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
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.
the LT1054 are good til 15v though... so thats why I am wondering what happened.
Quote from: LaceSensor on November 01, 2012, 01:51:55 PM
the LT1054 are good til 15v though... so thats why I am wondering what happened.
Ah. Sorry, I got them backwards. :)
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?
Zeners are finicky, there may be too much current going in to it, post the schematic.
That or you have a short.
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
I clipped the pin of socket relating to,pin1 of the ic...
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
I've got a CPA Maxx chip, ill try that, I appreciate it might whine or create a noise...
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...
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 ?
72s are ok I think, I swapped them both out and the same result.
Next will be the (expensive) diodes :(
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 :/
Quote from: Scruffie on November 03, 2012, 04:29:44 PM
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.
Ian,
Did you ever figure out what was causing this? Just had a build for a friend brought back to me with - sure enough - a blown 9v1 diode. Took the MAX1044 with it by the looks of things.
The friend claims he had it hooked up to a Voodoo Lab ISO5 9v tap.
Quote from: eldanko on February 06, 2013, 11:36:02 PM
Ian,
Did you ever figure out what was causing this? Just had a build for a friend brought back to me with - sure enough - a blown 9v1 diode. Took the MAX1044 with it by the looks of things.
The friend claims he had it hooked up to a Voodoo Lab ISO5 9v tap.
The problem with a 9.1V Zener is that it has 5% tolerance, and most power supplies -- and new batteries -- run slightly above 9v (my one-spot idles at 9.43v, which is close to a new battery). A 10v might be safer, and it's still no where near the 12v that would fry the MAX. The fact is a Zener is not a regulator and never will be. There is a little circuit called a Zener follower that would be much better and would act a LOT like a regulator without as much voltage loss, you might want to look at that if you're repairing it and have room in the enclosure.
I think your friend might be mistaken about where he plugged it in, though. Ask him if he heard a high pitched whine climbing in frequency before the pedal stopped working.
Quote from: midwayfair on February 07, 2013, 02:17:26 PM
Quote from: eldanko on February 06, 2013, 11:36:02 PM
Ian,
Did you ever figure out what was causing this? Just had a build for a friend brought back to me with - sure enough - a blown 9v1 diode. Took the MAX1044 with it by the looks of things.
The friend claims he had it hooked up to a Voodoo Lab ISO5 9v tap.
The problem with a 9.1V Zener is that it has 5% tolerance, and most power supplies -- and new batteries -- run slightly above 9v (my one-spot idles at 9.43v, which is close to a new battery). A 10v might be safer, and it's still no where near the 12v that would fry the MAX. The fact is a Zener is not a regulator and never will be. There is a little circuit called a Zener follower that would be much better and would act a LOT like a regulator without as much voltage loss, you might want to look at that if you're repairing it and have room in the enclosure.
I think your friend might be mistaken about where he plugged it in, though. Ask him if he heard a high pitched whine climbing in frequency before the pedal stopped working.
It's not an over voltage issue, the zener should be good for any voltage discrepency a '9V' supply/battery puts out.
The zeners here are burning out from over current as i've said, they're just pulling too much and shorting or opening. It needs either a current limiting resistor or the better option, to just be left out, a series 1N400X diode would be a much better solution, protecting from polarity and dropping any supply by 0.6V to keep the MAX below the 10V threshold (which Frequency Central proved several times can be gone over anyway... even if it's not good practice).