Heartthrob Trem - Depth pot not working

[solarplexus]

hi there,

my new build heartthrob trem is too choppy.  The signal goes in fine, but the depth pot is not doing anything.  I rechecked the solders, they look fine.  Check the readings on the pot, fine too.  Before doing a build, I always check every part with my multimeter to make sure every part is at the supposed value.  No sub.

Any ideas what could cause this? 

[theundeadelvis]

Be sure to read this and post your findings: http://www.diystompboxes.com/smfforum/index.php?topic=29816.0http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

Reading this and posting your voltages and such will make it much easier (and quicker) for someone to help you with the debug. Good luck!

[solarplexus]

Battery : 9.32V

Q1:
E - 0.003V
B - fluctuating
C - 0V

Q2:
E - 2.8V
B - 2.1V
C - 1.5V

Q3 :
E - 9V
B - 1.2V
C  - 0.665V

Q4:
E - fluctuating
B - 0.665V
C - 0V

I would believe Q1 would be the problem?
Having read another post of a problem with this circuit, my readings of the Q's seems to be right...  what am I missing...?

[theundeadelvis]

Can you post a schematic (or link to one)?

[solarplexus]

http://www.mrdwab.com/john/temp/Schaller-Hearthob-conversion.jpg

And this is the layout:

http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=1491&g2_serialNumber=2

[theundeadelvis]

This is a shot in the dark, but if the depth isn't working but signal is passing through, then it might not be sending enough of the signal to ground at the depth pot. Double check that 15K resistor to ground and all of those traces and solder joints.

[solarplexus]

I have looked at the traces and the soldering, everything looks fine.  I'll check it with the audio probe tonight.

thanks.

[solarplexus]

FIXED!  Problem: Q1.  Checked with the audioprobe and Q1 was the problem.  Guess that when the DMM readings seem fine it doesn't mean the parts are fine.

thanks for those who helped (theundeadelvis)

[theundeadelvis]

Glad you got it sorted out! That audio probe has saved me on numerous occasions!