Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

[zonaotaco]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

buenas tardes mi nombre es marcos soy de venezuela... y estoy en este foro para ver si me pueden ayudar con un problema q tengo con mi monitor especificamente la fuente de poder modelo DARFON B092-XXX Quiere camiarlos con condensadorles y los retire para los estravie y quiera saber quien me puede ayudar con decir los voltales y uf q cada uno de ellos se los agradeceria....

[budm]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

You should make a couple of test lamps to help you narrow down the problem so you will not waste lots of time trying to fix the board if the board is not bad like this example here:
https://www.badcaps.net/forum/showth...t=33720&page=3

[timg11]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

After looking at previous posts, the inverter IC is BIT3715, and the FET driver is P2804ND5G. The text on the parts was somewhat unreadable on my board, but based on previous posts, I'm pretty sure they are the same.

Next step is to test the transformer windings, but I'll have to get back to it in a few days.

[budm]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

Check the high voltage windings of the inverter transformers as suggested, DARFON is known for having bad inverter transformers, I replaced many of them.

[timg11]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

My board is identical to the photos in the first post <https://www.badcaps.net/forum/showpost.php?p=120538&postcount=1>.

[Davi.p]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

that P/N for ic is maybe a fucking chinese unknown part... i don't find nothing..

[selldoor]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

Pictures of your boards would help but you need to read posts 4/5 and test the
resistance on the secondary windings of the inverter transformers.

[timg11]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

I did some investigating with the oscilloscope, and found that the power supply to the inverter (around 24-28 VDC) looked really bad when the inverter tried to start up:

(Note - probe type is not recognized by scope - multiply voltages by 10)
There shouldn't be that type of waveform on a power supply, so after considering the name of this forum, I inspected the capacitors (these were 220uF 35V - effectively in parallel because the inductor shown on the silkscreen was replaced with a jumper). They were a bit swollen, so I replaced them.

The originals were CapXon - I replaced them with Nichicon.

After that the DC going into the inverter was clean and the whining noise was gone, but the backlight still doesn't work.

Probing on the high side of the drive transistor going to the inverter transformer (collector? drain? ... don't know - I have not been able to find a schematic for the Darfon supply), I see a waveform run for a couple seconds and stop. This repeats 3 times, then stops and a yellow LED comes on in the switch panel.
Waveform at inverter drive (20uS/Div)

Waveform at inverter drive (50mS/Div)

So there is still something wrong that is shutting down the inverter after 3 tries starting up.

The inverter IC/Transistor (5 pin DPAK on back of board) is labeled:
NIKOS P2804ND56
U145J009B

The other IC in the inverter area (SOP package) is labeled B113715 FC27G P0810

[Davi.p]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

One possible cause is ballast blue caps, is there a way to test lamps by disabling the protection, you must write here the marking on the inverter IC.

[selldoor]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

See budms signature files above - you can make a test bulb from a cfl.
First test is usually the secondary resistance on the inverter transformer?
If they are ok then it is on to bulbs and wiring.

[timg11]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

I have this exact same monitor with the same inverter that just went bad.

It started making a whining noise one day and the screen got very dim, then went out completely. When powering up now, I get the squeal from the inverter for a few seconds, then it shuts down.

It's been a good monitor and I hate to trash it, so I'm having a look to see if there is any practical fix. I've taken it apart and have the inverter board accessible. The oscilloscope shows approx 24V DC and a flyback waveform (momentarily) on the primary of the CFL transformer. The high side secondaries are covered in glue and I haven't tried to probe them yet. The text on the topside of the board says those outputs are about 1KV.

I don't have spare CFL tubes to swap out. Is there any way to measure the signal at the bottom end of the CFL tube (across the sense resistor) and determine if the problem is the tube or the inverter?

I have gathered that I can't just unplug 3 of the 4 tubes and test them individually since there is an open-tube protection circuit.

[jeffescortlx]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

@jeff: You mean that the wire to the lamp is bad or lamp is worn out with blackened ends?

It has a bad CCFL lamp, that will not light at all. The inverter goes into shut down once it knows it will not come on (over voltage on transformer secondary).

I did find parts relativity cheap. But I've always wanted to do my own DIY LED conversion. So I think I'm going to use this as an opportunity to do just that.

[budm]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

@jeff: You mean that the wire to the lamp is bad or lamp is worn out with blackened ends?

[jeffescortlx]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

The pinout for the MP1008ES is on page 9.

Thanks for the help.

Turns out it has a open lamp.

Panel model is M190PW01.

Any way to trick the inverter circuit to ignor the bad one? It's not really worth buying a new panel for it.

[jetadm123]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

The pinout for the MP1008ES is on page 9.

[jeffescortlx]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

I also have a X193w with the same problem, back light will only light for a few seconds.
But it looks like I have a different powersupply/inverter board then you other guys. P/N is E59670 ILPI-031.
The inverter is controlled by a 16pin SMD chip number MP1008ES. I cant find the data sheet for it. And would like to know what pin's are the enable/shut down.

The 5v and 12v supply runs like a champ (checked with scope). Just the darn inverter keep's trippen.

I get about 500ohms on the secondarys and .6 ohms on the primarys for both of the transformers.

[lcdm]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

hey PlainBill, in your https://www.badcaps.net/forum/showpo...2&postcount=33 post you are saying "There are a few steps that we can take to TEMPORARILY bypass the protection so troubleshooting is easier.". Is there a way to make backlight always on regardless the video signal presence or lamp voltages/currents?

[HexInverter]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

have you managed to resolve it? I am having the same problem with mine Acer x193w and Darfon B092-XXX. Unfortunately no bulged capacitors or burned elements, lamps go off after 1 or 2 sec

That sounds exactly like my problem, and no - I still haven't resolved it

It's sitting in my room waiting to be fixed still :3

[lcdm]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

have you managed to resolve it? I am having the same problem with mine Acer x193w and Darfon B092-XXX. Unfortunately no bulged capacitors or burned elements, lamps go off after 1 or 2 sec

[HexInverter]

Re: Acer x193w with Darfon B092-XXX inverter - assistance needed! [lotsa pics!]

Alright!

Sorry for the age long reply...life kinda got in the way...it probably will again, but I must see to it that this puzzle is solved eventually!

I got some time today to revisit the ring test, as per the updated instructions. I had to isolate the signal with a capacitor as said, and BLAMO! - I got ringing to display! Unfortunately the transformer exhibits a very nice (and identical) ring on both secondaries...so no easy fix! Shucks!

So, any idea of what to try next?

PS: Thanks for getting me this far! I've learned so much already!