Broken Whammy - where to start?

[yeeshkul]

I have a broken WH1 to repair. The sound goes through but there are no changes in the sound when the pedal is moved. Where would you start to look?
The LED diode that shines on the phototransistor is ok, that is all i know now I don't give myself much chance to repair this monster, but once i've opened the lid ... i wanna give it a try.

[yeeshkul]

The phototransistor seems to be ok - it sends voltage in dependence on the pedal position.

[space_ryerson]

Do the harmony settings still give you harmonies? That would indicate that the functional aspect of the pitch shifting is still working.

[Quackzed]

I've read somewhere that these things have a tendency to short out by the pcb touching the box, remedied by using some electrical tape wherever the pcb is near the box, or taping up the pcb here and there. check out the board and how it's held to the box, see if anything is making contact to/ touching or too close to the enclosure?

[yeeshkul]

The rotary switch doesn't work. Isolation should be ok, i have just loosened a bit the PCB and no change .
Also i checked the voltages on the voltage chips 7805CT, one gives +5V, which is ok,  the 7908CT -7.9V, which is fine as well.

[Gus]

I have not worked on a WH1.  I would look for the calibration for the WH1.

found this with google
http://www.thegearpage.net/board/archive/index.php/t-511480.html

[yeeshkul]

Thanks Gus, they say the WH-1 calibration is automatic as you full-sweep (at least that's what i've googled out).

The summary of the things I've found out so far:

A. Behaviour
1. No response to the sweep
2. The rotary switch doesn't work all around with a little exception - in 2 positions i can hear a little change in the sound but not what it is supposed to do

B. Repair progress
1. No shortages
2. The LED in the optical control and the phototransistor are ok
3. BUG: The power supply gives the right voltages, although one thing is weird - the input voltages to the power chips differ (!) and i don't think they should differ.
The input voltage of the power chips should be like:  (9-0.6)*1.4=11.7V, however the 7908 gives -12.7V (= 9*1.4 => the diode is screwed up).
The output voltage of 7908 is -8V however. Can the bad diode be the cause of any troubles then?
The terminals seems to be a bit burned, but 7805 heats a lot (that one is being fixed to the enclosure to keep it cool). 7908 is much cooler and it is not being helped to stay cool anyhow. I suppose the previous owner used a bad supply and gave it some harsh times.
4. BUG??:The sound goes through, but it is permanently distorted (i have never played any Whammy, so i don't know if this is all right or not). Also there is a little noise in the background - the kind of noise bad transistors produce in a simple analogue circuits i have been dealing with so far.

The power supply situation:

[Rectangular]

try replacing the regulators. also, make sure that your wall wart is outputing the right AC.

[yeeshkul]

The wallwart i got with this is 9VAC, 1200mA intended for Line 6. I guess that is ok. Yeah, i can't do anything now but change the power side.

[R.G.]

The wallwart i got with this is 9VAC, 1200mA intended for Line 6. I guess that is ok. Yeah, i can't do anything now but change the power side.

I'm not much help with fixing the whammy insides, but do notice that plugging that 9Vac adapter into any other "normal" pedal will kill the pedal dead. And it will do so even if the pedal is "protected" from reverse voltages by a reverse diode.

[Gus]

The DC voltages look like they might be correct.  They are using AC to a voltage doubler type circuit and  using the floating center node as ground.  The input to the regs is different because of different current usage on the +- I would guess.

Can you check the power supply with a scope? you can still be having a power transformer issue.  Sometimes DC will look good with a DMM but there can be ripple and that can cause problems.  What is the correct transformer rating?  How many VA and voltage and current?

Is this the first Whammy model?

I would not blindly change the regs or other parts.  First get a correct transformer then if it still does not work and you have PS ripple check the caps before the regulators

9VAC might be too low for the -8 VDC reg.

[yeeshkul]

Yes, it is the first Whammy, WH-1. The bottom lid says that the power requirements are 9VAC/750mA. The Line 6 adapter i am using is 9VAC/1200 mA. I measured the output (open loop) with DMM and it was 10.3VAC, which is about what i was  expecting.

Too bad i have no scope, i would expect PS ripple on a low VA tranformers feeded to a high current draw input - is it right?. This one seems to have enough VA judging by the 1200mA, but who knows ...

I can post here some pictures.

[mrscientificterms]

I love my original wh-1, have had it for many, many years w/out issue.  I would be super bummed if it died, and could never afford to replace it.  In your quest to fix yours, did you come across a schematic?  I have never been able to find one.  I hope you get yours fixed.

[blanik]

i have one of those here and it needs 12 V AC ... 

[Quackzed]

i found this on hc review,thought it might help... maybee there are a few different versions?

Now here is the reason why I'm writing this review. The whammy WH-1 will only sound right, work right, if it has the correct power supply. It's kind of a mystery to find out if you do not have the original adaptor. The manual for the WH-1 says you need a special 10 volt Adaptor, yet an "original" Whammy wh-1 adaptor says the output is 9 volts. In fact they are both "wrong"! The actually voltage the WH-1 needs is 9.6 Volts, not 10 or 9. The original Whammy WH-1 adaptor that ""states 9 volts"", really is a 9.6 volt adaptor! I called Digitech and got the info straight from them. Only the model PS750 adaptor will make her function right. Now here's the problem. People see 9 volts as the stated output on the original adaptor and think any digitech 9 volt adaptor will work. Yes, a regular 9 volt will turn the thing on and kind-a work...but not with exact accuracy. And this maybe one reason why people give The WH-1 a bad review, and say it's "really" close to the reissue. Well it's not. The reissues is a toy, plane and simple. The original WH-1 with correct power supply is a professional piece of equipment.

[yeeshkul]

Here is the complete WH-1 schematics guys
http://www.hoho.cz/osobni/wh1.pdf

When you look at the picture above (the power side), you can see that they take the unregulated AC (marked as -V REG, but barely readable) right before 7908. That may be the problem as well. If you guys find where that power goes on the schematics please tell me. That may be one of the problems ...

The person who you quoted measured apparently 9.6V right on the power supply (open loop). That is interesting fact because I would expect a higher open loop voltage on lower VA transformer (i measured 10V on 1200mA where the original is designed for 750mA). This actually can mean that the 9.6 is somehow necessary.

[yeeshkul]

But i am not familiar with the digital technologies, so i am just guessing ...

[Tonmon]

Hi sorry to resurrect an old thread. I need to replace the rotary selector pot on my WH1 anyone know what part I should order from Mouser or someplace similiar?

[thelonious]

For the Whammy IV, it is Digitech encoder # 44-0114 ($2.12 straight from Digitech at 801-566-8800). I don't know about the WH1; you can ask them if it is the same part or not. Or use their contact form at http://digitech.com/en-US/support to ask.

[Tonmon]

Hi Thanks for the reply and help. I already mailed Digitech but they could only send me the schematics for the WH1 and said they no longer do parts for WH1 was hoping I could source one on Mouser or somewhere similiar but just don't know what specs the encoder needs to have. I have a Whammy IV must have a look inside but have a feeling its different as encoder on WH1 feels different when moving.