Corsair GS800 Power Supply Problem

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

I removed U2/WT7502 and the unit was still powered on. This thing is unstoppable.

I checked another working PS and a good PGO is 5v roughly

[Per Hansson]

Re: Corsair GS800 Power Supply Problem

Yeah Photobucket ruined a lot of these repair threads. Thanks for fixing the photos.

How about you start attaching them yourself then?

[R_J]

Re: Corsair GS800 Power Supply Problem

Did you ever look at the datasheet for the WT7502? Also the WT7502 does NOT turn the power supply on and off. All it does is monitors the voltage and gives a power good signal. The reason the voltage gets droped is likey due to another resistor that connects to ground that lowers that voltage so it does'nt blow up the ic's input opamp.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

PSONB Circuit:

Something wrong inside WT7502 (U7)? No continuity between Green wire and any of the other pins on the 24 pin connector, so I don't see a short circuit externally.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Check why the PSONB is always high, check the circuit from the power supply on line, it should change when that line is open or grounded.
Also it is possible that the +5v is a bit high also, it is almost 6v (I see you changed it to 5V)
I circled a point that did not look good in the picture but it might just be because it is a picture.

Thanks...maybe I can desolder PSONB and see if it powers off?

Probably the light...I flood it with LEDs for traces and photos.

Any idea how/why the voltage drop of that cap and resistor in parallel drop by 14v?

[R_J]

Re: Corsair GS800 Power Supply Problem

Check why the PSONB is always high, check the circuit from the power supply on line, it should change when that line is open or grounded.
Also it is possible that the +5v is a bit high also, it is almost 6v (I see you changed it to 5V)
I circled a point that did not look good in the picture but it might just be because it is a picture.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

NO, The ic does'nt just rely on the pgI input pin to give a pgO, high

Dont know why the PC will not post and boot if all voltages are correct. My theory was PGO was not good at .08v causing the MB to sit there in on state-PC will not power off. PSU is still odd as it is in constant on state regardless of grounding green wire. Back to the drawing board.

WT7502:
VCC-11.5
V5-5.0
V33-3.3
PSONB-9.6
PGO-.08
PGI-1.6
FPOB 4.3

[R_J]

Re: Corsair GS800 Power Supply Problem

NO, The ic does'nt just rely on the pgI input pin to give a pgO, high

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

.08v good for PGO?

Connected to PC and it would not boot to windows...black screen despite voltages 3.3v, 5 and 12 all present.

[R_J]

Re: Corsair GS800 Power Supply Problem

pgi of 1.6v should be ok, it is above 1.2v (I did'nt see the <.> in the post# 49 picture)

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

So what voltage do you have on pin #1 ?

Pin 1 of Wt7502 is PGI and it is 1.6



What is more problematic is that if the cap just before pin 1 is bad then Pin 1 would receive 15.6 volts if corrected and the max voltage is 7 according to the spec sheet for PGI for WT7502.

Correction to post 51: 14v drop not 15v drop.

[R_J]

Re: Corsair GS800 Power Supply Problem

So what voltage do you have on pin #1 ? While you are checking, what are the voltages on all 7 pins? I believe pgi voltage is quite low but needs to be above 1.2v.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Where is the 16 volts coming from?

Main transformer that we fixed earlier in this thread...through a diode a resistor/cap (parallel).....long trace another resistor/cap (ones in image-parallel) then into the PGI pin.


One side of the transformer is 12.3 and the other is 15.6-both of which are on the secondary side of the main transformer.

Neg probe is the ground/blk wires on secondary side.

Red line (roughly):

[R_J]

Re: Corsair GS800 Power Supply Problem

Where is the 16 volts coming from?

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Put your finger on that resistor. Is it getting hot?

Didn't feel warm...checked the resistor and the cap.

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

Put your finger on that resistor. Is it getting hot?

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

The resistance is 9093ohm appears as I would expect-yes 9101, so why a 15v drop across the two? Leads back to the transformer (secondary side of course) that we originally discovered had a broken solder joint. When trying to check capacitance the meter just can't lock..keeps going back to OL then like .8uf and kinda bouncing back and forth. If the cap, how to speculate the value-size and 15v+ minimum?

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

the smd resistor marking is 9101? So it should measure 9.1 kOhms. A bad cap would read a short or some low Ohms and that is not the case.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

My motherboard went out on my main PC the same day I got to this point.* RMA mode on that. Yeah Photobucket ruined a lot of these repair threads. Thanks for fixing the photos.

WT8502: https://cdn.badcaps-static.com/pdfs/...b7fe85fcd7.pdf


Tracing PGI circuit back-not far-I think I found another issue here...:


15.6v seems high going into the the resistor and cap that are in parallel, which then drops drastically at the cap (c75) and resistor (R67)? Measures 8100ohms across the the cap and resistor. If normal my PGI signal would be 15.6v. Believe spec sheets indicates max voltage of 7v. Bad cap or resistor? Pin under PGI is gnd on Wt7502.


*Next day was a Booster Coil in a Samsung monitor.

[Per Hansson]

Re: Corsair GS800 Power Supply Problem

Great fix so far!
But please attach photos to your posts.
I have attached the previous ones.
It is a great shame when a thread like this comes up empty without photos because the image-host has closed doors!