can blow at ANY time. Most of the times it releases a massive spike in voltage, in few situations it just dies. Anyway. If no picture, and voltages are fine, then it can be anything from dead VIC-II, over dead PLA to dead memory chips.
Getting it to work is most of the fun right? 😁
Yeah, the fun is the process 😉 well, as I'm an electronics engineer, and the C64 being relatively simple, some debugging should be doable.
But then again - will a recap of the power supply help anything, or is it just a transformer? And where would be the right place to find and ask for information? Is there a subforum here on vogons, that suits?
That is a nice job you have. Were you educated down in Sønderborg? I have a number of half finished educations from back in the 1990's, and I were a student down there at "skolepraktik". Back then it was called "Datamekaniker". Today it is just "Datafagtekniker". However, we were screwed over by the boss at skolepraktik, as he did not give us any jos that were related to the education. He sure was inventfull and had us all clean old 8088/8086 bank computers, that he then could sell for a profit. We were told by him, that all education related practice and chores, were something that we had to do strictly in our spare time. Well... It does not take much brainpower to figure out, that nobody passed any tests and examinations in class.
The PSU you have, are one of those wedge ones. It is a standard old school linear AC and DC power supply. Yup. 9v AC and 5v DC as far as I remember. The voltage regulator is the bad news regarding all Commodore64 PSU's. It is only rated at exactly what the machine is supposed to be supplied with. And taken that it is from 1984'ish, then it has degraded and will short out at some point. The good news about your PSU, is that most of the DC part is not enclosed in Epoxy. The square white ones have all parts inside a big lump of epoxy.
As you can see, then it is a relatively simple device. Nothing strange or anything, other than a regulator that are not rated high enough. When it goes, then it goes. And then it will send a major surge of power straight into the 5v DC line. The chips inside the machine do not have any protection. You know. Commodore cheap'ed out on so many things, and engineers like Bill Herd have said so many times, that they designed all machines for a max of 3 or 5 years use. He never ever thought or believed that we would still play with 8bit machines in 2021.
I will be sending you a PM, regarding places that you can ask for help at. Vogons do not have any sub forum for these old 8bit platforms, or even 16bit such as Amiga or AtariST.
Don't eat stuff off a 15 year old never cleaned cpu cooler.
Those cakes make you sick....
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