power unit repair TEKTRONIX TDS 460A

[lihach]

During operation, there was a short circuit in the power board (119-3939-01)
At the same time, some of the elements burned, which I had already made. Help determine the value of the burned resistor P-25. Maybe someone will take a photo of the site. The gratitude is grateful.

[shakalnokturn]

I followed your topic on the Tek group too. I do not have the same model PSU, but a lot of Power Systems Inc. PSUs are very similar.
Any way you could take clearer photos, including copper side?
I think your R25 is linked on one side to the large ceramic resistor (0.22ohm?) and switching transistor emitter, other side to optocoupler and green module pin8. Can you confirm?
Check large ceramic resistor between primary ground and switching transistor emitter is not open, if it did open check for burn marks near pin8 on green module.

[lihach]

I think the green module is working. After the resistor 25 burns, the oscilloscope is fully operational before being turned off by the button. Burned R-25 and controlled zener VR-3
Need photo R-25

[lihach]

I CAN DRAW THE DIAGRAM OF THIS SITE BUT IT SHE WILL NOT SAVE ME IN THIS CASE.
THIS IS THE RESISTANCE NOT IN THE CHAINS THAT YOU DESCRIBED

[Armadillo]

https://www.eevblog.com/forum/repair/help-needed-to-identify-component-in-tds460-power-supply/msg1386184/#msg1386184

You can request from him since he had his opened up as well.

[JacquesBBB]

Yes,
I answered on my post. Its a 1.33k resistor.

[lihach]

Thank you very much. I no longer hoped that somewhere I can find such information. Because this requires disassembling the device. I am ready to answer all your questions. Why did you come to repair your power supply unit?

[andy2000]

I recently repaired a TDS460, and the power supply was full of leaking caps.  Many of them weren't obvious, but there was electrolyte underneath them.  It may be related to your failure.

[lihach]

I myself am to blame. Conducted measurements without galvanic isolation