Task TK-940TX-DF Blowing fuse

[momaka]

Re: Task TK-940TX-DF Blowing fuse

Ok
I just removed those three components (which tested OK) and the lightbulb still glows

So you have the 5VSB MOSFET and these (four!) components removed, and the bulb still glows??

You should only see the bulb glow for a moment (up to a second or so) until the primary caps charge. After that, it should go out. If not, you have a short-circuit or low-resistance path on the primary somewhere.

I'm not sure what else to suggest to check, because there are only so many paths between the primary-side DC bus across the two caps. Namely, that is:
1) A series connection of the main transformer primary side, main PS MOSFET, and Source resistor of main PS MOSFET
2) A series connection of the 5VSB transformer primary side, 5VSB MOSFET, and Source resistor of 5VSB MOSFET.

Since you have all of the MOSFETs removed... and in addition to that, you also have the main PS snubber network removed, there really is nothing else that connects the + and - on the primary DC bus. So the bulb should not glow.

But yet, it does. This means you must be missing something here that I simply possibly cannot see from the pictures.

The only last thing I can think of: you live in a country with 230V AC mains. Is the selector switch set for 230V input?

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Ok
I just removed those three components (which tested OK) and the lightbulb still glows

[momaka]

Re: Task TK-940TX-DF Blowing fuse

With the 5VSB MOSFET removed - the bulb still glows bright and stready.
And, yeah, there was definitely a short measured across the in-circuit resistor R23.

So something is drawing power across the primary cap. Still have to determine if it's the 5VSB or a component from the main PS... So let's dig a little deeper....

I removed zener diode, ZD1, and it tests as a shorted; and the short across R23A dropped right off.
Will it be ok to replace the shorted zener with a same-looking zener from another parts PSU?

No, don't replace it. Just leave it off for now. We will determine what value it needs to be later. By the looks of it, it might be a Gate over-voltage protection for the main PS MOSFETs. So most likely it is rated for 20V or less, but we will see (might need another solder-side picture of that area to determine that.)

I wont do any more removing of components and testing (that you suggested) at this stage; as this shorted zener could be the cause of the problem.

No, the shorted Zener is probably part of the problem. But since it appears connected to the Gate drive of the main PS MOSFETs, and since the main MOSFETs are removed, then there shouldn't be a short to ground. But there must be if the bulb is glowing steadily. Thus, once again, I suggest removing the two paralleled diodes (DX10?) and the blue ceramic cap in front of the big transformer. Remove them and test them out of circuit. If they show good value, remove diode D3 (located next to resistor R7.) Diode D3 takes power from the auxiliary primary rail generated by the 5VSB transformer. If that rail is shorted to ground due to over-current, then that could be causing the 5VSB circuit to not work properly and make the bulb glow too. Thus, removing D3 will isolate the 5VSB circuit on the primary side from the main PS primary-side circuits (which is what we want - we want to see if 5VSB is working alone first.)

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Thanks for the explanation.
With the 5VSB MOSFET removed - the bulb still glows bright and stready.
And, yeah, there was definitely a short measured across the in-circuit resistor R23.
I removed zener diode, ZD1, and it tests as a shorted; and the short across R23A dropped right off.
Will it be ok to replace the shorted zener with a same-looking zener from another parts PSU?

I wont do any more removing of components and testing (that you suggested) at this stage; as this shorted zener could be the cause of the problem.

What do you reckon?

[momaka]

Re: Task TK-940TX-DF Blowing fuse

Replaced the 5VSB switching transistor K3067 (which had low resistance between D and S in both directions (i probably destroyed that as well)) with a CEF02N6A (not quite the same, but close enough?).

Yes, that CEF02N6A is actually a pretty good replacement (slightly better than the original, in fact! )

Powered it up (without the TL3842P, R22, 2 X K2746) with the 60W lightbulb replacing the fuse, and get a steady glow on the light bulb, and a reading of 56W and 0.24A (which is what it also reads with just the light bulb by itself) from my portable power plug meter.

I also confirmed, with a multimeter, that there was no short between phase and neutral or earth.

Going by these results, that sounds like either the 5VSB CEF02N6A MOSFET is getting stuck On (not driven off by the C945 BJT transistor) or there is a low resistance across the primary caps... which is unlikely, because you said you tested the MOVs across the caps and found they are not reading short-circuit / low resistance.

