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Picked up a broken Whammy 4, hate myself.

Started by AntKnee, October 08, 2014, 07:15:08 AM

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AntKnee

Quote from: wgc on October 16, 2014, 05:10:52 PM
It's not ac, rectification happens on the pcb shortly after the power jack.

As far as I can tell you haven't ruled out all of the other possibilities already posted. Very likely your issue can be one of those.

You're right. I have verified continuity to ground. I need to check the regulator voltages. I assume then, that I just test it like any other voltage, then?
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

#31
(numbering the leads 1, 2, 3, from left to right as pictured)

U1 (LD33V):
1. (G)
2. (O) 3.30
3. (I) 10.17

U2 (MC7805C):
1. (I) 12.33
2. (G)
3. (O) 5.02

U3 (KA7905):
1. (G)
2. (I) -14.20
3. (O) -5.02
I build, and once in a while I might sell, pedals as "Vertigo Effects".

wgc

You'll want to check data sheets for each, but 3.3v and 5v seems ok to me on a digital circuit.

Get the data sheets for the other ics and check voltages there too.
always the beautiful answer who asks a more beautiful question.
e.e. cummings

AntKnee

Quote from: wgc on October 17, 2014, 06:46:38 AM
You'll want to check data sheets for each, but 3.3v and 5v seems ok to me on a digital circuit.

Get the data sheets for the other ics and check voltages there too.

If those numbers are good, and the problem isn't with the power, and it is possibly an IC, then this is where I throw in the towel and trash it. These ICs are tiny and I don't even want to mess with trying to un/re-solder 144 microscopic leads to a board. I don't have the tools for it, anyway. I'll check some of the easier looking ones and post them up, but I've just about reached my limit.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

wgc

It could be something in between power and ics. Likely something easy
always the beautiful answer who asks a more beautiful question.
e.e. cummings

AntKnee

Quote from: wgc on October 17, 2014, 08:38:19 AM
It could be something in between power and ics. Likely something easy

True. I really appreciate your, and everyone's, time and help. I just miss easy problems, like I forgot to put the IC in.

Question: What should I look for on the data sheet? Am I looking for in and out pins to check voltages?
I build, and once in a while I might sell, pedals as "Vertigo Effects".

Govmnt_Lacky

One thing I wonder is why the 3 different input voltages to the regulators?

Anyways... could you post the part numbers for the ICs? Doesn't hurt to have other eyes looking for info  ;)

AntKnee

Sure thing. Thanks, gentlemen.

U4, U5, U7, U14:
   4580
   0236
   JRC

U6:   CS4221-KS
   JNADPC9934

U8:   74HC4053
   908944

U9:    72-5530-01 V120
   WHAMMY4
   CS-DA4A   

U10:   (MOTOROLA)
   XCB56362PV100
   OH76G
   HQCZ9950

U11:   93C46B
   /SN

U12:   00005
   6N138

U13:   IL74HCCUD
   C5836ME
   Hnn9931D

U16:   9918H
   74HC574A
I build, and once in a while I might sell, pedals as "Vertigo Effects".

AntKnee

Quote from: Govmnt_Lacky on October 17, 2014, 12:55:41 PM
One thing I wonder is why the 3 different input voltages to the regulators?

Anyways... could you post the part numbers for the ICs? Doesn't hurt to have other eyes looking for info  ;)

I wondered the same thing. There is a chain of rectifiers (1N4005E and two large ones with no marking) and 1000uF caps between the power jack and the regulators.
I build, and once in a while I might sell, pedals as "Vertigo Effects".

Govmnt_Lacky

Something else you could try is to simply email Digitech support and "ask" for the schematic to your pedal. They are usually very forthcoming with that info (as long as they do not currently sell that model)

Worst they can do is say NO  8)