Marshall SV20H MKII Need replacement relay

[CoopDaKill]

Hello! I’m looking for replacement relays for a Marshall SV20 H MKII. It’s marked P-5. 2A/30vdc - 0.5A 125vac. And 190 at bottom.

This amp head powers up and sounds fine for 5-10 minutes, then starts popping, then no audio output. I’ve done all the usual deoxit, reflow solder joints, retentionef tube sockets, tested tubes. Finally I used a chopstick to poke around while amp is in play mode. When I poke the relay, the signal comes back. So, I figure it’s a bad relay. Any other thoughts on this?
Thanks in advance for your help
Coop

[Jon Snell]

I think they are 5volt relays; https://uk.rs-online.com/web/p/high-...elays/8154859/
I don't know who you use as a component seller where you are but the idea may help.
https://uk.rs-online.com/web/c/relay...ncy-rf-relays/

[CoopDaKill]

Thanks Jon. I’m in USA. I’ve since figured out it’s a 5volt. I can’t find a 10 pin replacement. I’m pretty sure it’s a DPDT, form C

[g1]

Maybe like this MEISEI branded P-5? You might need to chase down the datasheet to verify.
https://www.ebay.com/itm/171385423602

[Enzo]

First, have you simply resoldered it? Relay could be bad, yes, but poking it when it has solder cracks would also cause symptoms.

ALso google MEISEI P-5 and find other sources too.

[g1]

Another consideration would be whether there are actually 10 pins in use or if a couple are redundant. Then you could look at standard 8 pin types.
Is there a schematic available?

[Jazz P Bass]

I don't know if it is just me or what but most of the solder joints on the top of that board look like ass.

[Jon Snell]

If it isn't a dry joint, (which is highly likely as these relays are very reliable), Mouser stock them; https://www.mouser.co.uk/Search/Refine?Keyword=TQ2-5V

[CoopDaKill]

Thanks guys, I’ll look at it again. I agree, the solder looks terrible! The owner says he bought it brand new. When I told him that someone had been in it before me, he said no way! But that’s how it looked when I opened it up. He must’ve got a refurbished model. I’ll update you all when I dig back into it!

[CoopDaKill]

Jon Snell Thanks for the mouser relay link. That’s a 1 Amp. I need a 2 Amp. Or will that work?

[CoopDaKill]

Good news! Got it figured out. Turns out, the problem was a faulty TL072cp op amp. Which is located near the suspect relay! I had remembered a similar problem with a different amp, a while back. So, I thought I’d give it a shot. And that was the problem!

It’s sounding great. No more pops, zaps, noises, and it has constant signal! Luckily, I had two new TL072cp’s on hand. Mouser is out of these until December. Anyway, Thank You all for your time and knowledge! You are beyond appreciated!
Coop

[serge974]

Hi everyone,
sorry to bother you but I try to find out what is going wrong with my SV20H.
because I leave in a country where there are not a lot of tube amp technician
SV20H works well when I play it, then 10 minutes later, a white noise appears (I can still hear my guitar at the same level)

Could it be the same issue : TL072cp op amp?
I have change the préamp tube and check the connexions.
thank you!!

https://drive.google.com/file/d/11Nu...ew?usp=sharing

[The Dude]

You should start a new thread for your amp. All failures are not the same. That said, since it's likely to be heat related, I'd try some freeze spray to see if you can narrow down the problem area.