Next up, just to confirm where the steady glow on the bulb is coming... Try removing only the CEF02N6A MOSFET and try the incandescent bulb test again. If should light up for a second or less and then go out as the primary caps charge. If it stays lit, the problem is not the 5VSB. But if not, then we have to see why the CEP02N6A MOSFET is getting stuck On (most likely never driven off by the C945 transistor, which can be due to a number of reasons.)

[P.S. Tangential to this, but wondered why the voltage divided by the resistance (3.6A) of the lightbulb wasn't anywhere near the actual reading (0.24A)

The resistance of the light bulb varies.
As the Tungsten element inside heats up, its resistance increases. This actually also applies even to NiChome wire, as well as any conductor really.

The actualy reading of the current you got agree with the power rating of the light bulb: 0.24 Amps x 240V = 57.6 Watts (which is close to 60W... though the current accuracy measurement of your multimeter may be slightly off.)

Also tested across R23A, the small resistor that's in between the primary caps, and got a short.
One leg of it goes to -ve of primary and the other leg connects to the ferrite beads.
The resistor tests OK out of circuit.

Can you double-check your results and leave the multimeter for at least 2-3 seconds on R23A while it is in circuit to get the resistance? Do you really get a short-circuit (2-3 Ohms or whatever is the lowest your MM can measure) or 47 Ohms? Reason I ask is because I'm trying to figure if there is a possible short-circuit path from the Gates of the main PS MOSFETs to ground.

You see, R23A (1 KOhm) is connected between -Ve and the Gate of one of the main PS MOSFETs, while R12 (also 1 KOhm) is connected between -Ve and the Gate of the other MOSFET for the main PS. With both MOSFETs removed, the only possible short-circuit path is through the ferrite beads and jumper J1, then out to either R7 (47 Ohms), Zener Diode ZD1, and Diode D1. To isolate which one of these may be causing the "short-circuit", you can remove them one at a time and re-take the measurements across R23A. Please let me know what you find here.

Additionally, can you remove the two gray parallel diodes in front of the big transformer, labeled with DX10 on the PCB, along with the small blue cap next to them? These form the snubber circuit for the main PS. Please check both the diodes and the small blue cap for short-circuit as well as proper parameters (diodes should have good forward diode reading on your TT meter, and the blue cap should be a few pF in capacitance.)

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Also tested across R23A, the small resistor that's in between the primary caps, and got a short.
One leg of it goes to -ve of primary and the other leg connects to the ferrite beads.
The resistor tests OK out of circuit.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

I rechecked:
The MOVs
R17
The heatshrinked resistor
The C945 transistor, (that's next to the heat shrinked resistor)

Replaced a shorted zener ZD8 (that's next to the heatshrinked resistor), that i killed by when i turned it on with the fuse, instead of using a light bulb.
Replaced the 5VSB switching transistor K3067 (which had low resistance between D and S in both directions (i probably destroyed that as well)) with a CEF02N6A (not quite the same, but close enough?).
Powered it up (without the TL3842P, R22, 2 X K2746) with the 60W lightbulb replacing the fuse, and get a steady glow on the light bulb, and a reading of 56W and 0.24A (which is what it also reads with just the light bulb by itself) from my portable power plug meter.

I also confirmed, with a multimeter, that there was no short between phase and neutral or earth.

[P.S. Tangential to this, but wondered why the voltage divided by the resistance (3.6A) of the lightbulb wasn't anywhere near the actual reading (0.24A) - and read that heat causes the electrons to vibrate and thus impeeds their ability to flow. - in this case it's by a factor of 15. So heat, and microwaves disrupts electrons, and hence atomic state - it seems very plausable that adjustable 5G microwave radiation would very well infulence the biological absorbtion of oxygen, depending upon resonant frequencies of the oxygen molecule, the biological stuctural/chemical path of oxygen into the bloodstream and haemoglobin, and the strength of the focused(?) EMF]

[momaka]

Re: Task TK-940TX-DF Blowing fuse

-you mean the two large K2746 MOSFETs and the large pink resistor R22?

Ooops.
Yes, R22 and two K2746 MOSFETs. For some reason, I was looking at the other side of R22 board designator close to the bridge rectifier, where you can see R14, so I got confused with that.

