Wierd power / grounding issue - GC Chimaera

[LaceSensor]

HI

Im building a chimera
When I powered it up, I got some smoke. Not sure where from. Nothing seems burned.
The Power supply I used works fine on other pedals.

When I test power even at the jack, its reading 0.36v.
When I test just the power barrel its over 9v (unregulated wall wart thing)

I have all the diodes in the board just fine, correct way round.
Think the zener may have fried... not sure?

Also im using a LT1054 charge pump, without PIN 1 soldered, is that cool?

Any Chimaera dudes, or just general dudes please chime in...

thanks

[midwayfair]

Yikes.

The Zener will work as protector and regulator to a point, but if your supply is consistently spiking over 9.6v, then it could very easily overload the zener and, consequently, fry the charge pump (which would be a candidate for releasing the magic smoke but not being as obvious about it as a blown diode). There's an easy fix to make sure it never happens again -- get out a little piece of perf or vero and hook up a 9v regulator on your supply.

I'd pull the zener and the charge pump at least and replace those; they're the only parts really likely to blow.

[LaceSensor]

the LT1054 are good til 15v though... so thats why I am wondering what happened.

[midwayfair]

the LT1054 are good til 15v though... so thats why I am wondering what happened.

Ah. Sorry, I got them backwards.

[GrindCustoms]

Holy Jebus! This is a first for me, i never tried to build one with LT1054..

But Jon idea of putting a 9Vreg is good, i would put it directly on the DC jack, so you can connect the 9V supply of the circuit directly to the output of the Vreg, no need for a L7809 (the big package one), a 78L09 will do it, i've use some in couple builts that i wanted to run certain circuits on 9V and other on 18V.

The Zener may have fried, even if it brings the surplus voltage to ground....

Just a noob checkup...are all your caps rated over 16V?

[Scruffie]

Zeners are finicky, there may be too much current going in to it, post the schematic.

That or you have a short.

[jkokura]

I'd like to know what you mean by 'pin 1 not soldered'

Even if you've installed pin one into a socket, and the socket pin is touching the solder pad, it's bad. Pin 1 of the LT1054 needs to be clipped, or bent back, or the pin from the socket needs to be removed entirely in order for it to work properly.

Jacob

[LaceSensor]

I clipped the pin of socket relating to,pin1 of the ic...

[jkokura]

So there's no chance of pin one of the IC connecting to pad 1, even by accident?

That would potentially give you the symptoms you're experiencing.

It sounds to me like the best course of action would be to swap charge pumps. If you can borrow a TC/Max1044 from another build for a second, that would at least give you verification that it is or isn't the pump. If it has the same symptoms, you know it's something else in the build.

Jacob

[LaceSensor]

I've got a CPA Maxx chip, ill try that, I appreciate it might whine or create a noise...

[LaceSensor]

Hi

Ok so I got the power back and I think the IC voltages look ok.
The controls seem to behave as expected, its just REALLY quiet.
I dont have any voltage either side of the Ge diodes Ive put in (1n34a)
Do you reckon these fried ?

I replaced the 9.1v zener diode to get it working again...

[Comfort Player]

I would pull the 34s next.  I had one die and lost all sound. Even without the diodes in the circuit you should still have full volume. I have built several of these with a diode lift setting and they still have full volume 

Are you sure your TL072s are ok ?

[LaceSensor]

72s are ok I think, I swapped them both out and the same result.
Next will be the (expensive) diodes

[LaceSensor]

So I socketed the diode positions, tried again, and the zener got really super hot again, and the pedal still doesnt work.

Im sure Its something Ive done wrong but I cant figure it out.

I have a drilled enclosure here for a Klon too :/

[Scruffie]

Zeners are finicky, there may be too much current going in to it, post the schematic.

That or you have a short.

I'm assuming it's working as a shunt regulator, if so you may need to increase the value of the resistor to it as it's pulling too much current.