Corsair GS800 Power Supply Problem

[R_J]

Re: Corsair GS800 Power Supply Problem

Check that the power supply is in standby when not connected to any pc. If the main power supply comes on before the ic sees a PS/ON signal the ic might not detect the voltage properly and give a false error

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

I think a valid PGI is more than 1.5V. I guess you have to trace that pin back.

[R_J]

Re: Corsair GS800 Power Supply Problem

The power supply should not come on when there is nothing connected to it, if it does then something is telling one of the optocouplers to turn on the main primary supply I don't know which one it is but I suspect it is the one (U3?) just below the J22 letters. The other opto next to it is likely for feedback for the main supply, and the other optocoupler by itself, is feedback for the standby circuit.
If the power supply is in standby there should be no +12v,+5v,+3.3v going to the WT7502
The PSONB seems high, I would think it should be around +5v or less (the datasheet says max 7v)

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Probed the IC (WT7502) that provides PG signal. Does the problem look like an IC issue or a problem elsewhere? These values are from power on state-the only state I can get from the power supply (constant on) and green to ground no connection:

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

PG is only .0873v

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Odd...Hooked to a 125watt desktop. Computer powers on instantly does not load windows and does not respond to the power button. PS acts as if it is in constant power on state. Voltages are all normal. Odd.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

very good find! keep my fingers crossed that it works after you reassembled it.

You read my mind....will install and see and of course let you know what happens.

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

awesome!

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Preliminarily it works!!!!!!!
Tremendous ty


12.2v
5.0v
3.3

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

very good find! keep my fingers crossed that it works after you reassembled it.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Good find, BUT is the power supply going to work? lets hope so.

Stop now while we are ahead...? Will post results in a few hours....

Fixed break and we now have continuity across the primary winding as originally predicted.

[R_J]

Re: Corsair GS800 Power Supply Problem

Good find, BUT is the power supply going to work? lets hope so.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

BINGO! Pin 5 (per post 33) has two wires and one is cracked/split. Looks like QC issue. The wire was not long enough during the manufacturing process and came up short it appears...so just add a glob of solder? Friday Build. I never would have found that without you guys. OH CANADA...!

[CapLeaker]

Re: Corsair GS800 Power Supply Problem

an open primary would do it alright. As RJ already said, check the thermal fuse in the primary, if it has one.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Check the primary winding to those pins that are cut off, I suspect there might be a thermal fuse in the primary. I marked where it might be, but it could also be between the other cutoff pin. check the resistance between those pins, the transformer might be fixable.
You posted a picture of the secondary side, But post a similar picture of the PRIMARY side. I might be able to tell if there is an imbeded fuse

Feedback Yellow: .78
Primary Green: 1
Thermal Fuse Red: open
Might be here Blue: 1

Primary Side:

[R_J]

Re: Corsair GS800 Power Supply Problem

Check the primary winding to those pins that are cut off, I suspect there might be a thermal fuse in the primary. I marked where it might be, but it could also be between the other cutoff pin. check the resistance between those pins, the transformer might be fixable.
You posted a picture of the secondary side, But post a similar picture of the PRIMARY side. I might be able to tell if there is an imbeded fuse

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

Solder joints look good. Primary winding is actually two wires whereas the feedback is only one wire.

Curious. If I am getting .19 on the secondary side that suggests the primary winding broke early in the wind?

Is it possible to fix this transformer? If i could find the opening a small bead of solder would be an acceptable fix? It appears the outside is glued together:

[R_J]

Re: Corsair GS800 Power Supply Problem

Have a close look at the wires that connect to the pins, sometimes it can break right where it connects to the pin.

[ShortCircuited]

Re: Corsair GS800 Power Supply Problem

When the original Q7 shorted it took the primary winding with it? Unfortunately, I don't think these transformers can be sourced reasonably cheap.

Here is the suspect as oriented from the board bottom-view:

[R_J]

Re: Corsair GS800 Power Supply Problem

Feedback winding continuity.
Primary open.
Neg side of primary winding to feedback is 11 megaohm.

That would do it. open primary