Power up procedure for long sleeping amp?

[Kma4444]

Hey all, I have searched around and can't seem to find a suggestion for how to power up amps that have been sitting for who knows how long. I inherited a number of PL amps from my dad and don't want to just toss power to them and pray. Can someone suggest a smart way to wake these up to find out what sort of condition they are in. I did slowly power a 700 up with a variac and it didn't do anything odd. Then plugged in my phone and it played some sound. But when I went to a little more volume it popped the main fuse. Fuse was black inside. So I have stopped there. Don't want to cause problems unnecessarily.

Thanks

 

[laatsch55]

A variac and dim bulb in series works well..

 

[Kma4444]

I gotcha, so power it up that way, if it seems alright then hook up speakers and give it a try?

 

[laatsch55]

Check for DC on the speaker outposts first .

 

[laatsch55]

That 700 popped the mains in fuse or a rail fuse?

 

[Kma4444]

Mains in, it shut off the amp when it blew. Pardon the newb questions but DC is measured speaker + to - and the max allowed is how much?

Thanks again

 

[laatsch55]

Correct, no more than 1/2 volt DC

 

[Kma4444]

Copy that, thank you

 

[mlucitt]

How about telling us how many and what kind of PL amps you inherited? Some of us enjoy the drooling...

 

[Kma4444]

If I remember my inventory, lol, it was 2 700s, 2 700Bs, and 4 400s which if I remember right 3 are 4 fin. There is still more things at my dad's place I need to collect, but I think that was all the PL stuff. I know he had a couple PL preamps but I haven't run across them yet. He had a lot of stuff, as an example, 11 Yamaha DSP-3090s. I have no idea why he had that many and those were just the ones he had that weren't in use. He had given me two a few years ago and there was one in use at his place. Not sure what the fascination was with that particular unit, I mean they work well and sound pretty good, though I don't know why one would need that many.

 

[wattsabundant]

When you "walk up" an amp using a variac and a 100 watt incandescent light bulb, do not connecect anything to the inputs and most importantly the outputs. There will be a considerable DC offset until all of the circuits are fully operational. The point that everything stabilizes will ocur any place from about 30 volts AC until 80 volts AC. During this time the meters may peg. Bringing it up slow with a variac (about a minute) reforms the capacitors if the amp has been sitting for a few years. The light bulb, limits the current into the caps.

 

[Kma4444]

That's great information. I really appreciate it.