Maestro Sample/Hold problems

[Ry]

I built a Maestro Filter/Sample Hold a while ago.  I really like it, but it the Sample/Hold setting frequently latches up and either doesn't switch to a different frequency until I rotate the speed pot or it stays set on the same (either low or high) frequency while switching.

This problem has gotten worse lately.  Any ideas on how to fix it?

Thanks a lot!

Ry

[Travis]

http://www.generalguitargadgets.com/v2/diagrams/fsh1asc.gif

I encountered the same problem when I built mine.  I did two things to solve it.  

One, I tried just about every transistor I had in the noise spot (Q4).  I ended up using an MPSA13.  This might be a nice spot for one of those high leakage Ge's that everyone here accumulates.

Two, after I found a good noise tranny, I brought the 10k trim (R27) outside of the box.  I started with a 10k pot and found the useful range.  Then I put in a 1k pot with resistors on each side so that the pot had function through its entire rotation.

R27 needs very little adjustment to send the noise section back into random bipping and bopping.  With anything more than 1k, I found myself wishing for a multi-turn pot.

[Ry]

Thanks for the quick reply!  I have a nice noise transistor, but I will certainly try one of my many leaky germaniums (can't use it for much else) and then put in the trimmer.

Thanks again!

Ry