Superbolt Issues

[Ncuab]

So I've built a few Superbolts and with half of them when I put power to it, either the IC chip starts to smoke or one of the caps explode.  Anyone else having issues like this?  I get most of my parts from Tayda as well.  Is it their IC chips?  Is it my wiring?

[Neil mcNasty]

Defenatly a wiring/solder issue!
Short circuit or wrong polarity!
Check component placements for mistakes.
Sounds like it is centered around the chip, and then we are talkin power section/charge pump area.
Specially check orientation of the diodes and the polarity of the electrolytics.
If everything looks ok, and is in it's corrct location...
Reflow solder and cut/scrape between the gaps.
Usally helps...

[induction]

Questions:
1. What charge pump chip are you using?
2. What is the voltage rating on your electros?
3. What are you using for power?

[Neil mcNasty]

Induction has a very good point here...
Often you will find that many wall-wart style power supplies put out higher voltages than specified, when the load is low. One of mine puts out almost 15v whitout any load (or with a small load, like below 100mA)
- So if you are using a MAX1044, that has a 9v maximum limit, and will in a case like this fry the IC. The ICL7660s handles up to 12v and is a safer option.
- Make shure you use electrolytics rated for 36v or more (allways double value compared to real voltage) since the internal power is raised to 18v via the charge pump.

I hope you figure it out!
The pedal sounds great and is allways on my pedalboard when being away from my Silvertone amps (which sounds very close to the Supro Thunderbolt amps)
Hopefully someone traces the Twin Twelve as well, in the near future...

[Ncuab]

I'm using an Texas Instrument LT1054CP IC chip.  Could it be the IC chip?  I just tried building two more Superbolts and they both have a high pitch squeal when I'm not playing anything.

At least the IC chip didn't start to smoke or one of the electrolytic caps didn't explode this time.

[induction]

2. What is the voltage rating on your electros?
3. What are you using for power?

[Ncuab]

My caps are rated at 50V and I'm using a VDL PP2+.

[induction]

In that case, I agree with Neil: build problem. Post photos and voltages, and we can probably help you sort it out.

[Ncuab]

How do I take voltage?  Here are the photos:

[induction]

Ncuab wrote

How do I take voltage?

Apply power to the circuit, and set your DMM to DC voltage. Put the black lead somewhere on the ground strip, then put the red lead on each leg of the transistors and IC. Write down each measurement and post them here.

If you bought a bad batch of 10u caps, that would explain your problem with this build and with your TS808, but that's just a guess at this point. Does your DMM measure capacitance? Pull the 10u caps one-by-one, and measure them for resistance and for capacitance. They should read as an open circuit (infinity) on the resistance setting, and somewhere near 10u on the capacitance setting.

By the way, you said you built a few, and half of them didn't work. Are the pictures from one that worked or one that smoked?

[Ncuab]

I'm hoping it's a bad bag of 10u caps.  I've built a lot of pedals, including complicated Klons, and I have over 5 Superbolts that don't work.

The pictures are from one that doesn't work.  It doesn't smoke and it doesn't work.

Here are the voltage readings:

1: 9.3
2: 5.1
3: 0.0
4: 0.0
5: 9.3
6: 1.4
7: 2.5
8: 0.1

[Ncuab]

How do measure the capacitor with this DMM?

[induction]

As you've seen in the other thread, you can't use that DMM to measure capacitance. But that's ok. If your 10u caps are bad in the way that would cause the problems you describe with this and other circuits, it would be because they are internally shorted. So measure the resistance of the caps instead. If they're good, they'll read as open circuits (infinite resistivity) on all resistance settings. (Set the DMM to the 2M range. If they're good, they read 'inf' or something similar.) If they're shorted, they'll measure some (probably very small) resistance. (Set the DMM to 200 or 2k. If they're bad, they'll give a number instead of 'inf'.)