Vox Repeat Percussion / Skippy Tremolo woes.

[John Lyons]

For some reason I can't get the oscillator working on the breadboard.
I'm using the 2N6027 PUT.



The amplifier section is working fine.
I get a boosted clean signal but no trem.

Voltages.
Q1 C 0v B .15v E 0v
Q2 A .75v G .87v K .12v (cathode Voltage Varies with Rate pot but no oscillation)
Q3 3.56v B.83v E.25v

I have it set up as in the schematic, no substitutions other than the PUT.
I've tried a trimmer on the 33 Ohm.
Any ideas?

[brazdj]

Hello,

I have built a few of those. Have no idea if these are proper voltages but they all work. All readings with knobs turned down, input unplugged, one spot 9.37v
Skippy build with mods by Nocontelli (sp?):
Q1 2n5089 E 0v B 0.45-0.50v C 0v
Q3 2n5457 D 5.38v S 1.32v G 0v
2N6027 A 5.92v G 5.35-5.44v K .03v

Vox Repeater:
Q1 2n5088 E 0v B 0.30-0.43v C 0v
Q3 2n5088 E 0.5v B 1.0v C 4.94v
2N2646 B2 7.42v E 3.36-4.78v B1 .04v

To ask the dumb question, did you add the extra resistor when you use the PUT instead of the UJT?

[John Lyons]

Thanks you for those voltages!
I did add the 3k9 resistor like in the
circled PUT schematic.
Looks like my Q2 voltages are WAY
off. I'll have to poke around and see
if I can find the issue.