I built the optimized circuit, i have checked and rechecked it for short circuits, over and over, with my multimeter on low resistance check… there are no shorts, my circuit is the same as that in the schematic..
now, i have 2 psus that both make 5VDC perfectly, but the 9VAC is no longer functioning.. i get no power out of the first and last pins…
any idea what might have caused that? it’s frustrating to lose a powre sypply, but two is really a pissoff.
it’s a good thing i have about 15 c64 PSUs…
i deslodered and then resoldered it in another part of my strip board… lo and behold, i get a steady 9VDC out of the regulator, and a steady 5VDC out of the other part of the circuit..
now to power up the core board..
Turns out i had a blown bridge rectifier… it was taking the 9vac and then blowing up my PSUs.. i lost 3 PSUs troubleshooting this damn thing…
I am also using optimised PSU for my 8580 SID and I noticed the regulator heats too much when no SID is powered on. I suspect I blown a fuse on C64 PSU probably because of that, but cannot exclude It was my fault. Can I build some better optimisation? It seams this one is not so perfect.
? yes regulator will be warm (thats normal), but i don’t think that this would be a reason, that your C64 PSU will blow away ;D
The regulator will shut down if it gets close to exceeding its thermal limit, so you’d need to work very hard to kill one of those babies. More likely that there was a short somewhere, allowing the PSU’s to run unloaded and killing the transformer.
Sure, regulator is heating, but to me it seams not normal if regulator is much more hot when no load than when SID is running.
mhhh… Where should energy goes to? It’s normal that 14V ->9V will warmup your regulator… and this part works only with higher incoming Voltage!
if you are to scared, you should use a heat sink…, but i work 2 years constantly with my device and i’ve got never a problem…
I already mounted some heatsink to feel better…
The regulator will shut down if it gets close to exceeding its thermal limit, so you’d need to work very hard to kill one of those babies. More likely that there was a short somewhere, allowing the PSU’s to run unloaded and killing the transformer.
It was the bridge rectifier that was shot on mine.. i replaced it and the circuit works..
but now i only have one fully tested and reliable PSU.. my other ones will need to go through a load test now to amke sure there’s no ripple in the 5VDC…