Echobase Delay problem. help?

[GuitarTek86]

I recently finished an echobase delay using a beautiful premade PCB from MusicPCB.com (awesome!). Everything works as it should except it will not generate lfo. the LED pulsates to the speed and depth, but no vibrato. the LFO depth knobs is acting as an additional delay time knob. the normal time knob still works as well... any ideas where I should start to troubleshoot this guy? Thanks!

[slacker]

Ok, so the LFO is working because the    LED is flashing, and the PNP transistor is working because turning the depth pot affects the delay time. The problem is some where between the two, check the connections on the 240k resistor, the 10uF cap and the depth pot. Also, check for anything that might be shorting those connections to ground, 9 or 5 volts.

[GuitarTek86]

I am returning to this project after shelfing it for some time. the reason the lfo was not passing across the 240k resistor was because there was none (facepalm). I soldered in the 240k, and no I have no lfo, and the LED no longer pulsates.... so I disconnected the 240k resistor, and now my LED will not pulsate at all..... strange. any ideas?

[GuitarTek86]

I am returning to this project after some time. Still having the same problem. I replaced the BC560 and nothing changed. Anyone have any ideas?

[slacker]

Is your LED pulsing now or not? Voltages on all pins of the LFO opamp, the one top right on the PCB and all lugs of the Mod depth pot would be useful.

[GuitarTek86]

the LED is not pulsating at all now....

TL072:
1-4.75
2-4.75
3-4.82
4-0.474
5-3.65
6-4.81
7-1.774
8-5.59

Depth Pot:
1-0.000
2-0.261
3-0.258

BC560:
1-0.287
2-0.268
3-0.001

[GuitarTek86]

P2399:

1-4.94
2-2.48
3-0.001
4-0.001
5-2.78
6-2.48
7-0.678
8-0.702
9-2.48
10-2.48
11-2.48
12-2.48
13-2.48
14-2.48
15-2.48
16-2.48

I also tried another PT2399 in the socket. something seems fishy with the right row of pins.....??

Thanks so much for your help!

[slacker]

TL072:
7-1.774
8-5.59

Something is wrong here, assuming your supply is 9 Volts, pin8 should be about 8 Volts. If you used a socket remove the opamp and then measure the voltage on pin 8 you should get about 9 Volts, if you do try replacing the opamp in case it is damaged.

Your PT2399 voltages are correct.

[GuitarTek86]

Up and running! Swapped the TL072 with no change. turns out my battery was too low for the LFO. I was running about 7v. plugged it into my pedalboard with 9v, and it was good. Should have thought of that sooner. Thanks for all the help. Telling me the voltage seemed low is what did it. a fun pedal! I really like it!