So out of fun I browsed for the IPP6R190P6 FETs on ali, and the most legit listing which is the cheapest looks to be this one. Only 1 bought, but store has 95.3% positive feedback.
Might be a gamble, seeing how most of the negative reviews were about fake/very poor quality parts...
Safest way would be to order from TME, but the shipping is too expensive just for 3 FETs (I don't have anything else to order at the moment).
Any thoughts on this?
kotel studios
Senior Member
Last Activity: Today, 11:14 AM
Joined: 12-09-2024
Location: Lifes edge
-
Another cause for your issue of them not wanting to power on, is that the OCP/UVP kicked in and needs to be reset. Usually it's enough to cut mains power to the PSU and wait a few seconds before powering it on again, but I suspect you have waited out at least 30 sec before you turned them on again...Leave a comment:
-
Can make an standard AM3 board POST just fine, so now it's just to order a fresh pair of correct IPP60R190E6 in TO-220, not TO-220 FP.Leave a comment:
-
Yup, that was the issue!
Now with 500mA load on 5VSB, the voltage stays near 5.10V (5.09V) and I can finally make my sacrificial board turn on!
While I could just write the verdict of this repair, but since I still don't have the correct TO-220 FETs to fully test if this PSU will handle 750W I can't.
I'll just keep the load under 100W and see if normal boards will post fine.Leave a comment:
-
Well, one side was connected to two pins of the 5vsb transformer, while the other to anode of that B2050G.
Maybe it's just another filter cap, either way it's more than out of spec which could cause the issues I had with 5VSB.
Found an used 2200uF 16v Ltec cap from a dead chieftec PSU. Seems to be inspec, so should be good enough for confirming if that's the only issue (which hopefully is the only one).Leave a comment:
-
Well, would ya look at that, bad startup cap! Was it well hidden tho, under a coil and a isolated wire.
Puffed up but not leaking. Hopefully it's the only issue (aside from ordering correct TO-220 FETs).
Rated 2200uF 16V, reads 1008uF
And as my luck would have it, no 16V 2200uF caps, only 1500 or 3300uF. Could also replace it for a poly, not sure if it makes sense to.
The B2050G diode is also fine.
And yup, I was measuring to sec. GND, not primary negative side....Last edited by kotel studios; 09-07-2025, 10:59 PM.Leave a comment:
-
Correct me if I'm wrong, but the starter cap should be in similar place to this guy in the typical application schematic, right? The one near the bridge rectifier is just to filter it. Or are we talking about the small SMD cap smoothing pin 2 to pin 1 (GND) on the PCB photo I posted?...
Last edited by kotel studios; 09-07-2025, 12:49 PM.Leave a comment:
-
Well, this is odd.....
So I've measured the pin 2 of FSB127H and... the results are questionable...
Without mainboard:
PSU with mains applied - ~4VAC
PSU ON - ~5.3VAC
With mainboard:
Mainboard OFF - ~4.7VAC
Mainboard with shorted PWR_SW (still can't power it on) - ~60VAC
Now that 60VAC is very questionable. Max this chip can handle is 30V according to the datasheet. From what I could read from the typical application schematic, it also uses DC voltage and not AC (I made sure the MM is in the correct mode, in DC mode it...Leave a comment:
-
I just got an idea to inject extra 5.10V into the 5VSB rail with the board plugged in. That was I guess we could find out if the mainboard will power on while the 5VSB rail is being "assisted" by my benchtop PSU. I would probably need to limit the benchtop to 500mA instead of 1A (this board needs ~700mA 5VSB current when off).
As for the 5VSB caps, all of the electrolytic ones around the transformer were replaced (there aren't any more on the pre-main power generation circuit). There is one small cap near the primary FETs which I haven't checked since it's in a place hard...Leave a comment:
-
I give them 5-6 minutes to cool off before measuring them (enough for them to feel room temperature).
As for the TNY chip, nope. Model is (FS)B127H by Fairchild. That's the only 8 pin IC I could find which looked responsible for the switching near the primary side.
As for the 5VSB circuit, 5.10V is when PSU has mains applied with no mainboard as load. When I give it 500mA it dives down to 4.8V.
Mainboard is a known good sacrificial one, can power it on with any of the good PSUs I own....Leave a comment:
-
Okay, that 100uF 50V cap near 5VSB transformer had been replaced. With one 330uf 25V cap (this one was fine) near the supervisor PCB (the other 220uF 25V was in spec with cap. and ESR and I didn't have any replacements on hand), alongside one 47uF 50V cap on the supervisor PCB itself (4.7uF 50V wasn't replaced for the same reason).
