Onkyo-593 No power and now clicking sound

[madan1]

Check again d901 in diode mode for short (I do not remember by heart the internal schematics of the bridge rectifiers, so I test each pin to each other pins, then switch the probes and again).
You can use IPA to find the hot component(s) - drop IPA on the component and see how fast evaporates.
Thermal print labels also can be used - cover area with a label and see where it will get black.

This power rail doesn't have too many common points to ground - q502, d516, q501, q434+q436... all other possible paths include too many components that have to be shorted. So try injecting voltage again and check that components if they are getting hot.

[Sisko]

Check again d901 in diode mode for short (I do not remember by heart the internal schematics of the bridge rectifiers, so I test each pin to each other pins, then switch the probes and again).
You can use IPA to find the hot component(s) - drop IPA on the component and see how fast evaporates.
Thermal print labels also can be used - cover area with a label and see where it will get black.

This power rail doesn't have too many common points to ground - q502, d516, q501, q434+q436... all other possible paths include too many components that have to be shorted. So try injecting voltage again and check that components if they are getting hot.

Hi there.

Ok I checked d901 in diode mode and no shorts I even took the time to take it out and recheck it just to make sure and it's OK. So while the d901 was out I decided to do another
voltage injection just in case and again no hot spot any where.

Ok decided to recheck q901 if it was working and it is faulty will not give 12v output under a 14.5v on my bench power supply, I get 0vdc on the output. So will need to reorder one again. Again no more short on c902 when q901 isn't there.

THANKS!!!

[madan1]

If the short is gone, you can try powering up the unit (without q502 and q901). Preferably through a dim-bulb tester, but even without, looks like the smps ic has a working protection and a test should not do more harm.
A good result would be stable power rails (stable voltage on c905, c902 c901 c911 c912).. from the schematics and the smps documentation, looks like the smps IC supports low and high power modes, so not really sure what should be the voltage.