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Projects => Tech Help - Projects Page => Topic started by: Mike B. on November 08, 2012, 08:03:54 PM

Title: Kingslayer - weird power cycling loop of death
Post by: Mike B. on November 08, 2012, 08:03:54 PM
Hi all,

Just wondering if any has run across this. I just finished a Kingslayer build (buffered). It works fine in bypass mode (which tells me the buffer is probably okay). When engaged, it works fine for about 10 seconds, although none of the clipping modes seem to make a difference in sound. After 10 seconds or so it goes into a weird power cycling death loop where the power cuts in and out (LED flashes on and off as well). It gets faster if I let it go on. I checked for solder bridges, etc. and all is well. I've built literally 20 or more Klons with other PCB's and have never run into this. I'm using a TC1044SCPA for regulator.

Any ideas?
Title: Re: Kingslayer - weird power cycling loop of death
Post by: Mike B. on November 08, 2012, 08:09:36 PM
Wiring -

(http://www.mikeballard.org/100_4928.JPG)

(http://www.mikeballard.org/100_4930.JPG)
Title: Re: Kingslayer - weird power cycling loop of death
Post by: jkokura on November 08, 2012, 08:12:01 PM
I would bet you've got a solder bridge in your power section. What steps have you taken for debugging thus far?

Jacob
Title: Re: Kingslayer - weird power cycling loop of death
Post by: midwayfair on November 08, 2012, 08:16:13 PM
Dead power cap or zener, maybe? Does the gain knob do anything? Pretty dangerous situation to get voltages, though, for better troubleshooting. :/
Title: Re: Kingslayer - weird power cycling loop of death
Post by: Mike B. on November 08, 2012, 08:19:15 PM
A short makes sense - probably my power supply detecting the short, shutting off, powering back on, detecting the short again, etc. I'm puzzled why it didn't happen in "bypass" mode though, because the circuit is still "powered".

I'm in the process of removing everything from the enclosure. I'm usually very careful about visually inspecting the boards for solder bridges before I box everything, but that doesn't mean there isn't something too small to catch at a glance.

Title: Re: Kingslayer - weird power cycling loop of death
Post by: Geosh on November 08, 2012, 09:42:34 PM
Check your orientation C26 (and c25). It looks like C26 is backwards. They should be opposite directions but it looks like yours are the same way.
Title: Re: Kingslayer - weird power cycling loop of death
Post by: Mike B. on November 08, 2012, 09:50:25 PM
Yup! Good catch, thanks!
Title: Re: Kingslayer - weird power cycling loop of death
Post by: Geosh on November 08, 2012, 10:08:31 PM
No prob! I did the same thing with a tantulum cap on the first Klone build I did.  ::)
Title: Re: Re: Kingslayer - weird power cycling loop of death
Post by: Om_Audio on November 08, 2012, 11:15:28 PM
Nice, glad you all got it sorted.

You know, I was going to suggest an issue with a cap possibly just based on some breadboard experimenting I did last night where I sort of saw how caps charge or discharge rather slowly sometimes. Without going into all of that, could you explain what would be happening with a reversed cap?
C

PS- don't forget to post a top shot!
Title: Re: Kingslayer - weird power cycling loop of death
Post by: oldhousescott on November 09, 2012, 01:08:29 AM
Nothing to add, since you already got it sorted, but can I just say day-um, that's some nice work!
Title: Re: Kingslayer - weird power cycling loop of death
Post by: Mike B. on November 09, 2012, 01:55:59 AM
Thanks all, working great now. And, thanks for the compliment - I'm pretty OCD about my wiring. If only I'd been as careful with my component placement :)

Oh, and Jon - I used a pair of OA126's that I got in that batch from you a few months ago. I think they are now my favorite clipping diode!