electric mistress works! (build report)

[birt]

Someone gave me a old populated electric mistress PCB so i could box it up for him. now when i tested the circuit i got no sound at all. so i measured the power supply. it's slightly different than in the schematic (but all EHX stompboxes are slightly different right?) but overall it should be quite similar.
i had 24Vdc going in and nothing coming out. normally i should measure 12V at the 33uF cap but there's no voltage at all. i found no broken traces or broken component leads or bad soldering.

any ideas?

[birt]

i guess i should start by replacing the LM741

[R.G.]

OK, let's see - the power supply isn't working so you're going to start replacing the signal path stuff??

Debug the power supply first. Without that working, the rest of it has no chance.

[birt]

there is an LM741 in teh power supply. the opamp in the signal path is a 4558.
http://www.freeinfosociety.com/electronics/schematics/audio/pictures/electroharmonixelectricmistress.gif

i put in an IC socket and tried a TLO71. wich fried immediatly telling me i used a center positive power supply. this stupîd mistake cost me my very last TLO71. any other single opamps with that pinout i can search for in my electronics pile of junk?

i should have posted the schematic immediatly i know


edit: the only single opamp i think i've got left is a TLC271CP and that goes only up to 16 if i understand the datasheet correctly so i can't use that right?

[birt]

i rewired a little to use half of an LM358. now the opamp works (i get 6,5V at the inverting input) but still there is no supply to the circuit. there is a 2n4354 in the power supply wich might have fried an a diode. i can measure the diode and replace the PNP

[birt]

replaced the PNP with a bad spec ac128 i had lying around and whoppa! it works.

this is by far the most ugly effect i ever made (cosmetically that is) but sounds great

i'll post some pics soon.