exxos's Atari, Amiga & retro forum

stephen_usher wrote: 30 Nov 2023 11:51 Oh dear. The fun of maintaining old hardware. :-/

I know, and it was running brilliantly the other day :(

There are no shorts on the power lines, which is something I suppose.

Also not a dead backup battery...

@rubber_jonnie so does the psu seemto work? Trying to think if I still have the old psu.

PhilC wrote: 30 Nov 2023 13:00 @rubber_jonnie so does the psu seemto work? Trying to think if I still have the old psu.

Well I get the right voltages that's for sure, but I can power it from my bench PSU (5v only at this stage):


I get power on:


But it won't recognise my Fenrir, which is a bit disturbing.

@rubber_jonnie oh that’ll suck, that will be a pain if the fenrir has died already

PhilC wrote: 30 Nov 2023 13:53 @rubber_jonnie oh that’ll suck, that will be a pain if the fenrir has died already

As it goes, it hasn't...


Looks like maybe it is the PSU...

Definitely PSU, it's just not delivering enough power. According to the silkscreen it should be 5.2v at the pins, but I'm getting 5v, so I'm guessing there aren't enough watts to run.

Wondering if one of the caps in the PSU (I recapped it recently) has gone bad.

So it's +5V and +12V from the supply?

Usually +12V is derived from the +5V. What's that like?

I'm guessing that without the CD drive it doesn't actually need the +12V anyway, so you can probably run it all from a wall wart.

stephen_usher wrote: 30 Nov 2023 14:54 So it's +5V and +12V from the supply?

Usually +12V is derived from the +5V. What's that like?

I'm guessing that without the CD drive it doesn't actually need the +12V anyway, so you can probably run it all from a wall wart.

The 12v from the PSU is about 11.9v, but if I'm reading it right it only really needs it for the SCART.

Powers up with just 5v, if I hook up 12v it makes no difference, and in fact the 12v shows no current draw at all.

@rubber_jonnie well good luck hunting down the cap, I’ll still look for that PSU just in case.