bad 4000t power supply?

[guru-666]

I think my power supply has gone bad.  Simply can't get any action to happen.  Do I need to check with a volt meter or are there any other ways to test?
I hear regular at supplies work, but do they fit?  anybody find a good brand or have a good source?
I was running a full house, toaster/flyer, par, tbc, Picasso IV and mkII060 with 2 hard drives, so I'm sure that puts a strain on the PS.

[Matt_H]

The 4000T is probably the easiest Amiga for which to source a new PSU. Mine died a few months back; replaced it with a standard 300W Antec. Strangely, I had to file down some plastic on the new P8/P9 connectors, but otherwise it's working fine.

[guru-666]

where did you get it?

[Matt_H]

Micro Center, a few years ago - was keeping it around as a spare.

I know AT supplies are getting harder to find, but there's probably still a few online shops that have them.

[guru-666]

so the general size, form factor is not an issue?  are all AT PS the same size?

ALSO how did it work out with the power switch?

[Matt_H]

No problem with the physical fit. The power switch was a moderate effort as it required dismantling the whole LED assembly. I didn't need to cut or solder anything if that's what you're worried about.

[guru-666]

how did you connect the power switch? not sure how that part will work think I found a suitable PSU

[Matt_H]

You should just be able to unmount the old switch and put in the new one. It's a standard mounting.

[guru-666]

thanks, let you know once I get it working!

[guru-666]

Well, I still have not fixed this.  The problem is odd to me.  -when I disconnect p8/p9 connectors the power supply turns on
-once I connect the p8/p9 connectors to the MB the power supply does nothing (the fan does not come on)
-if plug in only one of the p8/p9 the power sully fan spins.
-if I plug in only hd ans such, they get power.
-I am not sure I am measuring the power the right way, but I think I get 5 volts.

HELP

I got another PS off ebay, but it was not working....
-I have removed the battery on the MB because it was not working.

[CLS2086]

hum, sounds like a short circuit, or a dead "leaking" cap

[rkauer]

 What do you have inside the A4000?

 My advice: strip the machine to the bare motherboard, test the PSU. Add the CPU board, test again. Add the Floppy drive, etc.

 A bad cap in the motherboard can make a short-circuit who simply prevents the PSU to start (they have a "crowbar sensor" to avoid destroying everything when a short is detected).

 Also a bad floppy or bad keyboard can make funny things to circuit.

 Simply test one thing after another. Boring, yes, but the only way to discover where the problem lies.

 

[guru-666]

I am finally taking a look at this issue again....
How do I find "A bad cap" on the mb?  I have striped the machine down to the bare bones.....

[guru-666]

FIXED IT!!!!!
Oh man it was not even a power supply issue!  I had the audio video module on the wrong way.... DOH!  

[Matt_H]

Glad to hear you're back up and running.