psu ac240as-01 dell Optiplex 7010 pc tower

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

i would try swapping the chip,
but before you do, if you want to check the input it may not react how you want because of the pfc circuit.
if you leave the mosfet out then in theory you can plug it in and check the power on the cm6800 pins
and see if the standby is running

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

If I understand right, I put out the mosfet, plug the PSU in and meassure the voltage on the CM6800 and can the values compare with the working PSU?

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

On the bad PSU I put out the mosfet plug it in and compared with the good PSU I found a difference on a transformer on pin 3 (see attached picture) between good and bad PSU. The other voltages I found, where exact or nearly the same between both PSU.

Transformer bad PSU
pin 1: 312V
pin 2: 1.590 up to 1630V
pin 3: 306V

Transformer good PSU
pin1: 312V
pin2: 1.600 up to 1670V
pin3: 462V!

On IC CM6800 where no voltages measurably. But I haven't tried to switch it on via shorting pins on the ATX plug (neither the good nor the bad PSU).

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

i was going to say that you probably need to power it up to get power to the chip.
but i forgot

what your seeing on pin3 is probably caused by the pfc booster,
does the 5v standby have 5v on the bad psu?

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

I appreciate your help very much stj, thanks!

I compared now the values of CM6800 on both PSU, there are some big differences. What I should mention is, that I have connected a consumer (HDD) on the good PSU!

Pin...Bad PSU....Good PSU
01:....7,26..........0..........IEAO
02:....1,5...........1,4
03:....0..............0
04:....4,8............3,6.......VRMS
05:....9,84..........0..........SS
06:....3,95..........2,59.....VDC
07:....2,56..........2,52
08:....0,75..........0,18.....RAMP2
09:....0..............0,01
10:....0..............0
11:....5,64..........1,2.......PWM out
12:....0,06-0,1....1,3.......PFC out
13:....13,97........13,2
14:....7,59..........7,49
15:....2,53..........2,5
16:....0,46..........0,77.....VEAO

Do you think this IC is broken because of the differences?

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

does pin5 have a capacitor on it?

btw, pins 11 and 12 you need to meter the frequency, not the voltage because they will be pulsing

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

I found only a small SMD capacitor. Measuring with diode mode shows the same values on both PSU. Measuring farad seams not to work soldered in, shows 0 also on both PSU.

@pins 11 & 12: OK, but I only have a multimeter and a second one for measuring capacitors.

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

so your multimeters dont do frequency?
all mine do.

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

Unfortunately it seems to me not, only V, A, Ω and hFE.

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

"voice" ??

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

It's the name: Mc Voice M-930L

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

o.k.
well if your willing to risk a fet, try swapping the cm6800 if your sure there are no bad transistors between it and the fet.

but use a 60w lamp bulb in series with the power to limit the current.
you may stop the fet blowing like that.

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

I suppose to buy a new CM6800 and try it with this one, then I can leave the working PSU as it is.

Where should I connect the 60w lamp bulb?

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

in series with the mains supply - like a fuse.

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

The new CM6800 arrived today, I soldered it in and also connected a 60W lamp bulb in series with the power main in, also I shorted the green/black cable of the ATX connector to switch on the PSU. After connecting with main power, the lamp bulb goes on and off, also the PSU does so (fan begins to spin, slow down, spins... so did also the green led on the back side of the PSU). The fet still seems to be ok, after this test.

Is this a sign, that I may try it without the lamp bulb, or is there still something wrong?

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

remove the green/black link first and see if the 5v standby runs with the lamp still in circuit

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

I have 5V on the violett cable of the ATX connector.

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

then you can try it with a higher wattage lamp if you have one - or risk the fet a run it direct
i reccomend a bigger lamp 100w or more

[matser]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

I've tried it also with a 100W lamp, nearly the same, but I forgot to mention, that I also have connected a HDD. Without this HDD, the fan is spinning, but the green LED on the backside shows no light neither with the 60W nor the 100W lamp. Also there is a fizzing sound coming from the PSU.

[stj]

Re: psu ac240as-01 dell Optiplex 7010 pc tower

a lot of psu's dont run well without a load, thats probably the fizzing