The two K2746 MOSFETs are in parallel. Not sure why they do that, though, because in a single-transistor forward configuration, the snubber circuit is usually the limiting factor as to why they don't usually make them do much above 350 Watts. But I have seen them in a few PSU designs. A good STF design will do just fine with a single transistor, though (like HiPro and Delta do with some of their 300-350W units.)

What are those two side-by-side black diode-looking components, RX2 and R13, that are between the big transformer and the plastic that's sheilding the two primary caps? - all of the four legs of them are shorted together.
This means that two of the diagonal legs of the larger heatsink-attached K2746 transistors are shorted together.

Those are ferrite beads - essentially a wire with a ferrite core on the outside. Think of it as an inductor with very low inductance, specifically geared towards use in high-frequency circuits.

Note how they are connected to both Gate pins for the K2746 MOSFETs (and since both K2746 MOSFETs are in parallel, it's normal you get a low-resistance / short-circuit across all four pins.) The reason for these ferrite beads is to stop high-frequency voltage spikes from turning On the MOSFETs too quickly or by accident, as that can damage the Gate or the MOSFET in certain circuits.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Ok
Thanks again
The MOVs are not shorted (i didn't remove them because no short is displayed across either of them in-circut - this test result obviously will not change if they are removed)
And yep, i'll retest those other components again tomorrow, in case i've destroyed any of them by not using a current-limiting light bulb. And then power it up safely with that pink fuse R22, Q1A and Q1B, and TL3842p removed.

And for the 5VSB test, do it with the K2746 MOSFET and R14 *removed* - these components removed will essentially cut off the main PS from the PSU, so you can test just the 5VSB right now.

-you mean the two large K2746 MOSFETs and the large pink resistor R22?

What are those two side-by-side black diode-looking components, RX2 and R13, that are between the big transformer and the plastic that's sheilding the two primary caps? - all of the four legs of them are shorted together.
This means that two of the diagonal legs of the larger heatsink-attached K2746 transistors are shorted together.

[momaka]

Re: Task TK-940TX-DF Blowing fuse

[edit i posted the above before your reply]

Oops. Sorry, I guess I took too long to reply. :\

OK, i'll set up a light bulb holder on some wood with aligator clips so that i can replace the fuse with it. - Which is preferable a 60W bulb, or 100W bulb?

For 5VSB testing 40-60W bulb is usually good enough. Probably 60W, just to make sure the 5VBS has enough to start.

For testing the main PS... when we get there... eventually ... the 100W would be about good enough to test the PSU with no load or maybe a fan or two as a load.

I put it back together with the main 5VSB switching transistor, Bridge rectifier, and replaced the caps, and the fuse exploded again with a flash of light.

Hmmm..
And this was with the main PS transistor removed??

Seems odd either way, actually. I suspect something.
Looking at this picture:
https://www.badcaps.net/forum/attach...1&d=1586164479
... you see the two orange components that look like ceramic caps in heatshrink tubing (close to the bridge rectifier) - take those out and measure the resistance across them. These are MOVs, and they short-circuit when the PSU has been exposed to high surge voltages. For the fuse to blow with such violence, I suspect one or both of these may have shorted. If you measure them with your multimeter and you get very high resistance (several MOhms) or open-circuit, then they are OK. Then that means something else is shorted - either on the main PS or the 5VSB circuit.

After this second fuse blew, check all of the components mentioned above in the previous posts to make sure they are still good.

And for the 5VSB test, do it with the K2746 MOSFET and R14 *removed* - these components removed will essentially cut off the main PS from the PSU, so you can test just the 5VSB right now.

The heastshrinked resistor reads 1Ω

Sounds OK.
Means it probably wasn't the 5VSB circuit that blew the fuse, which is good news more or less.

The transistor tester with the C945 reads
BJT-NPN
hFE 279 (is this the diode readings specs for the transistor? The datasheet says hFE between 130 and 400 (no unit next to these characteristics - mV?))
Ie=6.0mA

No, hFE is the current gain of the transistor. It's a dimensionless number because it is simply a multiplier. Basically, it states how many times greater the Collector current will be with a given Base current (i.e. if the Base current is 1 mA, then the collector current will be 1 mA x hFE = 1 ma x 279 = 279 mA.) That said, hFE varies with temperature, current, and a bunch of other parameters, so it is not exactly a "solid" number. That's why the datasheet gives a range (and typically states a range of currents for which this applies.)

