Adding DeProfundis mod board to Bow Echo delay

[FootSolder]

Interesting, with or without power the time pot lugs measure zero and that doesn't change as it's rotated, which can't be right

I'm wondering if I should undo the change suggested earlier, where the 330R on the modulation board was removed and the Depth 1 lug moved from the board to ground. Before that change I was at least getting a clear delay (so the TIME pot was working then) and a strong modulation when the LDR was connected. That seemed to be closer to getting both effects working together.

[ElectricDruid]

If the Depth pot is connected to the LED side of the vactrol, it *can't* affect the Time pot when there's no power. When the power's on, ok, the LED lights/doesn't, changes the LDR, changes the Time pot value. With no power, that's impossible. The other name for vactrols is "optoisolators" for a reason.

If the Time pot is showing zero no matter it's position when the power's off, we need to find out why. That can't be right, as you say.

[duck_arse]

Interesting, with or without power the time pot lugs measure zero

as we always say, never never NEVER with power. ON for voltages, OFF for resistances, always.

[PRR]

Extra eyes often helps.

[FootSolder]

Man, this is not getting any less mystifying. I disconnected everything from the TIME pot and it measured correctly through the range. Then I just started randomly connecting stuff.

Connecting one side of the LDR to pin 6 of the delay PT2399 and the other to ground yielded a lovely, thick modulation, with the TIME pot disconnected.

I could not resurrect the delay with any combination of lug wiring, even changed the 2399. I will go through the board again tomorrow and see if anything is shorting.

[FootSolder]

Just to conclude, I ended up connecting TIME pot lug 1 to both the delay board and mod board (one side of LDR) TIME 1, connected TIME pot 2/3 to the delay board only, then added a switch to connect SW2 (other side of LDR) to ground. Not quite what I was hoping to achieve, but one switch setting provides full delay, the other a shorter delay with the modulation circuit. I have no idea why the delay time is compromised by adding the mod circuit, would be interested to know!