Problem With Digitech Whammy IV Pedal

fair.child · October 21, 2012, 09:26:29 PM

Hi folks,

I've got problem here with my whammy pedal. Okay let's make long story short;

1) I've got this pedal from ebay, broken, for 50 bucks.
2) The pedal came in dead, and I've tried to fix it, then it worked for me.
- What did I do ? I changed the 1N4005 Diodes to 1N4007 near with power supply and yeahh it was working
3) Then I haven't turned up the pedal for a while (during a week, probably 3 days), and I went practice with my bad, then there was technical difficulties with this pedal. I've used same power supply like I turned / tested it before, but hey, my pedal didn't work with me.
4) I've got whammy signal, but it was really small signal, it is more likely no sound at all, but when I pressed the momentary switch, I've got boost up signal from my guitar through my amp
5) I was back home tried to open the box again, and I touched the 1N4007, it was really hot. I've tried to change 1N4007 again and the result is still same until now.

Note:

I've tried to calibrate the pedal, nothing works
Before I started to fix this pedal, I took a look to this thread http://www.diystompboxes.com/smfforum/index.php?topic=82383.0

My question is, How do I make this pedal works again ?

Thank you

pinkjimiphoton · October 21, 2012, 11:43:07 PM

i'd replace those diodes, make sure there's no short somewhere. it SHOULD get "warm" while running.

make sure you power it with a 9vac 1500ma power supply only. it really needs the power, or it will overheat.

if there's a regulator, i'd check it to make sure it's good.

also open it up and make sure nothing is shorted to the case, etc...these things are generally either good or dead, and if you resurrected it, should be something stupid...check the solder joints on the input for the power jack, and also the input/output jacks to make sure they are well-soldered to the pcb.

i gotta hack if ya get it going so you can make the presets go up and down with an auxilliary footswitch..it's cool, you don't have to bend over and can scroll from preset to preset. good luck.

MarcoMike · October 22, 2012, 07:59:27 AM

I had one with faulty ferrite bead close to the output... try following the signal with an audio probe and see where it stops...

fair.child · October 22, 2012, 08:55:45 AM

Quote from: pinkjimiphoton on October 21, 2012, 11:43:07 PM
i'd replace those diodes, make sure there's no short somewhere. it SHOULD get "warm" while running.

make sure you power it with a 9vac 1500ma power supply only. it really needs the power, or it will overheat.

if there's a regulator, i'd check it to make sure it's good.

also open it up and make sure nothing is shorted to the case, etc...these things are generally either good or dead, and if you resurrected it, should be something stupid...check the solder joints on the input for the power jack, and also the input/output jacks to make sure they are well-soldered to the pcb.

i gotta hack if ya get it going so you can make the presets go up and down with an auxilliary footswitch..it's cool, you don't have to bend over and can scroll from preset to preset. good luck.

I did the same thing like what you have done before, however, it seems look like the problem comes from LD1117V33C. I putted order last night with mouser and I'm waiting for the item now. I wish that's probably the problem came from.

Solder joints on the input and power jack, also i/o jack they are properly soldered to pcb. I've already doubled checked that with VOM continuity and seems perfect. I've tried to let it go for a while, since I'm waiting for 3.3V regulator and nothing much to do now.

@MarcoMike,

What kind of ferrite bead is that ? I don't know what type of inductor that Whammy IV uses. Would you mind to explain that ?

Thanks all, I appreciate your help and advices

pinkjimiphoton · October 22, 2012, 10:46:20 AM

ferrite beads are passive. all they are is little magnetic tubes with wires thru them, they're only functions is rfi suppression, they have no other effect on the circuit or tone in any way.

charmonder · November 26, 2012, 06:12:59 PM

but do you all think it is okay to use 1n4007s in place of the 1n4005s? I have a whammy iv is doing the thing where it only lights up for a half second and then turns off, which I've heard is just an issue with the power section.

pinkjimiphoton · November 26, 2012, 08:49:29 PM

yah, 1n400x are all probably close enough for rock and roll

charmonder · November 26, 2012, 10:45:14 PM

awesome! worth a shot then.

pinkjimiphoton you are the king of DIYstomp

pinkjimiphoton · November 28, 2012, 04:42:46 PM

more like a pauper or a jester or something low...lol

MoltenVoltage · November 29, 2012, 03:52:36 AM

Try swapping out the power input caps - just make sure you use ones with the same uF and at least as high of voltage rating (and polarity correct!).

I've fixed more than one that way.

Also replace the rectifier diodes if you've cooked them already.

+1 on using the right power supply.