Sadly no improvements. These were basically all of the caps not responsible for main power rail filtering.
Main rails are okay with load that isn't an mainboard.
Any ideas?Leave a comment:
-
So after I've checked all the caps around 5VSB transformer, I found only one 1500uF 16V cap by Koshin which showed as an resistor on my LCR meter (it was reading the value fine if I pulled the cap mid-check, it also took a long while to finish).
Sadly, no major improvement. Only now 5VSB with the mainboard is at 3.7V (0.35V increase from the previous reading). FP pin stayed the same.
Still, I cannot boot up the mainboard.
The one other Ltec 100uF 50v cap checked out fine (read within +/-5% of capacitance), although my LCR didn't give me the ESR value.
...Leave a comment:
-
New day, and more weird stuff happening!
This time primary capacitor burning through an 10k 1W resistor while being charged up to 320VDC. So I took an 100k resistor to discharge it and what do you know, bright flash and voltage dropping to 75VDC! I DIDN'T EVEN ACCIDENTALLY SHORT IT!
Kotel's curse shining again with it's weird issues only I have...
Primary FETs aren't shorted yet, so hopefully nothing else got screwed (I saw thin gray strands in the air after the arc).Leave a comment:
-
I forgot to mention, with the 0.4A load without mainboard, the 5VSB dips to 4.8v :/
It'd be odd how bad caps would appear on an 2013 unit. Sure, they aren't high quality (all secondary are Ltec iirc), but like, it's too new to have bad caps.
Bad caps are very likely. Should I also check those on the vertical PSU output connector PCB (one where ATX24, GPU etc connectors are located)? Those are near impossible to check (need to somehow remove that big trace of tin).Leave a comment:
-
Okay, PSU can turn on with 0.4mA load on 5VSB.
Switching protection from 120W to 500W also doesn't change 5VSB voltage (stuck at 4.2V). Although now the board stays on and doesn't shutdown.Leave a comment:
-
I think we've found the issue!
5VSB with mainbard plugged in which is OFF dives down to 3.45V! I also hear a high pitched squealing from the PSU (probably 5VSB generation circuit). When the board is turning on by pulling FP low, it skyrockets to 4.2V. Probably limited by the light bulb protection.
Now this is weird since the PSU is fine with spinning up three 3.5" HDDs with it, but when I just plug in a mainboard and short FP suddenly the APFC has issues with the bulb protection.
My idea now is to isolate the corshair's 5VSB rail and inject 5v from my benchtop...Last edited by kotel studios; 09-04-2025, 07:58 AM.Leave a comment:
-
Okay, so the top resistor marked "205" reads 1.998MOhms, while the bottom one marked 473 reads 8.75Kohms.
All measured in circuit.Leave a comment:
-
I've shorted the FP pin to GND by using the probing wire I've soldered earlier.
Light bulb protection set to 120W max is flashing rapidly (I'm guessing this is the APFC struggling to charge?). The board after I press the power button powers on for around 3-4 seconds and then dies (if I'm slow enough it powers on it's own). It is not because I'm shorting the FP probing cable to the case and the connection is weak (I triple checked if the case is actually connected to ground and it was).
I can power up the mainboard for another 3-4 seconds by pressing the power switch on it.
...Leave a comment:
-
Here are my measurements
WITHOUT mainboard
FP pin is around 4.8v OFF
FP pin is 0.20v when PS_ON is shorted
WITH mainboard
FP pin drops to 2.35V mainboard OFF
No reaction to mainboard powerswitch.
Shorting PS_ON with GND makes FP pin dive down to 1.95V, still doesn't startup.
PG is also good, 5.08V on output when PSU is started without any mainboards....Last edited by kotel studios; 09-03-2025, 08:40 AM.Leave a comment:
-
PSU doesn't switch itself on. It was that dead asus board which did. PSU stays off until I force it to by shorting PS_ON with gnd.
Attaching supervisor board pictures. It is based on Weltrend WT7502. That solder blob on the back is factory. Don't know what corshair did.
PCB PSU model
...Code:D750E005L/D850E003L 9MC850E00FCTX5LF REV.: 03
Last edited by kotel studios; 09-02-2025, 11:29 AM.Leave a comment:
No activity results to display
Leave a comment: