Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

[teeb]

Good evening/morning everyone!

This is my first post on this forum even though I've already spent hours reading it. It's passionating!!

Since last saturday my 5 year-old 22" screen wouldn't turn on for more than 2 seconds.
I've read multiple posts which were stating the exact same problem as mine and at the beginning I thought that one of my CCFL bulb was dead (causing the other one to shutdown automatically). Going on with my investigation, I've figured out that both CCFL bulbs were functioning correctly when plugged to one of the two pairs of connector. (each at a time, obviously)

I suspect my Mirage PI-190DTLB powerboard to only provide current to only one pair of the CCFL bulb power connector (the bottom one, on my pictures, which corresponds to the upper CCFL bulb of my monitor).
The pair of connectors on the top, "CN3" and "CN4" doesn't seem to have current going out, as they don't lid their attached CCFL bulb.

I have limited knowledge in electronics and circuitry, as the only soldering lessons I had were about 12 years ago in junior high. I can solder basic components though!

My question, to the wise and experienced community, is about what I can do or test, as I find it very odd that this board only provides current for one bulb. I've eye-checked every components on the PCB very meticulously and none of them appeared to be leaking or blown.

Thanks in advance for your input.

PS: I'm planning on getting a very cheap DMM in a few hours.

[retiredcaps]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

The pair of connectors on the top, "CN3" and "CN4" doesn't seem to have current going out, as they don't lid their attached CCFL bulb.

1) The inverter transformer secondary windings for those 2 connectors could be open. You will need a multimeter to verify.

2) 2 seconds to black is described in detail starting with posts #19 and #20 at

https://www.badcaps.net/forum/showthread.php?t=10419

3) PS. Those are excellent pics.

[sabre504]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Hi this is the same psu as used in the Phillips PHP-X19 so threads on that monitor will help you .
I have marked in reds the caps that usually need changing (even if they look good) and in blue i have marked scorched area under the transformers .

If you look on the underside (pic 2) i have ringed in blue 2 chips
MTD3055VLT4 N-Channel Power MOSFET 60V/12A, DPAK
these may be failing due to onerheating hence the scorch marks on the upper face

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Thank you guys! I'll put that on hold for the time being and make sure to keep you posted as soon as I resume my repairing

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

OK, I'm back working on this board!
So, I've tested the following components with my multimeter:
- C22 ==> 0v
- C206 ==> 11.22v
- C11, C12, C201, C211, C213, C217 ==> 15.2V
- C212, C214, C216 ==> 5V

I have very little knowledge about electronics, but does it necessarily mean that the 5-volt-measured caps are bad or could it mean that they are provided with only 5v which is caused by some other component failing at delivering the desired 15.2 volts?

[vinceroger69]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

you realy need a esr meter to check the value of the capacitors they can fail in various ways.

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

The previous measurements weren't right and I cannot edit my post anymore.
Attached to this message, you will find an excel table showing the different tensions I have measured with my multimeter.

This PCB having two "channels", I think that components are used that way:
- even-numbered capacitors are within the first "channel"
- odd-numbered capacitors are part of the second "channel"

As you can see on the table attached, C207 and C206 as well as C219 and C218 have an equivalent voltage, meanwhile C209 to C217 have a solid 15.2v, C210 to C216 are reported as 5v (0,005 volt for C208).

Does this mean that the problem in my electronic circuit lies after C206 which seems to be the last capacitor to have the same voltage as its twin (C207)???

Thanks in advance for helping me out

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

okay guys I'm lost. I've checked the schematics and the tensions described in my 2 last posts seem to be normal!
I don't know what to test now... Pretty pleaseeeee, I need some help!

[budm]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

From your statement "I suspect my Mirage PI-190DTLB powerboard to only provide current to only one pair of the CCFL bulb power connector (the bottom one, on my pictures, which corresponds to the upper CCFL bulb of my monitor).
The pair of connectors on the top, "CN3" and "CN4" doesn't seem to have current going out, as they don't lid their attached CCFL bulb."

I looked at the board layout, the two inverter transformers are driven by the same two MOSFET's on the bottom side of the board, as you indicate that only one set of transformer wil light up the lamps for seconds, so it means that the one without output will more likely to have open winding or open circuits. You need to check the continuity as suggested by retiredcaps in the #2 post. See pictures, take the measurement and tell us what you read.

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

okay i'm very angry right now. I wrote a very long message and somehow badcap server didn't respond and when I had no choice but to hit "back" my message was gone...


here is a summary of what I wrote:

Thank you budm for your message.
I've tested them and here are the results: (budm's drawing)
- transformer exit on T1 : 780 Ω
- transformer exit on T2 : OL / 1

I have tested the said transformers at their entries too:
- 0.5 Ω to each pin (which is the same as the 3 fuses resistance)

I've also tested the two corresponding MOSFETs with the diode test mode of my multimeter:
- gate(black) to source(red) : 1195 Ω (T1) & 1191 Ω (T2)
- source(black) to drain(red) : 1500 Ω (T1 & T2)
- drain(black) to source(red) : 689 Ω (T1) & 687 Ω (T2)
- source(black) to gate(red) : OL / 1 for both

These MOSFETs figures being identical, I think we can rule out a MOSFET malfunction.

Does this necessarily mean that the transformer on T2 is faulty and therefore that it should be changed?

I appreciate your help guys!

[budm]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

T2 has open winding, need a new one.

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

OK. I cannot interpret this dead transformer's name: "730-703-190DTLW-LH EEL19-AD1700", therefore I can't easily find a replacement for it. Do you have any tip? how many watts? what tension? why such a barbarian name?

[selldoor]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Very hard to come by - this one will probably do - the EEL19 is the important bit
rest is date code manufacturer info etc.

http://www.ebay.co.uk/itm/EEL-19-EBJ...item231d1786f2

Does the underside look the same pin layout

Email seller and ask.

EDIT
Before you order take the old one out and re check it - sometimes the break is at the pins and can be fixed.

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Thanks, no pin visibly damaged, I've just ordered a new inverter transfo over eChinaBay. I'm gonna have to wait 3 weeks to receive it..

[teeb]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Ok, i've just soldered in the new transformer and it still doesn't work... Only this time it's not "2 seconds to black" but "0 second to black": the CCFLs never light up :/

[budm]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Did you check the resistance reading of the new transformer to make sure the pin out are the same as the original?

[jirka.jirka.]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Hello. I do not want to create new topic, so I'll ask here. I also got into the hands of this board PI-190DTLB of monitor MAG LP917W.

I fixed the faulty capacitors and FET transistors replaced. Now, my monitor turns on for about half a second (green LED) and then completely switched off (LED off) and this is repeated over and over.

Do you know where the problem might be?

thank you

[Rtech]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Post 9,shows how to measure the Inverter transformers, and these should be in the 765Ω range.

[jirka.jirka.]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

On both windings of a transformer I measured +/- same value: 720 Ohm

[Rtech]

Re: Fujitsu-Siemens L22-1W - PI-190DTLB board (2 sec to black)

Looks like you are going to have to test the Backlights then