Fried Tube Screamer with too many Volts, not get no sound but a hiss... help!

[Hav]

Hey

Built a TS808 from Tonepad,

put the wrong dang power supply in which shows PRI:230v-240v and SEC: 13.5v 500mA.

:-(

How do I diagnose this to find out what ive blown? True Bypass is working. Pedal gives nothing but a hiss when pedal on MAX everything.

None of the capacitors have blown up from the top... they all look in tact (electros only anyway)

Any help would be amazingggg!

tonepad TS: http://tonepad.com/project.asp?id=1

[vigilante397]

Audio probe, check voltages on transistor and IC.

[diablochris6]

This is where the digital multimeter can help you save the day! I would start by getting readings on any ICs and transistors first and go backwards from there. It also would help to make sure the parts in the power section aren't fried.

The audio probe could help you figure out where the signal ends.

[Hav]

ok a little closer listening and actually there is some very very small volume

and i unplugged and plugged it back in and i get half a second of sound (sounds like the volume is getting louder) then just cuts off again to the really really low volume. cant tell if its distorted.

working on IC readings and Q readings now.. will post in a sec

[Hav]

IC

wall: 9.29

8.58    9.29
8.18    8.32
6.18    8.32
0        8.32

q1

0.98     1.41      9.29
9.29     1.38      0.95

what does this say?

[GibsonGM]

Check the cap in your power supply!  The voltages on your inputs look REALLY high to me!  (not biasing right; you have nearly V+ on them).
It's a good bet that cap was rated <16 volts and is junk.    Right side of schematic shows it, the 47u cap between the two 10K resistors. 

Gotta find it on the PCB....I think Vref (Vb here) is the pink line coming from the 47u cap on the LAYOUT, in the .PDF...should be about 1/2 your battery voltage...so see what's up with that cap, and measure your Vb! 

[Hav]

Yep after comparing the Vs from GGG, theirs show that it should be pretty much 1/2 as you said. Will try find this cap and replace. Kinda glad this happened, helping me debug and learn I suppose!

[Hav]

ok placing the 47u did nothing :-(

IC is still showing the same Vs

Should I look at those 10k resistors?

[Hav]

also seem to be getting 5.87 on Vb's

[GibsonGM]

5.87 is probably ok.  If you have that at all Vb points, and 9V at IC, then try audio probing.   Follow the signal path shown in blue on their "Layout" diagram.    There will be a spot where it dies, and you'll know you're close to the blown part!   Do that and let us know what you find...

BTW, are you SURE your power supply was DC and not AC?  The only parts in there I can think of that are sensitive to that level of DC voltage could be caps....unless you also got the supply hooked up BACKWARDS?   Then, I'd make SURE of my power supply, and put a new IC in.

[Hav]

Thanks for your help Mike,

It was a AC/DC 'converter' power supply..

Found the problem, was a blown IC :-(

Replaced with another 4558DD and its all good :-)

what do you mean supply hooked backward?

[bluebunny]

Found the problem, was a blown IC :-(

Replaced with another 4558DD and its all good :-)

Interesting that the opamp was fried.  All the datasheets I have for 4558 variants show that it's good for at least 36V (+/-18V).

what do you mean supply hooked backward?

You should have +9V from the power supply going to +9V on the board.  And 0V goes to GND on the board.  If you swap them over, bad things happen: magic smoke comes out and silence ensues.   

[R.G.]

Was your power supply 13.5V **AC** or DC?

9V **AC** will kill pedals dead, even with reverse protection diodes.

[vigilante397]

Replacing a 4558 isn't a huge loss if that was the only problem. I hooked up the power backwards on a reverb build and fried a Belton brick hands down the single costliest mistake I've ever made on a build.

[GibsonGM]

Glad it was that simple!  Less than $1 to fix       Yes,  connecting the power supply backwards would mean + going to where - should go, on a DC supply, and that is called "REVERSING THE POLARITY".    And it will do the same as R.G. said regarding AC - it will fry things.      AC is composed of BOTH polarities, and that's why an AC supply will fry parts.   

Much of electronics requires the power to "come from one direction"!   Those parts are called "polarized".

I think we've all done the same thing, ha ha!

[deadastronaut]

Replacing a 4558 isn't a huge loss if that was the only problem. I hooked up the power backwards on a reverb build and fried a Belton brick hands down the single costliest mistake I've ever made on a build.

oops!..nasty.

[Hav]

oh wow, yep puts mine in perspective! looks like i got off on an easy one!

Supply isn't hooked in backward, and I havent got the plug I used to fry it with to check if it was definitely DC or AC!

Thanks for the help guys! :-)

[Haze13]

Use protection diodes for this kind of situations. They are much cheaper than any semiconductor...

[GibsonGM]

Use protection diodes for this kind of situations. They are much cheaper than any semiconductor...

+1  if they go fast enough, they're worthwhile.

[vigilante397]

Use protection diodes for this kind of situations. They are much cheaper than any semiconductor...

+2
Definitely learned my lesson the hard way on that one.