Circuit testing

[mahrous]

ok, so i am wiring my second bass but for some odd reason no sound comes out.

this is the simple Jazz wiring schematic V/V/T. I have used it many times before and it worked from the first time. this time its not working. no sound whatsoever whether hum or buzz.

the only thing i can think of is that it has bad pots (bought from Stewmac). How do i test and find out which pot is not working correctly and all that? yes, i have a multimeter for resistence, current, circuit testing and all that.

thank you!

[luknfur]

Originally Posted by mahrous

ok, so i am wiring my second bass but for some odd reason no sound comes out.

this is the simple Jazz wiring schematic V/V/T. I have used it many times before and it worked from the first time. this time its not working. no sound whatsoever whether hum or buzz.

the only thing i can think of is that it has bad pots (bought from Stewmac). How do i test and find out which pot is not working correctly and all that? yes, i have a multimeter for resistence, current, circuit testing and all that.

thank you!

FWIW:

Digital meter have no clue. For one with a swing arm, just put alligator clips to the center and outside pot lugs and clip the other ends to the meter probes, put the meter on RX1K, and rotate the pot. If the swing arm moves in accord with the stem rotation, it works. If it doesn't, you've probably got a bad meter connection. Chances of more than one pot being bad at once is a long shot. Then swap the outside lead over to the other lug and repeat to test all 3 lugs. Do that on each pot.

The high probability shot is flawed wiring.

In my recall, you were also making your own pups. If these are some, do the same thing with the meter on the pup coil start and finish leads with pup wires disconnected from the pots. If you get no arm swing on the meter - pups have a short.

[bill h]

Look for a ground

[mahrous]

i highly doubt its flawed wiring. i have wired many basses before using this exact same schematic. i have matched in reality to my other bass that i wired last week. identical wiring techniques and all.

i got no swing arm any other suggestions before i start removing solders and do trial and error?

[luknfur]

Originally Posted by mahrous

i highly doubt its flawed wiring. i have wired many basses before using this exact same schematic. i have matched in reality to my other bass that i wired last week. identical wiring techniques and all.

i got no swing arm any other suggestions before i start removing solders and do trial and error?

FWIW:

I've wired plenty myself yet do it all the time. This is not the bass you wired before, apparently that one works, this one doesn't. If you get no swing on pots, they don't work - or you have a bad connection. If you just touch the meter probes together and the arms don't swing, then the meter's not working (unless the meter is incorrectly set). If they do, it is.

It's possible more than one pot is bad, just highly unlikely.

If there's one thing you don't want to do in trouble shooting, it's assume anything. Everything is wrong to demonstrated to be otherwise. Otherwise you're not trouble shooting, you're guessing at random.

[Audere]

[quote=mahrous]no sound whatsoever whether hum or buzz.
QUOTE]

Remove the output cable.
Rotate both vol pots to 0.
Measure the resistance from the jack hot to the jack ground.

The value should be approximately 1/2 the value of the vol pots resistance. Make sure the tone pot has no effect when it is moved to a new value (since it is AC coupled it will not be "in the circuit" for a DC resistance measurement).

Turn one of the vol pots to the max. The resistance should now be approximately the resistance of 1 pickup (1k to 10k) to ground.

Turn the first vol pot back off.

Test the 2nd vol pot the same way.

I suspect the first resistance reading will be very low as you probably have a short to ground.

[Geoff St. Germaine]

Test your pots.