Hi guys,
I just finished a Zero Point Mini and it won't fire up. So I built myself a audio probe and found I am losing signal at R16. Which connects to (pin14) LPF2 out of the Pt2339 via C17(1n5 cap). I have a few Pt2339 I've tried with no results. My voltages are
Pt2339 TL072 1 7.9 5 8.5 TL062 1 0.0 5 8.50 Regulator 1 9.05
1 5.06 9 thru 16 are all 2.45 2 7.85 6 7.9 2 4.0 6 4.19 -4.22 - 4.27 2 0.0
2 2.45 3 0.0 7 6.44 3 8.5 7 4.26 3 5.05
3 .0.0 4 0.0 8 0 4 0 8 3.93
4 .06
5 2.64
6 2.45
7 .26
8 .65
Any help would be greatly appreciated!
Jeremy
The voltages on pins 7 and 8 of the PT2399 look wrong to me. They should be closer to the bias voltage, I think. I will check my voltages tomorrow morning to confirm.
Thanks Brian! I'll take another look at it at tonight and start probing around pins 7 and 8.
Still stumped on this. I did notice the delay was working while I was probing on certain points. But that all can get it to do.
I checked my voltages. With the modulation off pins 7 and 8 measure between .6-.7v, so I was wrong about it needing to be closer the the 2.5v bias voltage. So, it looks like pin7 is misbehaving on yours. Make sure that the "ring" switch is also off when checking voltages and audio probing.
If you have not already done so, I would remelt the joints around the delay chip. If you have a continuity checker, I would then check for continuity between C11 and pin 7, and the other side of C11 and ground. When audio probing, you should hear the non delay signal on pin8 and the delayed signal on pin7 (keep in mind they will sound very ratty and distorted on these pins). From there, you should maybe check continuity on C17 and pins 13 and 14.
thanks for your help!
I check the continuity of c11 to ground and pin7 and all is good. And C17 to pin13 is connected but pin14 is not getting continuity. I reheated everything. I'm gonna recheck the rest of my resistor values, but so far they look good.
I checked all my resistors and caps and they all look like they're in the right spots. Reheated every thing again. Still got no sound. I wonder if I have a bad cap or something? Any other suggestions would be greatly appreciated.
I can't wait to record with this bad boy!