Does D9 go open or short? Check TH1.
The only thing Im able to suspect is the relay. It's doing a tough job which has possibly caused the contacts to erode causing a lot of contact bounce.
BTW, you have not included your country in your profile.
I have a small PSU I've just looked at using a TOP247 I think, it is not doing anything and I suspect the TOP device.
Interestingly, the R49 snubber resistor in mine is open circuit, so you might want to check yours.
Don't know if this might have killed the TOP device or vice versa.
The only thing Im able to suspect is the relay. It's doing a tough job which has possibly caused the contacts to erode causing a lot of contact bounce.
BTW, you have not included your country in your profile.
If it was the relay, why does it do that spark sound the first time it clicks, and not every time its clicks, as I mentioned it only does that sound the first time after connecting the power cord, every other relay click after that is normal.
The country is Egypt, I don't know why that's relevant .
The bridge is ok, all diodes are measuring fine. Please remember the unit is working fine
The only thing Im able to suspect is the relay. It's doing a tough job which has possibly caused the contacts to erode causing a lot of contact bounce.
BTW, you have not included your country in your profile.
If it was the relay, why does it do that spark sound the first time it clicks, and not every time its clicks, as I mentioned it only does that sound the first time after connecting the power cord, every other relay click after that is normal.
The country is Egypt, I don't know why that's relevant .
The bridge is ok, all diodes are measuring fine. Please remember the unit is working fineIm thinking that it's to do with whether the capacitors are charged or not, maybe. Knowing your country allows us the figure out the main voltage there. Can you easily remove the relay's cover?
The purpose of D9 is to prevent C61 discharging into the 470uF capacitors when the relay first turns on. This would be audible and bad for the relay also.
Is D9 shorted at the moment?
https://en.wikipedia.org/wiki/Copper_pour
https://en.wikipedia.org/wiki/Copper_pour
I see, thank you.
Where exactly do you think there might be problems? I can add an extra layer of uv curable solder mask at these areas.
The purpose of D9 is to prevent C61 discharging into the 470uF capacitors when the relay first turns on. This would be audible and bad for the relay also.
Is D9 shorted at the moment?
The purpose of D9 is to prevent C61 discharging into the 470uF capacitors when the relay first turns on. This would be audible and bad for the relay also.
Is D9 shorted at the moment?
The positive terminal of C61 was somehow connected to the linear regulators/diode heatsink, which was in turn connected to the output of the 70V diodes through L11 and two 10N capacitors (3rd schematic top right). Removing that connection removed the issue, now it clicks normally the first time.
Thank you for pointing me to the function of D9 and the possibility of C61 being discharged into the 470uF capacitors.
The purpose of D9 is to prevent C61 discharging into the 470uF capacitors when the relay first turns on. This would be audible and bad for the relay also.
Is D9 shorted at the moment?
The positive terminal of C61 was somehow connected to the linear regulators/diode heatsink, which was in turn connected to the output of the 70V diodes through L11 and two 10N capacitors (3rd schematic top right). Removing that connection removed the issue, now it clicks normally the first time.
Thank you for pointing me to the function of D9 and the possibility of C61 being discharged into the 470uF capacitors.I would like to make better sense of that, actually sounds potentially dangerous.
Can you describe the connection? Does it seem intentional?
The top pour in the AUX supply appears to be connected to the cathode of D9, explaining it being live with HVDC.
Off-line power supplies are designed in a way that minimizes the chances of live side circuitry contacting circuitry on the isolated output side, making it dangerously live.
Having everything sharing the same heatsink structure is not safe design practice.
Im not sure what else to say at this stage except to ask, is there a mains earth connection to the isolated output side?
How is signal sent to the box? optical I hope.
I removed that connection by isolating the pad to the heat sink, I don't know what's it doing and I wouldn't risk it leaking anywhere with that dangerous common heat sink.
What are your thoughts as to it's purpose?
All the other 3 boards in this units are isolated with silicone pads, so I don't think it's used to move voltage some place else through the heat sink.