The fact that your TT meter picked up hFE and that it's an NPN transistor means that C945 is OK.

With multimeter on diode test i get about 0.656V for B-C and B-E and no connection between E-C regardless of orientation, so i'm picking that it's good.

Yes.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

I put it back it all back together, and the fuse blew
Removed the Pink resistor, the TL3842P chip, and the two larger Field Effect Transistors, and the fuse exploded again with a flash of light.
Anyway,
As requested:
That heatshrinked resistor reads 1Ω
The transistor tester with that C945 reads:
BJT-NPN
hFE 279 (is this the diode readings specs for the transistor? The datasheet says hFE between 130 and 400 (no unit next to these characteristics - mV?))
Ie=6.0mA
Pin1=B 2=C 3=E

With multimeter on diode test i get about 0.656V for B-C and B-E and no connection between E-C regardless of orientation, so i'm picking that it's good.

[edit i posted the above before noticing your reply]

OK, i'll set up a light bulb holder on some wood with aligator clips so that i can replace the fuse with it. - Which is preferable a 60W bulb, or 100W bulb?

[momaka]

Re: Task TK-940TX-DF Blowing fuse

Nope - but i had a feeling that one of those heat-sinked components might have to be connected, so i wasn't surprised that there was no 5VSB. It's a K0367 "Field Effect Transistor Silicon N Channel MOS"
Will it be ok to reinstall it without the heatsink for quick testing?

Yes, you can reinstall without heatsink for testing.
In fact, some cheapo PSUs don't put a heatsink on that transistor... but then it tends to run so hot it darkens the PCB. :\

So for a short-run test, it's OK. For long-run fix, it needs heatsink with thermal compound.

I'm not going to remove those parts just yet because i think that i also need to reinstall the bridge rectifier for the 5VSB to work (is that diode, in the drawing of the 5VSB circuitry, part of the bridge rectifier?).

Uhm.. YES.
Everything on the primary side is powered from the bridge rectifier. Without it, you get no voltage on the big primary caps. And without that, no 5VSB either.

I also found a 2SK2654 that appears to meet the requrement previously stated. Yes?
So should i put it all back together, replace the bulged caps, and see what happens?

Well, let's take it one step at a time.
First get the 5VSB running. Then we verify that the primary auxiliary supply is OK - this is the supply that gives power to the TL3842p chip (on Vcc pin) when PS_ON is pulled low. And only then after that, replace the primary transistor for the main PS (if the original is blown) and test the PSU. Before doing that final test, though - again, place an incandescent light bulb in series with the PSU's line input to limit current should something go bad.
The problem with relying on the fuse is that by the time enough current flows through it to blow it, other parts may blow too. With the incandescent bulb, you get a nice steady glow on the bulb, which indicates something is shorting or stuck and pulling too much current.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

I'm not going to remove those parts just yet because i think that i also need to reinstall the bridge rectifier for the 5VSB to work (is that diode, in the drawing of the 5VSB circuitry, part of the bridge rectifier?).
I also found a 2SK2654 that appears to meet the requrement previously stated. Yes?
So should i put it all back together, replace the bulged caps, and see what happens?
BTW, that pink R22 resistor measres as 0.1Ω which seems to be correct

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Thanks

...the heat-shrinked resistor next to ZD6 and R21 - Remove that one and measure it out of circuit. I think it should be low resistance value.

Will do tomorrow

Also, when you performed your 5VSB test, this was with Q8 (or is it Q6?? I can't tell from the pictures) still installed, correct

Nope - but i had a feeling that one of those heat-sinked components might have to be connected, so i wasn't surprised that there was no 5VSB. It's a K0367 "Field Effect Transistor Silicon N Channel MOS"
Will it be ok to reinstall it without the heatsink for quick testing?

In addition to that, also remove the small TO-92 transistor next to the heat-shrinked resistor...

Will do that tomorrow and post results

[momaka]

Re: Task TK-940TX-DF Blowing fuse

after the coil with the blue and white dots (is that the PI coil?)

Yup, that's a PI coil.

I removed the small Fuhjyyu 50V 22uf cap that is next to the small transformer, and it tested 22uf, and it has an ESR of 1.94 ohms, which i get the feeling is way too high, and the datasheet doesnt give a measurement for impedance.

