Trem Face New Build Issues

[teletroy]

I recently built a Trem Face-  using the geo schem- got he board from ggg -  When I switch it on, I get the normal guitar signal, but no trem.  I've looked over the circuit several times and it looks fine- obviously it's not  Does anyone have a voltage chart or some ideas where I should start with this thing, it's driving me crazy..

I appreciate the advice. :oops:

[R.G.]

Try this:
Measure the DC voltages of all the pins of all the active devices in there and post them here.

We can usually tell from that.

[teletroy]

Thanks for the quick response...

q1 -
g 2.37
S 6.85
D 0

q2
g 8.15
s 8.15
D6.1

q3
c Varies between  2.5 and 4.3
b 1.4
e .80

THANKS

[R.G.]

q1 -
g 2.37
S 6.85
D 0

Probably OK. I need to understand what you used for ground reference better, but this could be OK.

q2
g 8.15
s 8.15
D6.1

And here's why you have no tremolo. The gate/source voltage difference is zero, so the JFET is always on, not varying. The source should be at ground; I'm assuming you put your meter black lead on battery -, so the source is at


q3
c Varies between 2.5 and 4.3
b 1.4
e .80

[R.G.]

Sorry - I  clicked the wrong button.

q2
g 8.15
s 8.15
D6.1  

And here's why you have no tremolo. The gate/source voltage difference is zero, so the JFET is always on, not varying. The source should be at ground; I'm assuming you put your meter black lead on battery -, so the source is at battery voltage the way you're measuring. The gate should be a couple of volts negative of that, and wobbling around with Q3's collector. Check for voltage across the zener and how much of that is getting to the JFET gate. Perhaps you have an open pot, open resistor, bad solder joint, etc. on the way from the zener to the gate of q2.

q3
c Varies between 2.5 and 4.3
b 1.4
e .80

Which is about right.

[teletroy]

Thanks, I'll check that when I get home!

[teletroy]

swapped out q2 and checked the voltages and they were varying like they should.  I plugged it in and got a tick tick tick sound that changed with the knob.  I must have wired the switch wrong, I stuck a wire from the input jack to a couple of spots on the board until I got some trem sound, so I think Im almost there.

Thanks!

[teletroy]

I took the switch out and hard wired the jacks- I get guitar sound but no trem.. AHHHHHHHHHH  Back the drawing board, after I throw it against. the wall... anyone need a trem face that doens't work cheap? :|

[R.G.]

AHHHHHHHHHH Back the drawing board, after I throw it against. the wall... anyone need a trem face that doens't work cheap?

The anger is Mother Nature's way of finding out if you have the patience to learn to build your own effects.

This is why I generated the "What to do when it doesn't work" sticky. When something doesn't work, you have two paths to go: you can drop kick it into next week, or you can dig in, figure things out step by step and get it running, learning some things along the way.

The reason I generated the step by step voltage stuff is that it works. When you make a change, go back and see if the voltages changed.

So - what voltages do you have now?

[teletroy]

OK, I'm clamer now.  Deep breaths

ok here are some voltages-   I used the - on the battery for ground
q1-
g 2.3
s 6.75
d 0

q2
g varied around 5
s 8.07
d 2.4

q3
c varied around 3
b 1.27
E .76

Z1
5.44 across the zener
a 2.62
k 8.07


I also used an audio probe and attempted to follow the signal - I get sound up to the middle tab on the pot - and then the other tab there's nothing.

Thanks again, I really do appreciate it.