Fender AB763 Style Optocoupled Tremolo Circuit Question

[Wilder Amplification]

LFO and lamp driver are two separate triodes. WHich grid did you ground? I was suggesting the LFO grid.

Just a thought, what happenes if you ground the bottom end of the LFO cathode resistor and cap right there instead of running over to the jack?

Tried grounding the cathode resistors/caps to the ground buss...no change.

Also tried changing the cathode bypass to a 100uF - No change

Dropped the value of the cathode resistor on the LFO to an 820R - No change

This is way weird. This circuit runs perfectly in a Fender amp, but not in this one unless I cilp that "antenna" jumper to the junction of the 2nd and 3rd feedback caps. As long as that antenna is there the circuit works perfectly. Would having the board elevated above the chassis have anything to do with this as opposed to having it close to the chassis like it is in Fenders? Would it be better to use ceramic disc caps as the feedback caps rather than the Sozo caps?

[Wilder Amplification]

OK I'm pretty sure I nailed it.

Apparently...(and I should've known this cause I seem to remember reading about this years ago in regards to Fender trem LFO circuits) the feedback caps in the oscillator circuit are really sensitive to how they're connected. They have to be connected together on the same turret. I had them on their own turrets with jumpers in between them. As soon as I changed the layout and directly connected them together on the same exact turret, it now self starts and sustains oscillation all the way down to the lowest speed with stock value components throughout the circuit.

The lowest speed on this circuit I measured it with the frequency meter on my Fluke 189 to be about 3.8Hz. Wondering if I shouldn't increase the value of the first cap in the loop to drop this down some, or increase the value of the range resistor on the speed pot (currently have 100K, same as Fender used).

[Wilder Amplification]

Update...since I re-oriented those caps in the feedback loop, the trem oscillator is working flawlessly. Starts everytime and sustains oscillation all the way down to 3.8Hz. Sounds damn nice on a Marshall Bluesbreaker RI...mucho bueno improvement over the stock trem. Lots of depth...as the blackface opto trem has always had.

Also, the cathode lift bypass works flawlessly as well. Oscillator starts up immediately upon hitting the footswitch and stops immediately upon hitting it again.

I didn't try the other bypass methods as this is a customer's amp and was coming down to time constraints. However, maybe I'll try that on the next build.

Another thing I noticed is that this trem does not have the familiar "ticking" sound found on a lot of Fenders with the opto trem.

Again, thanks to everyone who contributed to this thread with the help and suggestions.