5E3 serious crackling

[wcrankshaw]

My 5E3, newly built, was making some slight crackling when playing open low E string. within an hour of this observation it is now crackling loudly quite a bit even without a guitar cable plugged in. If I touch anything it pops, crackles, or even sounds like really loud static that you might get out of a radio. Any idea what the heck is going on?

[wcrankshaw]

UPDATE - If I blow air across the open chassis it causes crackling, and weird feedback sounds. Also if I tap on the table it's sitting on. I've swapped out the preamp tubes and it made no difference.

[captntasty]

Have you tried the "chopstick" test? I'd see if there isn't a loose connection/bad solder joint somewhere first.

[wcrankshaw]

I have. Unfortunately literally everything produces crackling, popping, and extremely loud static. I'm sort of at a loss. I can tap on the table it's sitting on and loud pops/crackling come through the speaker.

[Steve Conner]

You've forgotten to solder one of the joints in there, go back and check them all.

[wcrankshaw]

Even though it worked beautifully for about the first 2 hours of operation? I checked all the joints and hit several of them that looked potentially spotty with an iron.

Also swapped the preamp tubes all out and it didn't fix it. Could a power tube cause this?

[wcrankshaw]

I should also add that when any, but the high E string is strummed now there is an accompanying very bad distortion.

[ThermionicScott]

Did you use carbon comps? Perhaps one of the plate resistors is bad.

[wcrankshaw]

I did. Are you thinking it might have been a not so good resistor, and a couple hours of use nuked it?

[ThermionicScott]

I did. Are you thinking it might have been a not so good resistor, and a couple hours of use nuked it?

Could be. And I've had some that were just noisy from the get-go, even though they measured relatively close to what they were supposed to. I would try tapping each one REALLY gently with a pencil eraser, and you might be able to find the offender without shaking all of them. Can you still hear the crackling with the volumes turned all the way down?

- Scott

[JHow]

Even though it worked beautifully for about the first 2 hours of operation?...

As weird as it sounds, I have seen unsoldered joints in old radios that came that way from the factory. The component was wrapped on a lug, never soldered, and went to market that way. Sometimes it can work for decades like that.

And then the cold solder joint on my 1990s chevy S-10 windshield wiper controller worked great when it was warm, but would turn off when it got cold, like in the middle of a rainstorm.

But, back to your problem, it really does sound like a joint (no not that) issue.

[wcrankshaw]

Crackling occurs with volume all the way down, nothing plugged in, and not touching anything. Like I said I can tap the table it's on and it sounds like an explosion is occurring. Every single component makes noise with gentle tapping. This is really pretty weird.

[JHow]

If it's arcing, then it something in the high-voltage areas of the circuit. I take it you haven't observed any sparks flying? No carbon on the sockets? You can try turning off lights and observe in darkness (touch nothing!). Could be plate Rs as you noted, could also be cathode bias resistor, like the 250-5w, that can get hot and de-solder itself and or create cold solder connection.

In your picture in the other post, it looks like your ground on your three wire plug is tied to your ground buss - that three-wire plug ground connection really should have it's own separate ground bolt to the chassis. That won't cure your popping, but it brings up the question of how the large copper buss wire is secured. It looks like one end of the buss wried bolted with a green bolt to the chassis? Is the other end of the bus wire secured to anything else mechanical?

[wcrankshaw]

Yeah, no arcing, just crazy noises. Should tapping a filter cap on the outside surface, with a wooden spoon, sound like it's being discharged?

I guess I'll just have to resolder everything and hope for the best. There aren't any dull looking solder joints, but I don't guess that guarantees there isn't a cold solder. On a more technical note, if the lead of a component is solidly embedded in solder but might not be touching the actual turret, does that constitute a cold solder? I don't know of any where this is the case, but I suppose underneath the solder this could be occurring somewhere.

[JHow]

Not sure on your question about wooden spoon and filter cap. Just about every component can be somewhat microphonic and amplify physical tapping.

Re solder joints, its best to have a mechanical connection, if inserted lead in top of turret, it should be touching turret. One thing I have done with turrets when repairing installed board is to heat turret and have the old solder run out the backside. Sometimes you end up with joint that looks okay on the top, but is dodgy underneath.

Truth to tell, I don't like turrets overly much, and I prefer to wrap on the turret, and have only one item inserted in turret.