If you want to switch programs easily we have a simple kit for that:
http://www.kaom.com/PedalSync_One_Trick_Pony_MIDI_Data_Module_KIT_p/module_007.htm

pinkjimiphoton · November 29, 2012, 01:05:36 PM

if ya get it running, and want a hack to remotely change the presets via a pair of footswitches, let me know. you would have to drill one hole in the chassis and add a couple inches of shielded mic cable and a trs jack. it's a pretty easy hack.

if you wanna keep it stock, check out moltenvoltage's fine products tho like the molten midi pedal...some of their stuff is absolutely amazing! and programmable. pretty sick!

MoltenVoltage · November 30, 2012, 07:34:38 PM

Thanks for the props!

That hack was actually the first original mod we came up with, but stopped offering it after Molten MIDI. Basically just short the encoder with a SPST switch.

It's pretty consisent on the 4, never tried it on the 5. Keep the wires off the PCB as much as possible.

It's also fun to add a Blend Control - check out the vid:

I'll be surprised if the cap swap doesn't work.

pinkjimiphoton · November 30, 2012, 08:37:02 PM

well deserved props!!
if i could afford it on my bottom feeder salary, i'd own one!

the hack i came up with uses two momentary footswitches, a spst and a dpdt. you wire 'em to the switch (i have a whammy 4) and put it so one switch is just the two connections to the encoder/pot, and the other is in parallel but backwards. then you can go up/down independently instead of one way or the other.

even easier, two spst momentarys...choose one for up, and step on both for down. either way. adds a bit of versatility.

i am gonna check out your blend video, thanks for the link!! sounds like it would be a worthy addition... you need a daughterboard to buffer it i'd imagine?

just watched the video...that's f'n sick!! well done!!

that said...if changing those caps works for the OP, i highly reccomend they try the molten midi. if you're gonna really use these things, i think it's a must.

i don't use mine live, it seems to cause too much RFI for some of my fuzzes, and leaves an annoying noise when the guitar's all the way down...rfi, hash...i dunno what. sounds like an old computer modem dialing.

MoltenVoltage · November 30, 2012, 10:01:23 PM

No daughterboard needed, just lift the tip on the Dry Out and run it and the Wet Out to the outer lugs of a B10K pot and you are off to the races!

I make it switchable in and out - but if you have it off, you need to turn the pot all the way to Wet or you will lose some high end. You don't necessarily need to make it switchable as you get 98% of the signal when the pot is full Wet.

You need to do the True Bypass first so you go directly to the output jack with the mix.

As far as RF goes, keep it at the front of the signal chain and drop in the true bypass or make a loop box. As long as you use the right P/S and keep it out of the signal chain when you aren't using it, you shouldn't have much of an RF issue. You can also make a Blend box - I've seen some for sale on ebay already. No surgery required, just mix the Wet and Dry outputs. The 2 octave up harmony is king size!

pinkjimiphoton · November 30, 2012, 10:55:24 PM

wow, thanks, that's so absolutely cool of you to share this info with us all bro!!!
righteous as the day is long!

i didn't TB mine, was gonna but then figured for the amount i use it it probably wasn't worth it.
i do have a loop box i built tho...maybe i'll try that.

i've tried mine at the front of my chain (my fuzzface hates it's buffer, so i guess TB would definitely help there) but i think it sounds better (tho doesn't track as well) after distortion.

i have the proper power supply, so i'll re-visit it...i really appreciate the info! now as soon as i get a chance to get back down with the sickness (solder....mmmm....) i've got a project to try.

again, i gotta hand it to you for being so generous with the info!

namaste...

Yauhen · February 03, 2015, 09:48:57 AM

Hi there!
I have a problem with my Whammy IV
Phototransistor is broken

I do not know his brand / model !
I need help, please write the model of phototransistor so that I can replace.
thank you

pinkjimiphoton · February 03, 2015, 12:16:32 PM

hey man, welcome to the forum... no idea what kind of phototransistor is in there, i'd imagine brand shouldn't matter tho

Yauhen · February 05, 2015, 11:28:29 AM

I found information on the transistor

I think it is LPT80A.
Is that correct? Thanks!

Govmnt_Lacky · February 05, 2015, 11:32:09 AM

Quote from: Yauhen on February 05, 2015, 11:28:29 AM
I think it is LPT80A.
Is that correct? Thanks!

Same one used in the XP series pedals.

Yauhen · February 06, 2015, 05:23:36 AM

I have usually Whammy IV. I'm sorry, but I don't know what is the XP series

Can I put this phototransistor inside my Whammy?

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Problem With Digitech Whammy IV Pedal