#1
Alright, so I have an old(er) vox vt modeling amp ( i think thats the model) and anyways I was thinking about fixing it because it always was useful for home practices and what not.

I'm about 99 % sure there is just a broken or loose solder joint between the input jack and wherever it connects to. Just the fact the it started out as a crackle and now full on doesn't make sound unless jiggled around. Also, no dirty pots as i cleaned them all. Anyways I know my way around a soldering iron, however I know there are definitely deadly charges in amps. I was wondering what exactly to watch out and be careful of when fixing this. Any descriptions or pictures would be greatly appreciated. Thanks guys.
#2
id be careful not to touch any capacitors especially the big ones
Gear:
Marshall haze40
Yamaha GA15
Line 6 pod GX
Ibanez PGM301
Yamaha self customized EG012
Jackson KVX10
Boss DS1
GE 7
BD2
CS3
Vox satchurator
Home made TS808
Belcat delay
#3
if you're gonna have a look around because of "deadly charges" how bout you just unplug it? then there's no deadly charges!

and what you should look for is loose wires, sort of ones that don't match the rest.
Belief is a beautiful armour but makes for the heaviest sword.
#4
Quote by Dempsey68
if you're gonna have a look around because of "deadly charges" how bout you just unplug it? then there's no deadly charges!

and what you should look for is loose wires, sort of ones that don't match the rest.


Don't capacitors hold charge even after being unplugged?
#5
Quote by Dempsey68
if you're gonna have a look around because of "deadly charges" how bout you just unplug it? then there's no deadly charges!

WRONG, VERY WRONG. The filter capacitors hold charge even if everything's unplugged. They need to be drained properly before you can work on the amp without worry.

TS, DO NOT GO POKING AROUND IN YOUR AMP IF YOU DON'T KNOW WHAT YOU'RE DOING.
#6
Quote by NakedInTheRain
WRONG, VERY WRONG. The filter capacitors hold charge even if everything's unplugged. They need to be drained properly before you can work on the amp without worry.

TS, DO NOT GO POKING AROUND IN YOUR AMP IF YOU DON'T KNOW WHAT YOU'RE DOING.

I've been zapped by 230 Volts... ...ONCE trust me it wont happen again always been working perfectly safe since then
Gear:
Marshall haze40
Yamaha GA15
Line 6 pod GX
Ibanez PGM301
Yamaha self customized EG012
Jackson KVX10
Boss DS1
GE 7
BD2
CS3
Vox satchurator
Home made TS808
Belcat delay
#7
oh ok my bad, SORRY IF I KILLED TS!
Belief is a beautiful armour but makes for the heaviest sword.
#8
http://en.wikipedia.org/wiki/Capacitor

There are a few pics of what caps look like.

Make sure your amp is unplugged. Find a good ground (metal water pipe, etc.) and attach an adequate length of wire to it. Touch the wire to the electrical terminals and body of any component you plan on handling. Have a blast learning some electronics!

As a general rule of thumb, the bigger the cap the more energy/charge it could potentially retain. If the amp is a smaller wattage solid state, the caps probably aren't very big and not much to worry about. Just ground them, and don't do any repairs standing in a puddle of water with bare feet.
#9
You could use the resistor method to drain the caps.
Put a resistor in parallel with the cap.
I used a 200Kohm resistor(I used to 100K in series because that's what I had lying around at the time).
Try to get the highest value of resistor available in the store. Higher resistance=quicker draining.
Just put a voltmeter in parallel with the cap and drain it with the resistor untill it is done.
If you are really paranoid, you can wear rubber gloves. These will isolate you somewhat(not 100%).
While you are inside the amp, you should clean it up. Remove any dust with compressed air, clear out any spiderwebs(My amp once had a Brown Reclusive living in it. I guess he got fried when I turned it on...).

One trick I use to drain the caps a bit so they aren't at full volts:
Unplug the amp, then turn it on for a bit. This should drain some of the charge. Not enough to put it at safe levels, but I'd rather have 150 volts running through me than 350 volts.
..I was watching my death.
#10
Quote by Dempsey68
if you're gonna have a look around because of "deadly charges" how bout you just unplug it? then there's no deadly charges!

and what you should look for is loose wires, sort of ones that don't match the rest.

Nice atempt at trying to look smart. anyways other than this guy, thanks for the recommendations and info!
#11
Quote by Fender/marshall
Nice atempt at trying to look smart. anyways other than this guy, thanks for the recommendations and info!


He was only trying to help you, there's no need to be a douche about it

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#12
^yeah, you dont have to be a douche for someone giving you deadly advice

And TS, chill out not like you died.

Cheers!
#13
Quote by Led_Head_1990
He was only trying to help you, there's no need to be a douche about it


I wasn't? It was dumb advice. I already knew that unplugging wouldn't make it safe, so who is he to come into a thread and give misinformed advice? Whatver haha irrelevant.