Proview PL926Wbi - recapped, same shut off issue

[Wyld_Goose]

Re: Proview PL926Wbi - recapped, same shut off issue

Caps are all in the correct polarity. I was very anal about this seeings how it was my first repair job. Drew up a diagram for myself and everything. But just to check because you asked............. yup totally confirmed.

What happens is exactly what the 2 second to black describes. Click pwr button. blue LED comes on. Screen comes on, then 2-3 seconds later it goes black. No clicks or any sounds. No smells either (I have honestly expected some kind of smell all along) The blue LED stays lit. Hold a flashlight up to it and you can see the screen is on, just not lit up.

I have found a couple threads dealing with this board, and they all seem to end up dealing with the CCFL. Again, I haven't cracked into the actual screen yet to look at the CCFLs. If anyone knows of a good video or step by step, so I can see how to do it right. I don't want to screw something up or touch something or detach something I shouldn't.

**oh and from what I can see on the thing that you think is a switching transistor, what I can see when I look real close is lowercase "t"04 on it. I can't tell if there is or was something after the "4". teenyweeny

[selldoor]

Re: Proview PL926Wbi - recapped, same shut off issue

It doesnt have an inverter board as such- the inverter transformers are the two big gray
rectangular components in Pic2.
Please can you check all the caps are in the correct way round.
Voltage looks low at the main cap.
Can you go through what happens from switch on to final fault stage what doe the power light do does the screen flash at all any ticking screeching noises.


EDIT
That "resistor" is at Q1 and I think it is a switching transistor - I will try and find it T04 you say?

EDIT2

I think it might be one of these
http://pdf1.alldatasheet.com/datashe...BZX84-A11.html

t= made in malaysia 04

[Wyld_Goose]

Re: Proview PL926Wbi - recapped, same shut off issue

The 1st pic is what I believe to be the logic board.
The 2nd pic is a pic of the 200-000-170DTLBMH power board. All caps, except the 100uF 400v, have been replaced.
The 3rd pic is of the reverse side of the power board. Took quite a few pics to get clear identifiers of the points.

OK, so what is the inverter board?

Here are all of the measure voltage readings from all caps, +5, BLON & +14 pins and the HV CCFL outputs:

C11 220uF 25v Measured @ 14.69v
C12 220uF 25v Measured @ 14.69v
*** C22 10uF 50v Measured @ 0.0v !!
C201 100uF 400v Measured @ 159.7v
C206 22uF 50v Measured @ 12.42v
C211 680uF 25v Measured @ 14.69v
C212 680uF 25v Measured @ 5.03v
C213 680uF 25v Measured @ 14.69v
C214 680uF 25v Measured @ 5.03v
C215 470uF 25v Measured @ 14.69v
C216 470uF 25v Measured @ 5.03v
C217 220uF 25v Measured @ 14.69v

CON203 pins=
BLON Measured @ 0.0v
+5 Measured @ 5.03v
+14 Measured @ 14.69v

All 4 High Voltage connectors to the CCFL Measure @ 0.0V

The 4th and 5th pic is of the reverse side of power board zoomed in at a concern with C22 ("C22" can't be seen printed on this side of the board). First of these two pics (4th) is from same angle as the 3rd pic, the 5th pic is of same location, just a different angle. The C22 cap gets a 0 voltage reading. I was concerned originally with the solder as the pics show, when I originally solder wicked away the original solder, what was left behind was the metal exposed on the board as you can see. There is a concern with the resister in the 4th pic just above the "104" resister. I can barely make out a "t04" on it (I'm assuming that it's a resister). The corner closest to the C22 looks chipped.

I haven't looked at the CCFLs yet. I'm trying to find a good video showing someone breaking into the screen. I don't want to start just tearing into it without know what not to touch and such. So far, the best I have found are low resolution videos getting into a laptop screen. (why tear something apart never knowing about that "hidden screw", when you could get a heads-up seeing someone else do it first)

[retiredcaps]

Re: Proview PL926Wbi - recapped, same shut off issue

What is the inverter board?

Post a clear focused picture of all your boards using the manage attachment function and we can tell you.

[Wyld_Goose]

Re: Proview PL926Wbi - recapped, same shut off issue

I will probably upgrade all of the caps, but for the time being to solve the issue, what I have should be fine. Just not for anything beyond getting this back on it's feet. I will get some pics posted here soon. Leave it to me to have searched for postings but missed the sticky "A guide on how to troubleshoot 2 seconds to black" at the top of this thread. doh!

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

Could I get some clarification on something said there?

Since you are seeing the image, but with no backlight, we will assume for now that the power board and logic board are working 100%. That leaves the inverter board to check.

I know of 2 boards in the case, but am unsure of the 3rd. The power board is literally the board that is plugged into from the wall socket, I assume the logic board is the one with the chip(s) on it that sits next, above or under the power board. What is the inverter board?


Actually I see how impossible it is to ask about anything, without pics. I will have them on tomorrow. I was going to ask how I am able to "to see if the main cap is getting ~165V DC" with a multimeter, but that may require pins that you need to see pics of. =/

[Pentium4]

Re: Proview PL926Wbi - recapped, same shut off issue

You should check to see if the main cap is getting ~165V DC. Also...Lelon aren't a good brand at all, I wouldn't use them even for the less critical caps, you should replace the rest with Panasonic FM/FC. Could you post some clear pictures of the board using the attach function?

[Wyld_Goose]

I am new to trying to fix a monitor. I have a Proview PL926Wbi that decided to die on me a few weeks ago. I would turn it on and it would turn off but the blue LED light on the power button would stay on. When I would lower the brightness down very low, it would stay on for a while with a little flickering and then turn off. From everything I had read up on, this sounded like a clear case of bad caps. I opened the case and examined the PSU to find no caps that had burst. The caps were a mix of HEC and Procon brands. I could see, what looked like it could be leakage, on the board around 2 of the 220uF caps and when I compared those 2 caps with another 220uF cap in a different location on the board, they clearly were very discolored and dark. I only have a multimeter, so can only check for shorts. Again with everything I had read, better to just go ahead and replace all of the caps. I hadn't discovered digikey at the time and put in an order for all but 4 of the caps from Mouser. (Mouser didn't have the 680uF 25v caps) Not to long after that, I had read up on the big-thumbs-up for Panasonic FM and bought 4 of the 680uF 25v of that model. So this is list of caps that I replaced with:

4x 680uF 25v Panasonic FM
2x 470uF 25v Lelon Low ESR from Mouser
3x 220uF 25v Lelon Low ESR from Mouser
1x 22uF 50v Lelon Low ESR from Mouser
1x 10uF 50v Lelon Low ESR from Mouser

I put the monitor back together and hook her up and she seems to work. After about 10 minutes it start to flicker, so I drop the brightness down and it stabilizes for another 10 minutes and now we are back to shutting off after a few seconds. Aarrgg! I've been doing some reading of threads on the same monitor and it seems that the AS1117 regulator was an issue on some of them. I have to admit, I really don't want to have to remove and replace something that small. With those threads where the regulator was the issue, the monitors didn't come on at all, so I'm not entirely sure if that would be my issue seeings how my monitor does come on. What I'm curious about is with the big 100uF 400v cap that is on the PSU that everyone says not to worry about. On this board it's a HEC brand, on another monitor I'm waiting on parts for, it's the dreaded Fuhjyyu brand.

What are my options at this time? It still seems like it's a cap issue.