Acer X193W Monitor (Power Dead)

[8ternity]

Hi Eveyone,

I had these monitor that is completly dead. No power on at all.

I had change 4 capacitors, tested 2 transformers, ok.

Still no power on this board.

I've try to read something on the white box; #CX101 on the primary voltage section. How can we test that part? It seem to be an transformers or something like this.

It's writen 250V/AC 0.4uf, KN81560;

What can i do more to get this board working?

Thanks.

[budm]

Re: Acer X193W Monitor (Power Dead)

Those replacement caps look like regular general purpose caps. That Grey cap is for AC noise filter, it does not have to there for the power supply to operate.
What DC voltage are you getting at that big filter cap in the primary side, measure the voltage right at the two legs?
Do you also get any DC voltage on any of those caps that were replaced?
Did you replace the small start up cap, the one next to the word 'CAUTION'?
How about that small white fuse in the cold side of the circuit?

[8ternity]

Re: Acer X193W Monitor (Power Dead)

Those replacement caps look like regular general purpose caps. That Grey cap is for AC noise filter, it does not have to there for the power supply to operate.
What DC voltage are you getting at that big filter cap in the primary side, measure the voltage right at the two legs?
Do you also get any DC voltage on any of those caps that were replaced?
Did you replace the small start up cap, the one next to the word 'CAUTION'?
How about that small white fuse in the cold side of the circuit?

Question: Did you ask me to read live current?
Reply: No i've not change the small capacitor. I can unsoldered and test it with capacitance tester to see. The fuse is conductive. i had testing it with the audio signal audible on the tester. Did you had another way to test it?

[budm]

Re: Acer X193W Monitor (Power Dead)

Yes, this is an always on power supply, it will run the minute you plug it into the AC outlet.
That cap in in the Hot side (deadly side) of the circuit, do not not touch ANY THING on the board with your hand. The voltage on that cap should be around 160~170VDC.

[lexwalker]

Re: Acer X193W Monitor (Power Dead)

I had these monitor that is completly dead. No power on at all.

I had change 4 capacitors, tested 2 transformers, ok.

Still no power on this board.

I've try to read something on the white box; #CX101 on the primary voltage section. How can we test that part? It seem to be an transformers or something like this.

It's writen 250V/AC 0.4uf, KN81560;

What can i do more to get this board working?

OMG! Are those axial leaded capacitors?! Supposed to be radial leaded capacitors. Also, recommend using low impedance/ESR type capacitors as this power supply board uses SMPS topology.

That "white box" is actually a "X" capacitor for power line noise filtering function. First, have you check the voltages across the outputs on the secondary side whether they are present and correct?

Even without bulging, that big main 120uF 400V capacitor can be bad. The only way to tell is to remove it from the board and check it using either a multimeter (charging test) or capacitance meter. Always discharge the capacitor before checking.

Question: Did you ask me to read live current?
Reply: No i've not change the small capacitor. I can unsoldered and test it with capacitance tester to see. The fuse is conductive. i had testing it with the audio signal audible on the tester. Did you had another way to test it?

Yes, check the voltage across the big main capacitor on the primary. If the fuse did not blow then its unlikely for that "X" capacitor to be source of any problems. But first and foremost, get proper low ESR capacitors...

[ben7]

Re: Acer X193W Monitor (Power Dead)

Yes, check the voltage across the big main capacitor on the primary. If the fuse did not blow then its unlikely for that "X" capacitor to be source of any problems. But first and foremost, get proper low ESR capacitors...

"X" capacitors are safety certified that they won't short out and/or catch fire.

There were problems with some of the first X capacitors, made by Rifa, in the 1980's.

[lexwalker]

Re: Acer X193W Monitor (Power Dead)

"X" capacitors are safety certified that they won't short out and/or catch fire.

There were problems with some of the first X capacitors, made by Rifa, in the 1980's.

Sometimes these X capacitors would fail, but not by becoming short. Failures such as having much reduced capacitance, became open and/or higher ESR. Not easy to detect, until desoldered them off the board to check...

[Behemot]

Re: Acer X193W Monitor (Power Dead)

Sometimes these X capacitors would fail, but not by becoming short. Failures such as having much reduced capacitance, became open and/or higher ESR. Not easy to detect, until desoldered them off the board to check...

But as long as they are not part of functional circuits here rather than just input filtration, even if it was dead or having too low capacity, that would not matter.

8ternity: have you tried only the power board itself, or always with the other things (signal board, CCFLs) attached?

[budm]

Re: Acer X193W Monitor (Power Dead)

So far we do not find out if he is even getting the proper DC on the main filter cap, I hope he did not disappear.

[konecma]

Re: Acer X193W Monitor (Power Dead)

Hello,
i have 2x acer x193w
1st time no power, after recaps one working fine, second have problem on pic 100_0437.JPG
Bud i cannot find problem. From bouth board i'm geting similar data
Can you help me?

[Behemot]

Re: Acer X193W Monitor (Power Dead)

If both CCFLs show same behaviour at two independend boards, most likely what? Most likely the CCFLs itself are bad

[konecma]

Re: Acer X193W Monitor (Power Dead)

CCFL are OK, this power board is bad

[selldoor]

Re: Acer X193W Monitor (Power Dead)

I think we need some more information on the problem.

Do you now have one monitor that works fully when connected to a pc?

Do they both have the same boards?

Are the lamps only partly lit?

Do they stay on for three minutes when lit?

Are the lamps the original ones out of the monitor?

Can you post a picture showing all the lamp and the wiring to the board.

[Behemot]

Re: Acer X193W Monitor (Power Dead)

OK, I got the information, it seems one half of the invertor on one board does not work. Other board is OK, CCFLs work OK in it. Transformer has been swapped, no change.

I'd personaly focus on the transistors but that would be some strange inter-state as usually transistor is either good or blown (which would trigger protection).

[selldoor]

Re: Acer X193W Monitor (Power Dead)

Can we have pic of back of the board?

If the connectors are changed around does the other end of the lamp light?

Are there 4 lamps or 2 with connectors at each end?

I have occasionally seen those high voltage blue caps fail so am wondering if
he can pin it down to one secondary he could try moving the blue caps and see if the problem moves with them

[budm]

Re: Acer X193W Monitor (Power Dead)

Since this only has one inverter transformer with two high voltage winding, if the primary drive circuit is bad, it will affect all the lamps not just one set of lamp, so yes, do check the ballast cap out off the circuit to see if it has any leakage resistance reading using the highest Ohm scale, it should not show any resistance at all if it is good.

[Behemot]

Re: Acer X193W Monitor (Power Dead)

Man, the world is small. I have been actually asked by this very person for a tip where to buy those high-voltage caps in the same capacity ratings…so the question is, were they meant for this display and has that been tried already?

[budm]

Re: Acer X193W Monitor (Power Dead)

I use TDK, XXpF 2K, 3KV.
I.E.:
http://www.mouser.com/ProductDetail/...vtndABaA%3d%3d

[Behemot]

Re: Acer X193W Monitor (Power Dead)

It's true that 2 kV should be enough, there is around 650 V in there.

[budm]

Re: Acer X193W Monitor (Power Dead)

There are 4 ballast blue caps (2kV min since the start-up voltage is between 1500~1800V), and also two X/Y blue caps on that board also.