Mega ST2 psu failure

[Erikswe]

I got myself a Mega St2 and it doesn't power up at all, nothing at all happens. I thought I would start with the PSU. It has a Mitsumi sr188 Psu. Will the PSU start without load?

[exxos]

I got myself a Mega St2 and it doesn't power up at all, nothing at all happens. I thought I would start with the PSU. It has a Mitsumi sr188 Psu. Will the PSU start without load?

No, you need to load them for them to work properly. Lots of info on my site about PSU's..

http://www.exxosforum.co.uk/atari/last/psu/index.htm

[Erikswe]

Thanks for the fast answer. Well I did read there and it says the PSU don't work good with out load...
I have taken it out of the ST. It looks very much alike the sr98

[Erikswe]

Ahhh sorry...my English must be rubbish!! I totally misunderstood your answer...sorry!!!

[atari030]

Does the PSU tick by any chance? I have a pair of Mega's with odd PSU faults, so I'm curious to know.

The 12v fan on mine won't kick over unless the PSU is disconnected.

[mikro]

Yes, ticking is normal. See also here: https://www.exxosforum.co.uk/forum/viewt ... ?f=9&t=937

[atari030]

Without hijacking too much, PSU plugged in - no 5v, no fan spin. PSU unplugged 5v OK and fan spins (no tick). This happens on two PSU's and two Mega's, one PSU is recapped and had the rectifier bridge replaced, one not. If I plug in an STFM PSU - no problem, Mega's work fine. Just plain weird.

[exxos]

I think someone else had the same problem, can't remember what thread is was though.. probably bad solder joint on the PSU somewhere.

[atari030]

I wouldn't have thought it would be a bad joint on two PSU's. When the garage warms up a bit I will get in and have a closer look. ATM it is pretty cold in there.