Help with Hearthrob Tremolo anyone?

Started by dumbmonkey, February 26, 2009, 01:33:23 PM

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dumbmonkey

I recently built a Hearthrob using a board made by John Lyons that pretty much follows Mark M's layout.  Here's the link to that:
http://www.aronnelson.com/gallery/main.php/v/MarkMs-Gallery/album15/album76/Hearthrob_Tremolo_LAYOUT.gif.html
In any case, I have sound through the circuit but no tremolo.  I followed that parts list and used 2n5089's for the transistors.
I've checked everything for continuity and that all seems right and checked voltages on the electrolytic caps and I seem to be getting more voltage on the positive side so that seems good too.  Here are some transistor voltages measured with a 1 spot measuring 9.47 volts.

Q1
E:  0
B:  .31
C:  0

Q2
E:  1.61
B:  2.07
C:  2.82

Q3
E:  0
B:  .67
C:  9.46

Q4
E:  0
B:  0
C:  9.41

Can anyone help?

John Lyons

Sorry for the delay...
Here's what I get off my Mark m hearthob.

Q1
C 0v
B fluctuates
E 0v

Q2
C 2.9v
B 2.2v
E 1.6v

Q3
C 9.6v
B 1.2v
E .6v

Q4
C flutuates
B .6v
E 0v

Looks like we are pretty close but you should have some oscillation on Q4 Collector and Q1 base.
There is some deviation at Q3 and 4 so check for the correct resistor values and for solder bridges
around those two areas.

john




Basic Audio Pedals
www.basicaudio.net/

dumbmonkey

John, thanks!  I'll check that as soon as possible.  By the way, nice board!


dumbmonkey

FYI I found the problem, I had a solder bridge between the emitter and base of Q4.  Houston, we have tremolo.  John, thanks for all your help!