Harbinger One - Rate LED not flashing

[zgrav]

Are you getting those volt ranges when testing at the bulb?   I would think that those diodes in the circuit would cap the volts at the bulb from going that high.  And are you using the bulb for the light and not an LED?  (I mistakenly referred to an LED in my earlier post)

[Axeman]

Yeah I'm using a bulb in combination with LDR. LED for indicators on top of the pedal.
I read somewhere stating if the speed pot is faulty, it will fry transistors

[zgrav]

Does your bulb light up when the effect is on?   Or does it remain off? 

Setting your rate control at the slowest setting (fully counter-clockwise), the intensity control at mid-point, with the gain and offset trim pots set in the middle of their rotations, using your DMM, what voltage do you get at the bulb when the effect is plugged in?  Does the voltage change or is it constant?    If it changes, what is the range of the volts?  Does your reading change if you set the intensity control all the way clockwise?  If it changes, what readings are you getting then?   

[Axeman]

https://www.youtube.com/watch?v=auhPHlOekxk

https://www.youtube.com/watch?v=takED599vxs

[zgrav]

Thanks for posting the two videos.   Pondering what to suggest.

[Axeman]

I'm going to inject a signal and trace it with my scope.  I had to jump C22  to R56 because the negative part of c33 broke off,  I had fixed it prior to the video.

[zgrav]

I don't recall, have you tried swapping out the transistors in the LFO?   The transistors are reportedly working under stress when the circuit is working correctly, so maybe one of them failed while getting the other parts of the power to the transistors sorted out.

[Axeman]

Q11 and 12 are new 2n5088 and Q13 is a MPSA13.  I'm going to replace the Darlington transistors again.