Corsair TX650W won't start, controller IC cycles

[lordvader88]

I have this TX650W that hooked up to a PC, just keeps cycling. The 5V STBY DC-DC section seems fine. The 12V,5V,3.3V seems fine except for some spikes that might set off the over-volatge?, but IDK.

The controller chip on the secondary is PS229
https://www.techpowerup.com/articles/160/images/ps229.pdf

thing cycles through the normal start-up, FaultProtectionOutput goes low for 300ms as it runs the rails at load levels. And the voltages do look well within spec's except for some spikes on different run's I tired on a Tek2430A using its fancy capture features.

I've mapped out a lot of the schematics, but not all yet, and lot's I don't understand/new to me of how these work. The primary side is a lot more straight forward in my mind.

Basic ESR in-circuit cap test seems about right...but I'm really new to using this LCR meter. The opto's are working about what makes sense to me.

On other incredibly similar contoller ICs, they say that 5mV difference between Vsense and Isense will trigger over-current-protection and FPO will go back to high. I really don't know it thats the problem. I don't really trust my Tek2430A trying to measure 5mV between 2 channels.

I have a BM869 and a Keithly 171 microvolt DMM

But to really get a 5mV measurement, in the 300ms that it tries to run normal..........I don't see that working well either for me.


What normally causes cycling problems ?

And with regards to under/over voltages spikes, some of which would be higher/lower than the ref. voltage, how long is the time duration of them that would trip OV/UV and , Would the chip wait the full 300ms before going back to FPO high state...meaning an opto shuts off the power to the PFC/PWM chip on the primary side.