Zalman ZM600-HP blowing PFC's

[Khron]

Re: Zalman ZM600-HP blowing PFC's

Got the 5-pack of new PFC diodes today (15A vs 8-10A for the originals - simply 'cause they were cheaper than the original-rated ones)

First-step test: removed the 10ohm resistor between the CM6800 daughterboard, and the bases of the totem-pole transistors. Plugged in the PSU through a bulb-tester - normal single flash, 5Vsb came up fine. Shorted green to ground - all the voltages came up fine too, bulb not lit at all.

I'm still a bit thrown off by the 50Hz square wave i can see on the scope, even with both probes hooked up to the SAME point With both channels at 5V/div, it's two divisions tall, so 10V..?

Scope Ch2 on the negative of the main cap and Ch1 on the "input" pad of the removed resistor shows exactly the same waveform as can be seen in the 2nd and 3rd picture (out of the 5) attached a few posts ago.

Coincidence or not, i just noticed that the "valleys" of that switching signal seem to coincide with the tops of that "ground square-wave" i get, with both probes in the same point...

[Khron]

Re: Zalman ZM600-HP blowing PFC's

Due to the fact that i'm pretty much out of ideas at this point, i'm starting to consider replacing the PWM chip - maybe the PFC section's somehow shot, but the rest isn't?

I've found some ML4800 on ebay.co.uk for ~16eu / 21$ delivered. Should i go for'em?

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

With that price, I'd rather wire in the big coil for passive PFC and be stuck with that.

[Khron]

Re: Zalman ZM600-HP blowing PFC's

Ah, sorry, slight omission above - those prices are for 2 (two) pieces

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

Still, with all the effort and parts you'll give in, you are on price for new one. If you don't have use for the second chip, than it is the same as if you'd buy one, isn't it?

[Khron]

Re: Zalman ZM600-HP blowing PFC's

Well, actually, i might have use for a second chip Apart from this Zalman, i have two other FSP Everest 1010w which are nearly identical as structure and layout, one of which has 5Vsb but nothing else (yet).

[ipo3nk]

Re: Zalman ZM600-HP blowing PFC's

maybe you should check the smd transistor under the pfc mosfet. (that drive the pfc mosfet) sometimes this small parts fail and make small value resistor (2ohm - 5 ohm smd resistor) that connected to mos pfc's gate burnt & open.

[Khron]

Re: Zalman ZM600-HP blowing PFC's

maybe you should check the smd transistor under the pfc mosfet. (that drive the pfc mosfet) sometimes this small parts fail and make small value resistor (2ohm - 5 ohm smd resistor) that connected to mos pfc's gate burnt & open.

Even the NPN/PNP totem-pole pair driving the PFC FETs checks out fine. The primary cap (OST SPS 390u/420v) shows ~349uF on my Tenma multimeter, which is in spec, and it's not bloated.

I desoldered both of them and tested them out-of-circuit, and they're both fine, so it's not that.

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

Hi,

Sorry for hijacking old thread, but I have a similar problem.

Zalman ZM600-HP (So FSP Epsilon I guess). Had blown the house breaker and so far I've found that the PSU fuse is also blown and one of the PFC fets (ref.des. Q12) seems to be shorted.

Haven't yet desoldered the PFC heatsink and components, but so far it seems that the PFC coil doesn't have any visible damage. But what I have understood, that there may be shorted windings which is not visible if the coil is not dismantled.

What have you done with these? As in what is the inductance/other specifications of the coil and where have you find replacement? Or have you guys used the same core and wound new coil on it?

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

I usually have couple similar coils lying around…

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

OK, now desoldered the PFC heatsink and the coil.

What sparse info I have gathered, everything points out that this model should have 20N60C3 PFC FET:s, but in my case it seems to have IPP60R125CP fets.

I don't have a ring tester or inductance/Q-value meter - but possibly access to one. Does anyone have any idea what kind of values to expect, and possibly where to find replacement coil?

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

Seems these Infineons can handle even slightly higher current.

Remind me in an hour or so, I'll have a look at some coils…however, the problem may be with the voltage - when using very low voltage such as these measurement instruments use, it may seem to be OK. But applying 400 V, the insulation may break down creating shorts between the turns of the winding.

