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Trace Elliot V300H problem

S

spector29

Aug 30, 2007
46
0
#1
hi all,

Quick question before I take this to a tech, I believe it's a cold solder but we'll see.

Anyway the head when connected to a cab will basically make no noise at all, even after a good warm up so I have to crank it and then thump the E string to get any volume (only quiet) and then play to keep the volume rising or the amp warming up until it's fine.

Problem again is I can knock the amp and it'll basically go back to nothing. Now and again the volume will drop or disappear if I don't play.

Is it cold solder??
What do you think.

Cheers, Matt.
 
#4
#5
Just about anything electronic can be fixed, the bigh question is "is it worth fixing or will it cost less to just replace it?"

Judging from those pictures, the big green component is a resistor, probably a biasing resistor for the output transistors, but there's no way of me giving an exact diagnosis since I can't see the whole circuit. The solder probably isn't the only problem, and might not be related to the problem at all.

Usually those resistors will get fairly warm and discolor the board, now if the board or resistor were black and charred then I'd start worrying.

Anyway, since it would seem that you don't have much of an electronics background I would take it to a reputable music store that has an amp tech and get an estimate. The worst thing you could possibly do is start messing with it if you don't know what you're doing. The least you could do is ruin a good amp, the most you could do is kill yourself from an electric shock. There are large capacitors in there that hold a considerable charge for quite a while and can still store lethal voltages even after days of the amp being unplugged. (no offense intended and if you do have an electronics background, I'm sorry for my last statement)
 
#6
suppose you've got to cover your ass, you can't really say dive in prod things and see what you find.

I definitely believe it's that spot, I'm not very electrical (just cables, input/output jacks and some chip replacement) but looking at that circuit that definitely seems to be the only problem. And would describe at one point getting a weird feedback that remained even when gain and volume were off.


I just bought it second hand and the seller said it had been serviced multiple times by a reputable repairman.

I find it hard to believe after seeing this.
 
#7
spector29 said:
suppose you've got to cover your ass, you can't really say dive in prod things and see what you find.

I definitely believe it's that spot, I'm not very electrical (just cables, input/output jacks and some chip replacement) but looking at that circuit that definitely seems to be the only problem. And would describe at one point getting a weird feedback that remained even when gain and volume were off.


I just bought it second hand and the seller said it had been serviced multiple times by a reputable repairman.

I find it hard to believe after seeing this.
Click to expand...

Hmm, the "serviced multiple times" statement has me wondering. Sounds like an intermittent problem with the amp. There are a lot of components that can go south without any visible indication of failure. While it's quite possible that the resistor could be the only problem, it might not be. Try resoldering the resistor by first removing all the old solder and applying fresh solder. You don't need an abundance of solder on a joint. We have a saying in the US Navy ET world which is, "the solder joint should have a clean, shiny, mirror like, concave fillet free of pits, voids, or blowholes." I teach Miniature/Microminiature electronic repair in the Navy.

Remember this: If you have any doubt about your abilities, bring it to a qualified tech. It's totally up to you if you want to try this or not. I take no responsibility or liability for the outcome of your actions.
 
#8
Thanks Navy,

well I found a local tech only a couple of minutes away,

went in showed him tapped around and it seems the preamp tubes were rooted.
20 minutes, two tubes and $30 later all good.......So far.

Nothing wrong with that resistor in the end or the circuit board. Luckily.


We'll see how it holds up.


Matt.
 

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