Good Buy ($1 power supplies)?

[MaxPower]

They were for Amstrad computers apparently. Their output specs are 13V, 1.9 amps. Most have no labels; the ones that do say Oct 1987 but they look new (some boxed, all in plastic bags with the cords tied with twisty-ties). They had a bunch of them (I'd guess at least 40).

I only bought 4 of them. I was tempted to buy 20 of them but I wanted to test them first. May have to make another trip to town tomorrow....

[mth5044]

Crap shoot, really. AC or DC?

[induction]

Great score!

Unless they're damaged or something, those can be easily converted to audio-quality adapters that will be nice and quiet with pedals. 13VDC, 1.9 amps will feed a whole pedalboard. Build a small box with one or more 9V regulators and some decent filtering. Daisy chain as necessary. If they're AC, add a rectifier to the front end of the regulator circuit.

[tubegeek]

1987 - the electrolytic caps are likely bad by now, that's almost 30 years. Sorry to be Debby Downer... 

[MaxPower]

@Tubegeek: Yeah, I thought about that but the transformers, rectifiers, etc. should be okay shouldn't they? Assuming they weren't sitting in a pool of water or something. I figured as long as the transformers were fine it was worth it. The housing has 4 screws, so hopefully its not also glued or something and easy to take apart if necessary.

They all registered 15.8V-16V on my DMM under no load condition so, hopefully, that's a good sign.

@mth5044 and induction: The output is DC.  Yeah, I was thinking one for the pedals, maybe a couple for a small stereo hi-fi amp.

[tubegeek]

@Tubegeek: Yeah, I thought about that but the transformers, rectifiers, etc. should be okay shouldn't they?

Should be. But if the caps fail they may take everything else out with them. It's just a high-likelihood failure since they are so old. But no harm in giving them a spin (especially at that price.) And they won't take out your pedals if they fail, so, give it a shot!

I figured as long as the transformers were fine it was worth it. The housing has 4 screws, so hopefully its not also glued or something and easy to take apart if necessary.

If you can get 'em open easily, I'd say go ahead and swap the caps as preventive maintenance. But really, I'm just being Nervous Nellie.

They all registered 15.8V-16V on my DMM under no load condition so, hopefully, that's a good sign.

See if the DC is smooth under load - that'll be the real test.

[amptramp]

If they have been in use before this sale, I might agree that the electrolytic capacitors have aged a bit, but if these are new supplies that have never been used, the failure rate should be much lower.  It is fairly normal to do a comprehensive capacitor replacement on antique radios but even then you find some electrolytics that are still good and this is in 60-year old equipment.

[MaxPower]

Thanks for the advice. I'll replace the caps. On that note: Turns out the housing is not so easy to open. I'll open one up one way or the other.

Edit:
I opened one up. It has a fuse. Also, the caps are 3300 uf. Is that good enough as far as minimizing ac ripple?