1.94 Ohms is not terrible. Small 5x11 caps can have up to 5 Ohms ESR sometimes and still be considered "in-spec" by the datasheet.

If no mention in the datasheet, then I guess it is best to replace it.

If the ESR is bad can i use a 33uf samxon GF to replace it?

I think it *should* be OK. Going up in capacitance one notch is typically OK. Generally, 5VSB circuits are not too picky about those "critical caps" either, as long as their ESR is good and their capacitance is reasonably close to original. But just to be on the safe side... if you have 10 uF caps instead (fairly common value), you could put two of them in parallel for a total of 20 uF. That would be a lot closer to specs.

R17 tests 2M ohms

That appears to be correct.

Removed the Big white box shaped resistor and it measures 12.8kohms, which is OK because it has 7W12KohmJ written on it

Good.
Looking at the circuit again, that white ceramic resistor is probably part of the snubber circuit, so no reason it should have failed (but if failed, can cause catastrophic results, so good that we checked it.) I originally thought this was Source/Emitter resistor for the 5VSB main transistor.

One a second look, that appears to be the heat-shrinked resistor next to ZD6 and R21 (can't read its designator.) Remove that one and measure it out of circuit. I think it should be low resistance value.

Also, when you performed your 5VSB test, this was with Q8 (or is it Q6?? I can't tell from the pictures) still installed, correct. This Q8/Q6 transistor would be the one next to the R21 designator. That is the "main" 5VSB switching transistor.

In addition to that, also remove the small TO-92 transistor next to the heat-shrinked resistor I mentioned above. It's probably going to be either a C945 or 2N2222A or something similar (an NPN BJT, typically.) Get a datasheet for it and check for proper forward diode readings between Base-Emitter and Base-Collector (i.e. red multimeter probe on Base and black multimeter probe on Collector or Emitter.) And no connection / open-circuit between Emitter and Collector, regardless of probe orientation.

And there is no short to primary ground (earth?) on pin 7 of TL3842P

Ok, good. We will come back to the TL3842p circuit later then, after getting 5VSB working.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

There was two Teapo 1000uf 10v caps that were on the 5VSB rail (you can see them in my last image - one tested OK, but the other one, after the coil with the blue and white dots (is that the PI coil?), tested bad with the bung bulging out of the bottom.
I put the good one back in, after the coil, and used an LGZ before the coil.

I removed the small Fuhjyyu 50V 22uf cap that is next to the small transformer, and it tested 22uf, and it has an ESR of 1.94 ohms, which i get the feeling is way too high, and the datasheet doesnt give a measurement for impedance.
If the ESR is bad can i use a 33uf samxon GF to replace it?

R17 tests 2M ohms
Removed the Big white box shaped resistor and it measures 12.8kohms, which is OK because it has 7W12KohmJ written on it

And there is no short to primary ground (earth?) on pin 7 of TL3842P

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Cool, thanks
i've got an ESR meter
And yep, it's TL3842P.
Will do all of that in the next day or two, and then post results.

[momaka]

Re: Task TK-940TX-DF Blowing fuse

i turned it on and don't have any 5VSB voltage (i haven't changed the caps yet because the ones around the 5VSB wire aren't bloated, and i think that there should at least be some voltage present regardless).

Don't assume that. Either check the output caps with an ESR meter or at least change one of them to be more sure (typically the first cap before the PI coil matters more), along with the small "startup" cap on the primary near the 5VSB transformer.

Then, check R17 and the big white wire-wound resistor in front of the small transformer (should be a low-value resistor, probably less than 4.7 Ohms.)

R17 should be a high-value resistor, so you may need to remove it out of circuit to test it accurately (also, when testing it, it might be a good idea to use test clips or at least keep your finger off the multimeter probes, as otherwise the meter might read your body resistance instead.)

BTW there is a short on the PCB where pins 2 (VFB) and 5 (Ground) of TL384P were removed.

Hmm...
I can't find a datasheet for TL384p. Are you sure this isn't a TL3842p (or TL3843p??)
As for the short-circuit on pin 2 (VFB), don't worry about that yet. However, do check resistance between pin 7 (Vcc) and primary ground (- lead of bridge rectifier.) If it's shorted, then we may have problems.

But for now, let's ignore the TL3842p and surrounding circuitry, as that's not part of the 5VSB circuit.

