Rectifier tube trouble

[jay66]

I pulled my amp out of its cabinet when I firs got it and found this broken round piece of plastic floating around in there (F***ing UPS). I didn't think much about it at the time and tossed it but today I was changing the peamp tubes and looking things over and see it was the round plastic piece off the bottom of the rectifier tube (EH 5U4). It still works fine but I have read that you can put a rectifier tube in wrong and damage the amp. My question is, when I change it how will I know I have it in there correctly? Anyone Know where I can find some Photos of how they should go in? <By the way Mike the Tung Sols sound great Thanks again>

Jay

[AdmiralB]

You mean the guide pin? Every broken pin I've seen has left some material - or a little 'gouge' - in the base, enough to tell where the index key used to be. You can use that, and look at the socket to determine how to install it...or you can buy guide pin 'replacements' - little wafers that glue on the tube base and have a new pin attached.

You're more likely to kill the tube than the amp, if you install it wrong.

[jay66]

The whole round bottom piece of the tube is busted off and like an idiot I threw it away not knowing what it was. I thought it was something that got left in there when they built the amp. Its when I put a new tube in how do I tell if its in right?

[brad347]

putting a new tube in there will be a 'key guide' in the plastic base.

It is impossible to put a new tube in wrong as long as the amp's tube socket is intact.

[jay66]

The socket its self looks fine, as long as I can't put a new one wrong I should be OK. For now I'll just leave it alone because it still works fine.
Thanks

Jay

[Blue Strat]

The socket its self looks fine, as long as I can't put a new one wrong I should be OK. For now I'll just leave it alone because it still works fine.
Thanks

Jay

If it's in and working, take some White Out (or paint or nail polish or whatever) and mark the base with a vertical line as close to the back as possible. That should help you install it correctly next time.

The good news is that it's a 5U4. You can get a NOS 5U4 for $20 that will likely out last us (or at least me;) )

[AdmiralB]

You mean the outer part of the base broke off (but the tube is still in and working)?

If the tube isn't in danger of falling out, I'd say leave it and play on.

[jay66]

You mean the outer part of the base broke off (but the tube is still in and working)?

If the tube isn't in danger of falling out, I'd say leave it and play on.
No just the center piece with the guide pin is gone. It has a clip on the outside that holds it in place. I'll leave it alone for now and pick up a spare later on. It worried me because I read somewhere that you could put a new rectifier tube in wrong and didn't have the complete old tube to go by. As long as it can only go in 1 way I'm good to go.The white out trick is a great Idea thanks.

[John Phillips]

Without the center guide pin, there are 8 possible orientations - one will work, four will do nothing at all, and three will damage either the tube, or the amp if you're unlucky (and will certainly blow the fuse). If it's working now, you've got it right. Mark the tube and don't worry about it - as long as you don't take it out the guide pin serves no purpose.