Sharkfin: Sample / Hold side

[schweltzer]

Hi Guys,

built the shark fin - set it up in my test rig; the filter side works fine, but the sample hold side does not
The LED does not flash
the trim pots appear to change the "range" or frequency of the signal, but nothing is "effected" otherewise.
the LED flickers when I touch the steel of the SPD pot...
does anyone have voltages for the IC I can check?
Which path do i need to trace for the sample hold side?

[mcasemo]

I'm not good at this, but I've made a few of these (still troubleshooting one).  Check to see if you have +9v on pin 7 and -9v on pin 4 of IC4 and IC5.  At the same time check for +9 on Q6 drain and Q4 emitter.  and -9v on Q4 collector.

the sample hold side is Q4, IC4, Q5, IC5...

Do you have multi turn trimmers?  or single turn?  It can be strange to find the working spot, but following madbean instructions should get you there if it's working.