**EDIT**
Here is a 2-transistor 5VSB circuit of another PSU.
https://www.badcaps.net/forum/attach...2&d=1578459617
The 5VSB circuit on your PSU may not be an exact match to the above schematic, but certain parts like the snubber circuit and small transistor driver circuitry should be in a very similar arrangement and somewhat similar values.

[socketa]

Re: Task TK-940TX-DF Blowing fuse

Thanks
So, with the three components still removed that are bolted to the heatsink, as well as the pink R22 resistor and the TL384P removed (which wasn't shorted anywhere), and with the primary caps back in, and a new fuse (got a few to spare), i turned it on and don't have any 5VSB voltage (i haven't changed the caps yet because the ones around the 5VSB wire aren't bloated, and i think that there should at least be some voltage present regardless).
BTW there is a short on the PCB where pins 2 (VFB) and 5 (Ground) of TL384P were removed.

[momaka]

Re: Task TK-940TX-DF Blowing fuse

Could the bad secondary caps (or is is the Fuhjyyu primarys?) have caused the transisor to short?

Yes.
Almost certainly it was the secondary caps that caused it. Generally, if the caps haven't completely failed, the PSU will start to develop stability issues and make the PC crash long before the caps on the secondary cause damage. But if you don't have a history of the PSU and/or how long it's sat with the bad caps, then it's not a good idea to try to power it on - even briefly. I get PSUs with bad caps regularly. The only one that I ever powered up a while back, a resistor in the 5VSB circuit started smoking and 5VSB was all over the place. Ever since then, I don't power up PSUs with bad caps. If really curious, I recap with crappy pulled (but still measuring OK) cheap caps and see if the PSU works. If yes, then I do a full recap.

Anyways... regarding the troublshooting:
Let's first see if the 5VSB circuit is working and stable. No point to try to troubleshoot the main PS if the 5VSB is not working.

To do that, first replace all output caps on the 5VSB and any small caps on the primary side of the PSU. Next, keep the TLP384P, K2746 primary MOSFET, and R22 removed from the PSU. Do install back the primary input caps, though.

After this, get a 60-100W incandescent light bulb and wire it in series with the PSU's live input wire. This will prevent the fuse from blowing up should anything else be bad or short-circuited. Now plug in the PSU with the bulb in series and see if you get 5V on the 5VSB output (typically the purple wire on ATX connector).

If not, then we will need to troubleshoot the 5VSB first.

If 5VSB is working, then check R22 for open-circuit (should be a low-resistance resistor - 0.1 Ohms, if I am reading it correctly from your pictures). If the damage was minimal, you should only need to replace the K2746 MOSFET to get the PSU running... and the output caps, of course. But if not, you may need to replace the TLP384P IC as well.

As a quick test, you may be able to replace the K2746 MOSFET with any other N-channel MOSFET that has the same or higher rated voltage and rated for at least 2-3 Amps continuous. Don't worry too much about the other paramters - at least not for performing this basic test. With the MOSFET replaced, and R22 and TLP384P IC reinstalled, the PSU should work if all else is OK. DO keep the incandescent light bulb in series with the PSU, though. If it stays lit when you plug in the PSU, then likely either the TLP384P IC or the driver circuit for the MOSFET are faulty. We will go from there if that is the case.

Only this next to the fan - it's not really "huge" - so no APFC?

Correct.
That's just an EMI/RFI common-mode inductor ("choke"). Stops RFI from leaking from the PSU back into the grid and EMI from going into the PSU and showing up as noise on the outputs.

Also, replace the primary caps ASAP. This is a Andyson unit btw, and I know for a fact that they use Fuhjyyu caps (branded "LP" which is actually the series) which are asking for trouble in Andyson units. (I have one that was killed by them)

Interesting.
I've never had issues with Fuhjyyu primary caps - at least not on the big primary ones, unless we are talking APFC (which this PSU does not have.) Then again, any non-Japanese primary caps (not just Fuhjyyu) are very prone to failing when the PSU does have APFC. In fact, APFC circuits tend to stress primary caps quite a bit more, so it's not uncommon even for Japanese brands to fail if they are undersized (particularly on voltage - they need to be rated for 420V minimum, and 450V recommended, not 400V like cheaper PSUs have... but that's a whole another discussion of why.)