Corsair GS800 Power Supply Problem

[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

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

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?

[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.

[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.

[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?

[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

[R_J]

Re: Corsair GS800 Power Supply Problem

Thats because the WT7502 has nothing to do with turning the power supply on and off. Altjough it might for protection. There are a pair of optocouplers side by side, one will be for the primary regulation, and the other is likely for turning the power supply on and off. I believe the optocoupler for power on/off is the one below the printing J22

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

It has three optos. One of the two optos closest to the main transformer is making a weird buzzing noise that elevates significantly when checking voltage on the secondary side of the opto. The adjacent opto does is not affected by a voltage check and does not buzz. I changed the one closest to the transformer and the buzzing is the same with the new opto. I also desoldered the two terminals (secondary side) to this buzzing opto and it was still on.

EDIT: Briefly desoldered both OCs closest to the main transformer (secondary side only) and it is still running.

[R_J]

Re: Corsair GS800 Power Supply Problem

The one optocoupler by itself is likely for feedback regulation for the standby 5v. The other two, the closest one to the transformer is for regulation for the main +12,+5 etc. The one next to it, should be for turning the power supply on and off. The fault might not be with the optocoupler but could be either on the secondary side, not controlling the opto, or on the primary side, not switching the primary on and off.

You do not want to disconnect the feedback optocouplers, without the feedback (and regulation) the power supply could cause the secondary voltages to very high and cause damage.

When you open or ground the power ON pin, the voltage on the (on/off) optocoupler (led side) should change.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

No change in voltage when the on/off wire is grounded vs. ungrounded on the secondary (diode) side of the OC. OC closest to the main transformer is 10.7/11.8 and the adjacent (under J22) is 4.6/5.0v grounded and ungrounded. When I briefly desoldered all 4 pins of those two OCs that should have cut the LED signal to the primary side and turned PS off? If i can cut the on signal on secondary side and it powers off I could better isolate the problem.

[R_J]

Re: Corsair GS800 Power Supply Problem

If you remove the feedback by removing the optocouplers you risk BLOWING UP THE POWER SUPPLY!
The voltage on one of the pins of PC1 should change when the power supply is switched on and off (by grounding the wire) I will guess that either pin 1 or pin 2 of pc1 is connected to 5 volts and the other pin will be controlled by a transistor, and when that other pin is taken low, the optocoupler led will light.
So trace back pins 1&2 of PC1 and see what they are connected to, I can't make out the traces in that area from the picture.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

U3:
PC1-Pin 1 trace:...220ohm resistor (straight down on board)...purple wire (+5vsb voltage)
PC1-Pin 2 trace:.......FPOB; WT7502 Pin 3

U5:
PC2-Pin 1 trace:750 ohm SM...2200ohm SMD*...U6 (Adjustable Regulator TO-92) (UTC TL431K PCR)
PC2-Pin 2 trace: U6 regulator (pin3-10.7v)

Voltage

PC1: Grounded/Ungrounded:
Pin 1: 5.067/5.067
Pin 2: 5.6/5.6


PC2: Grounded/Ungrounded
Pin 1: 11.7/11.7
Pin 2: 10.7/10.7



*Circuit branches off here into the sunset.

[R_J]

Re: Corsair GS800 Power Supply Problem

I could'nt make out the designations from the picture so I made my own. So U3 must control the power supply on/off, but it looks like it is controlled by the wt7502 if it only connects to it's pin3.
If you still have the wt7502 removed, if you ground the pin3 trace does the power supply turn off?

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

I could'nt make out the designations from the picture so I made my own. So U3 must control the power supply on/off, but it looks like it is controlled by the wt7502 if it only connects to it's pin3.
If you still have the wt7502 removed, if you ground the pin3 trace does the power supply turn off?

I reinstalled already.

[R_J]

Re: Corsair GS800 Power Supply Problem

I reinstalled already.

You could unsolder pin3 or remove what looks like a jumper wire from pin 3 that connects to theat trace back to the opto.
Did you ever replace the wt7502?

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

I ordered some Wt7502s a few weeks ago....will be a few more weeks though.

I pulled a leg on the jumper to 7502 then grounded the trace to the OC (U3/PC1) and it did not power off (green ungrounded).

There is certainly an odd sound coming from U5 opto. when you touch the probe to it either terminal on the secondary side it makes a significant buzzing noise

[R_J]

Re: Corsair GS800 Power Supply Problem

just ground out the jumper going to pin2 of the opto, that will turn ON the internal led (the 220Ω) on pin1 is the current limiter from the +5v for the opto.
At some point the wt7502 does control this line.
The way I think it worksis:
When first pluged in, the main power supply turns on for a second and outputs the +12v, +5v & +3.3v, IF they are correct, then PGI goes high and FPOB goes low turning off the main supply, When PSONB goes low, FPOB goes high turning ON the main power supply again. Or I could be wrong.

[R_J]

Re: Corsair GS800 Power Supply Problem

I ordered some Wt7502s a few weeks ago....will be a few more weeks though.

I pulled a leg on the jumper to 7502 then grounded the trace to the OC (U3/PC1) and it did not power off (green ungrounded).

Well something turns it on and off, and that's the only way I can see it being controlled, so there might also be a problem on the primary side as well. U3 seems to connect to (Q2?) which then connects to the primary control module, This is not a simple power supply.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Well something turns it on and off, and that's the only way I can see it being controlled, so there might also be a problem on the primary side as well. U3 seems to connect to (Q2?) which then connects to the primary control module, This is not a simple power supply.

On the primary side OC U3/PC1 traces to that 10-pin riser board ( 5th pin from the right which contains a CM6800, which I did replace. maybe I could desolder this and see if it powers off?