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I have an original Valve Jnr, like the first run of them, which I have modded many moons ago with a master volume, bright switch, and standby switch. I don't remember if any of these mods required replacing the original volume pot.

The last time I tried using it, maybe a year ago the volume was really scratchy and would cut in/out, go up wildly if I touched it etc. Now it is just dead.

Is this something I can fix by spraying contact cleaner into it or should I replace it?

Anyone know what I should replace it with and where to get it?

Ok, I realise there's probably a lot of questions here, so I will get a screwdriver and open this thing up and post a pic of it's guts.

Ok, here's a fun one. I did these mods at least 15 years ago and it looks like when I closed it back up I accidentally screwed a hole right through the speaker cable.

Hahaha, class.

I've been thinking of trying to get my hands on my old valve junior head (also the first run) and having a go at modding etc.

Here's the volume pot in question with some context pics. No indication what spec the pot is. Does that say 1? 1MΩ?

Well, looking at the mods now I am pretty sure I never had to touch the original volume pot and it seems to plug in with a wee plug thingy, so if I can find a replacement part online that would be great. If I google it though I just get modding websites.

Ok, this post says it's a 1M volume pot.

http://alt.guitar.amps.narkive.com/R7y ... r-buzz-hum

One of these, maybe?

http://www.allparts.uk.com/products/po ... 1meg-audio

Possibly, but have you tried contact cleaner/exercising it?

I tried turning it around, seems smooth and makes no difference. How to you get the IPA right in there?

I assumed you had a spray or something.

I suppose if you're at the point of scrapping the pot anyway, there's no harm unscrewing it from the chassis and "flooding" it with a q-tip of IPA and a bit of pressure. Should be able to get in round the back, where the lugs are.

Ok, I just watched a YouTube vid where the guy just swooshes the IPA in any old entrance and wiggles the pot around. I'll try that later.

Gavin wrote: ↑Mon Apr 18, 2022 12:38 pm Ok, I just watched a YouTube vid where the guy just swooshes the IPA in any old entrance and wiggles the pot around. I'll try that later.

Yeah, just open up your can/bottle of IPA and pour it into the lil' gap above the terminals so it'll flood the tracks on the pot, and give it a load of turns, making sure you're doing it the full travel.

I'd a heavy-smoking great aunt that if you dropped a boiled sweet on the ground, she'd pick it up, take out her teeth, and swoosh the the sweet around in her mouth for minute or so to get it all nice and clean, then give it back to you, sticky and reeking of Lambert and Butler. You were then obliged to enjoy the sweet.

Could be worth a go?

This is all making me think I should just buy a fancy new solid state practice amp.

Bacchus wrote: ↑Mon Apr 18, 2022 12:46 pm I'd a heavy-smoking great aunt that if you dropped a boiled sweet on the ground, she'd pick it up, take out her teeth, and swoosh the the sweet around in her mouth for minute or so to get it all nice and clean, then give it back to you, sticky and reeking of Lambert and Butler. You were then obliged to enjoy the sweet.

Could be worth a go?

I proper cackled at this

So I skooshed a load of IPA through both the volume and master volume and gave them both a good old wiggle-de-wiggle. Left it until now to dry out and it seems like it's back to life. I think the pots just needed cleaned.

Has a hell of a noisy buzz, but I seem to remember it always being like that. I think people at the time said it was bad PCB design causing it. I think I remember they made it better in subsequent versions.

FFS. Turns out it's not just the amp. It's the amp plus my Jaguar is having some kind of grounding issues. I was think actually that buzz is really too loud to be normal so I tried my Tele, and after fucking about with the now dodgy switch on that, I got it to work and it's way way quieter. So, basically I all my gear was corroding away inside while I neglected it and occasionally strummed it not plugged in.

I unscrewed the jack plate and everything is grounded to the volume pot. I tried touching everything all over the place to see if I could figure out what wasn't grounded while holding onto the volume pot and I realised that putting pressure at an angle on the pot itself, without touching anything, would actually reduce the buzz. So, I have now skooshed and wiggledy wiggled the tone and volume pots on the Jaguar. I may just skoosh and wiggledy wiggle everything I own at this point out of superstition.

clean the contact points with the pots and control plates and tighten up your pots real good.

Supposedly contact cleaner is bad for pots, you're supposed to use tuner cleaner. Electronic shops have them.