Stereo auto pan help

[tony d]

Hi guys,
I recently built the Stereo auto pan and am having some problems.
I am only getting a stable clicking on the outputs and cannot hear any of my input signal coming through.
I've traced my input signal to the correct pins on the lm3700 but on the outputs i just get a loud steady clicking.
I've checked that the lm3700 is getting voltage.The readings i'm getting on the input bias is -10.8v on each side which seems to hold steady.The output voltage i'm getting from the tl084 is around -6v and rising but i only have a digital meter so i can't really see it ever go above -4v.
I've checked voltage to all the ic's and made sure all joints looked good but other than that i'm stuck.
Any helpful suggestions would be very much appreciated.

[jordroid]

Any luck yet? I can't quite tell what is going on, you mean that you are checking the output of the TL084 with a multimeter, expecting to read the swing of the LFO? That should work, you can check at pin 1 and pin 7.

Another way to see if the LFO is wobbling might be to tack a wire to pin 1 or 7 of the TL084 and run it to the input of a correctly working module, the FM input of a VCO for instance. Since the LFO is supposed to swing from -4 to +4 it should sweep a VCO through around 8 octaves if applied to the 1 volt per octave input. If you have a friend with a scope, call 'em up!

If the LFO works, have you messed with the trimmers much? If you have the "minimum signal" trimmer set way too low it might do what you are describing.

If trimming doesn't fix it then just quadruple check everything, it kind of sounds like the LFO is biased too low or something, but it's hard to tell from here.

I'll help if i can,

regards,

jordan

[tony d]

Hey Jordan,
Sorry to waste your time i should have written this sooner.

I realized i had 3 different resistor values wrong.
Leason learned to check my values before popping them on the boards because 2 of the values were my fault but 1 was a wrong value that Mouser sent.

Thanks for chiming in though and trying to help but yes after changing those 3 resistors it's working great.Super fun module!

[tony d]

Also, i should say i was being lazy by posting here before doing any leg work so that in itself was a lesson learned as well.

Again, i apologize for wasting anybody's time.

[jordroid]

No need to apologize, troubleshooting can be frustrating and lonely, much more fun and productive with company. Plus figuring out why something doesn't work when things go wrong gives us all a better understanding of why it does work.

Glad you got it working!

jordan

[tony d]

Cool, thanks for being understanding!

Finding Ray's troubleshooting guide was a big help and made me realize even though i may not understand how every part of the circuit works there is still a lot of things i can do within my ability to get it working.