Hey Guys,
I just bought a vintage Mad in Italy V846 Wah for a REAL BARGIN price at a flee market(!!!) but... in doesn't wha... when I turn it on it sound like whe all the way to the bass side and rocking the padel doesn't change the wha range... a real bummer
I tested it a bit a bit and found a couple of things:
1. the pot shows zero ressistance when tested properly but when I tested only the 1 and 2 lugs it showed full resistance.
2. With a 9.20v batt ALL of the transistors legs had +8.86v and so did the ground...

what does all of that mean???

Please help, I can't wait to here that vintage vox vibe already!

Tahnx ahead,
Dan.

Option1:
make sure the inductor is ok, salvage it, and strip the board. Get new components (smallbear) including a pot and build the whole thing from scratch with the original inductor. It's not too hard, it's a simple circuit.
This method is probably quicker than figuring out what's wrong.
Option2:
I have a feeling there's a mistake in your  measurements I'm afraid - the battery is directly connected (or should be) to ground with it's - pole. So IF the wiring is correct (CHECK!) there's no way ground could have any other potential than 0V.
Verify that the input jack ISN'T stereo (powerswitching). If it is, insert a jack into the input and measure the voltages again.
I don't quite get what youre saying about wether it's working or not, but apparently it does work but is stuck on one side of the throw? Take the pot out of the circuit, and remeasure. If it doesn't respond, replace (probably a good idea to do this anyway)

I would take a look at the bottom of the PCB, if there are messy areas, this may explain the strange voltages found at Pins of the transistors.
 I suspect there may have been an error in the readings somehow, that so many of the measurements would come out like this seems unlikely unless somhow a bunch of 'extra' connections were somehow made by accident.

you did rock the pot away (or towards) from you when you tested it didnt you? or did you test lugs 1 and 3? the voltages seem alright. if you measure from v+ to ground its the same as measuring from the + to the - on the battery. maybe check the inductor and the cap near it.

good luck
Jim

Quote2. With a 9.20v batt ALL of the transistors legs had +8.86v and so did the ground...

The ground is open somewhere. None of the transistors is getting full voltage. Track this down by clipping a voltmeter lead to the battery (-) lead and following the wire. When the voltage jumps from 0V to 8.86, you've found the break.

Quote1. the pot shows zero ressistance when tested properly but when I tested only the 1 and 2 lugs it showed full resistance.

Test the pot this way: measure the two outside lugs for full resistance - about 100K. Then clip your ohmmeter lead to one outside lug and the wiper. You should be able to turn the pot and see the resistance change more or less smoothly from 0 ohms at one extreme to full resistance a the other. If it suddenly goes to infinite resistance anywhere, you have an open place on the pot.

Now you know why its a  REAL BARGIN price.....

These pedals are easy to fix, just take your time, there's not alot to them, but they're worth ALOT of money working, and they sound better than anything else you'll come across...

Don't ditch the original components, if your inductor is working it's probably a bad transistor or one of the .22 caps...also, check both of the paper .01 caps, especially the one at the input, they dry up and very often (but not always) need to be replaced...

 Ditching all of the original components when it's probably just one makes absolutely no sense, but if you do decide to destroy the board and put new components on it, PLEASE sell me the originals

hmmm thats funny, i thought the voltages looked ok. the voltage from the battery to the V+ rails always seems to differ a little, but i admit the voltage in questions were a little more off than usual. and i always measure the v+ voltage from v+ to ground... do i know what im talking about?

learn something every day.

cheers
Jim

If there's no "wah", and just acts like a volume pedal then the electrolytic cap across the inductor is dead. Replace it with a 4.7uF/16V cap.

If there's no "wah" and just the treble changes then 99% odds-on the inductor is dead. Bummer. Fasel inductors cost mucho, and you just cant get the originals at a reasonable price.

To test the inductor you can use the 500mH primary of an audio transformer as a swap-out. Good luck.

You can also measure with your meter on low ohm setting across both leads of the inductor, in curcuit...the metal can inductor in an Italian Vox 846 should read 15-18 ohms...but they rarely fail...somtimes the solder connection is bad and you need to re-solder but don't heat it too long or you'll blow the inductor...

Did you test the little paper .01 caps??

First of all, I wanna thank ALL OF YOU guy for helping out...
I'm currently away from my little workbench and pedal, but I will do all of the mesuerements and testing requierd.

Some detalis about this unit from what I've checked:
It's seems to be '67-'68 italian made Vox V846. the idnuctor is a a Halo type and the trannies are (haven't been able to identify the exact models yet) 1st- metal can type, 2nd- black dome-like type.

all other part look original and the unit is in pretty good shape, mechanical-wize. It cost me about $55, and I took without a question (the enclosure itself cost more than that today )

QuoteIf there's no "wah", and just acts like a volume pedal then the electrolytic cap across the inductor is dead. Replace it with a 4.7uF/16V cap.

If there's no "wah" and just the treble changes then 99% odds-on the inductor is dead. Bummer. Fasel inductors cost mucho, and you just cant get the originals at a reasonable price.

There is a Wah sound - but only a fully bass position wah sound, and rocking the pedal dosen't afeect the frequency... tha's why I think it's a bad pot.

Iguess I'll do some more testing and post right after that.

Again thanx guys

Regards,
Dan.

You've got an Italian Clyde McCoy there...I'm not a fan of the halo inductors personally but some people like 'em...either way the pedal's worth alot...I forgot to mention that you should check and see if the pot is wired up incorrectly, that would make the problem you described...a bad cap would as well...just swap them out one by one and you'll find the problem, but double-check all wiring first...