Kompromat only works in bypass

[jimilee]

The yellow is probably just flux, you can clean that off with a little isopropyl alcohol. You're either not getting power through that diode or there is a ground somewhere after the cathode. Do you have continuity between the cathode and any ground point? You can see how the power runs from the cathode to Q5, CY, pin 7 of the IC2, C20 and so on. Clean around those areas and look for any shorts. A magnifier helps.


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[notanelectricalengineer]

I just tested the diode and I'm getting 0.18V through the diode in the right direction and nothing in the other direction. There isn't any continuity between any of the mentioned points and ground. Only the grounded points on the PCB have connection with ground, which is as expected. Still unable to find any shorts in the circuit.

[jimilee]

I just tested the diode and I'm getting 0.18V through the diode in the right direction and nothing in the other direction. There isn't any continuity between any of the mentioned points and ground. Only the grounded points on the PCB have connection with ground, which is as expected. Still unable to find any shorts in the circuit.

Wait, you don't have continuity along your power traces? Can you see any traces there?


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[notanelectricalengineer]

I have continuity along my power traces, but not between any point on the power traces and ground.

[jimilee]

I have continuity along my power traces, but not between any point on the power traces and ground.

Ohhhhh, ok. And D3 is a 5817? I can't figure out why you don't have power past the input, essentially.  I've reached out to rain, he will chime in later.


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[notanelectricalengineer]

Yeah its a 1N5817. I appreciate the help!

[Zerro]

Simply find power supply source, measure what is going from it. Connect it to your device and measure this power supply at jack to device. If power is shut down after connecting it to jack, you have some hard shortage at very start of power rail, maybe protecting diode, especially, if polarity at your power supply is (was) reversed. Power must go to pcb to opapms and so on. If protecting diode at very start of power rail is damaged, it can do this shortage.

[notanelectricalengineer]

Its a 9V power supply coming in, and I'm getting 9V on the anode of D3, but the cathode of D3 reads ~60mV. I tested D3 using a multimeter and it seems to work, but maybe its restricting too much voltage from going on to the rest of the circuit.

[jimilee]

Simply find power supply source, measure what is going from it. Connect it to your device and measure this power supply at jack to device. If power is shut down after connecting it to jack, you have some hard shortage at very start of power rail, maybe protecting diode, especially, if polarity at your power supply is (was) reversed. Power must go to pcb to opapms and so on. If protecting diode at very start of power rail is damaged, it can do this shortage.

You do make a good point. Using a wrong polarity power supply will shut it right down.

[notanelectricalengineer]

The power supply I'm using is positive on the outside and ground on the inside. I use it to power a looper I have and it works fine.

[notanelectricalengineer]

I read 9V when measuring the power supply, but when I plug it into the jack, the power coming from the jack is -9V, would this be the issue?

[jimilee]

I read 9V when measuring the power supply, but when I plug it into the jack, the power coming from the jack is -9V, would this be the issue?

Nope, that's where you want it to be. I'm curious about that diode, but I don't want o suggest removing it just yet.


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[Zerro]

Maybe shortage is after this diode shooting down all. But this D3 is suspiscious. If polarity of your power is ok, try to bridge for a moment this D3. And again measure power at rail.

[jimilee]

Maybe shortage is after this diode shooting down all. But this D3 is suspiscious. If polarity of your power is ok, try to bridge for a moment this D3. And again measure power at rail.

See, that's what I was thinking, but there's no continuity between power and ground.


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[Zerro]

Let's give him time to make some trials and measurements and then we all will be smarter.