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Low Rider IC heats up.

Started by icecycle66, September 28, 2012, 09:21:48 PM

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icecycle66

Problem:
IC 4 heats up.  It gets too hot to touch for more than a few seconds.  I'm tellin' ya, it gets really hot.  It gets hot fast, whether or not the effect is engaged.  I do not have a battery snap, I am only using a 9v plug.

None of the pots work except the octave up, it seems like it's controlling all the octaves and the clean signal but I can't really tell.  

Things I've checked:
Checked for solder bridges.
Checked orientation of IC's and caps. The IC's are socketed.


Substitutions:
R15: from 24k to 22k
R55: from 160k to 150k

Mods:
I omitted C12.  I put a little wire jumper there, should I not have done that?
I switched C10 to 1n instead of 10n.

Do you guys need me measure anything specific? I didn't want to leave the circuit plugged in since it heats up whether or not the effect is off.




midwayfair

Is it in backwards? That'll cause what you're experiencing.

Scruffie

Quote from: midwayfair on September 28, 2012, 09:53:35 PM
Is it in backwards? That'll cause what you're experiencing.
He's said he's checked it but yeah, check again.

Those substitutions should be fine.

Something is orientated wrong or bridged in there though i'd have to say.
Works at Lectric-FX

icecycle66

I took all the IC's out, then put them back in again.
Still heats up.

Om_Audio

Did you ever get this sorted? Hard to see from the photo but you might try a magnifier and examine the solder joints closely to be sure there are no bridges. I tried to get ideas as to where prob might be from the schematic but it's just a bit over my head. IC4 looks to be oriented correctly as do the trannys. Good luck!
C
Sent via soup cans and string.

dbharris

I think if you clip or desolder that jumper in C12 it should work.  See this post for reference: http://www.madbeanpedals.com/forum/index.php?topic=5622.msg48457;topicseen#msg48457

good luck!

-Dan

midwayfair

#6
Wait, you jumpered C12? I thought that was a funny looking ceramic cap. Well spotted, Dan! [Edit: I now see that it's mentioned in the first post. Doh.]

Remove that jumper. The upper octave pot is connected to the +9v source, and C12 connects to ground. You've connected your +9v through the upper octave pot (100K reisitance max) to ground.

FWIW, I troubleshot one of these for literally months and to this day can't figure out what's wrong with that board.

icecycle66

#7
Alright.

I have been messing with it by doing stuff like put a new trim pot in, and changed ICs.  i put a new IC in slot 4 and it doesn't heat up.  Everything works (2 down octavoe is very quite, but I credit that to it being so low in pitch) now except for the Oct up.

I will clip the jumper when I get home and update accordingly.


icecycle66

Cut the green wire.  That did it.

Thanks guys. 


dbharris

Really glad it is working for you!  Trouble shooting can be really frustrating.  I am trying to finish up my enclosure for a lowrider this weekend so I can box it up.  I'm really excited!!!

@Midway - I had an EA Trem once that would only act as a booster.  Took me a week of troubleshooting it like 5 hours a day to finally figure out that I had a bad SPST switch.  It always seems to be the little things.

-Dan

icecycle66

I'll be build reporting this and a mudbunny this weekend.  Featuring some Grind Custom special order boxes.