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

Seems these Infineons can handle even slightly higher current.

Remind me in an hour or so, I'll have a look at some coils…however, the problem may be with the voltage - when using very low voltage such as these measurement instruments use, it may seem to be OK. But applying 400 V, the insulation may break down creating shorts between the turns of the winding.

"This is a reminder" :P

But bad news altogether, there wasn't a suitable meter in my workplace (which I have access to).

And I was afraid of just that - that one shorted turn won't swing the Q-value/inductance that much that I could detect it without knowing the orginal values...

Stripping the FETs and the PFC booster diode would make the PFC coil act as a "passive PFC" limiting the current spikes (disabling the PFC-circuitry alltogether), am I correct? But in this case, it wouldn't make much sense, if the coil is suspected to be bad. Wouldn't the switching FETs then be "in the line of fire" then?

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

Eh, not there right now…

Well in that case also remove that PFC coil and replace it with ordinary big passive one to at get at least a little bit better PF/less harmonics. I suppose you have 230V net in there?

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

Eh, not there right now…

Well in that case also remove that PFC coil and replace it with ordinary big passive one to at get at least a little bit better PF/less harmonics. I suppose you have 230V net in there?

Yep, 230VAC - I think if I would have 115VAC, I would need to boost the voltage to APFC output...

I don't understand what you mean by "ordinary big passive" coil - to my eyes this APFC coil looks just like one Enameled copper wire wound around toroidal core.

I think I have few scrapped PSU:s lying around, I'll check those for parts, but I suspect that they don't have any PFC at all... or if they have, the coils can't handle the power. Though I'm not planning to rip the power out of the Zalman either - outputting 200-300W would be easily adequate.

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

One of those big&heavy cubes from old units, it's called "passive" PFC. This thing has almost none inductance for low-frequency input (50Hz), it is intended for about 60kHz operation.

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

One of those big&heavy cubes from old units, it's called "passive" PFC. This thing has almost none inductance for low-frequency input (50Hz), it is intended for about 60kHz operation.

Ah, now I understand what you mean. Usually mounted with screws on the PSU case itself, because of the bulkiness.

Well, I did found one from the "scrap" -pile (though this one was connected before the rectifier - on the AC side - lower current through the coil when on AC side, right?).

Did connect it (and a new fuse and jumped the booster diode) -> Well at least I have +5VSB. Old CD-ROM drive was used as a "dummy load" and it kind of tries to start (when power on wire jumped to ground). I got the blue lights lit for a second and the fan spins about one turn.

DMM shows the +12V line rise to 2-4 volts and then back to 0V. Old motherboard didn't seem to have any effect either - LEDs on the mobo do light up (+5VSB is present), but PSU doesn't power up. Though I'm not sure the motherboard is working either.

Have to inspect some more, but so far thank you for all your input and expertise on the matter.

[Behemot]

Re: Zalman ZM600-HP blowing PFC's

2 scenarios possible:

- the PFC controller is combined with primary switching controller, in such case you'd have to emulate sometign on its sense pin(s) otherwise it will not start (it thinks there is problem in PFC and shuts down completely)
- you have independent controller so it should work, in that case there may be other problem elsewhere

But I do not have any pracital experience removing active PFC (booster), this is only theory of operation so maybe wait for ppl who do here…

[Mastus]

Re: Zalman ZM600-HP blowing PFC's

2 scenarios possible:

- the PFC controller is combined with primary switching controller, in such case you'd have to emulate sometign on its sense pin(s) otherwise it will not start (it thinks there is problem in PFC and shuts down completely)
- you have independent controller so it should work, in that case there may be other problem elsewhere

But I do not have any pracital experience removing active PFC (booster), this is only theory of operation so maybe wait for ppl who do here…

And the first option is the winner. CM6800G is indeed combined PFC/PWM -controller...
Have to inspect the circuit carefully, if there is a way the bypass the PFC part.

[Alekov_31]

Blown Zalman ZM600-HP

Hi,
My Zalman ZM600-HP died. the PFC is blown. I have measured all components and replaced them except R10 which is totaly blown and I cannot read the color code to replace it. I was looking for schematic but unsuccessfully. I was wondering can someone tell me the value or measure it. Тhanks in advance