Here's a weird one. I tried using 9203s and a single LED in the Naughty Fish, and in many settings on the Sweep control I got motorboating oscillation. I measured them in the dark and they're idling at 200K just like they should and with the up/down switch flipped they're idling under 10K.
VTL5C1s work fine on the same PCB with no oscillation and measure the same resistances in-circuit.
Anyone have any ideas? This is a truly weird one.
try to measure the voltage across R22 when you have motorboating to calculate the current drawn. It might be exceeding the Op Amps capacity for some reason.
Quote from: drolo on November 29, 2014, 09:52:54 AM
try to measure the voltage across R22 when you have motorboating to calculate the current drawn. It might be exceeding the Op Amps capacity for some reason.
I think if that were true the sweep control would have stopped the motorboating.
But current draw with a single LED (for both photocells) should be less than with two LEDs in series (from two photocells) regardless.
I'm just making excuses to avoid desoldering again, though.
Did you ever figure out what was going on with this issue. I'm having the same issue with the photocells
Quote from: John S on February 24, 2017, 03:06:54 PM
Did you ever figure out what was going on with this issue. I'm having the same issue with the photocells
Nope, I just used the 5c1s to stop dealing with it.
Cool. Thanks