Dell E153FPB Back Light problem

[Welchs101]

Re: Dell E153FPB Back Light problem

Well, i resoldered all the tranformer pins and the pins of the transistors.

I put the new fuse in and its working fine.

Bad thing: The only fuse i had was a 3.0A Fast blow fuse. The original fuse was 2.0A. So i will probably have to order the 2.0A fuse but for now it seems to be working.

Thanks for the info retiredcaps.

[retiredcaps]

Re: Dell E153FPB Back Light problem

i remeasured that wierd reading of -128Kohm and now i get 5MegOhm. So i may have screwed up that measurement somehow.

I will solder in the new fuse and let you guys know what happens.....of course i will resolder/reflow the parts you have suggested.

-128K ohm is probably from

http://www.flukecommunity.com/forums....php?t-61.html

I fixed a Benq board that just had a blown fuse. Of course, I checked all the transistors, etc, but while waiting for the part to come in, I forgot to resolder the transformer pins. After I put in the new fuse, the monitor died 24 hours later with a blown fuse.

So I resoldered the transformer pins and put in another fuse and now it works fine.

[Welchs101]

Re: Dell E153FPB Back Light problem

i remeasured that wierd reading of -128Kohm and now i get 5MegOhm. So i may have screwed up that measurement somehow.

Anyway, thanks.

I will solder in the new fuse and let you guys know what happens.....of course i will resolder/reflow the parts you have suggested.

[Welchs101]

Re: Dell E153FPB Back Light problem

yes it was -128Kohm.........

thanks to all for the info!

[retiredcaps]

Re: Dell E153FPB Back Light problem

I used the diode check feature:

Transistor A:
Emitter(Red lead)-Base(BLack lead): 0.5V
Emitter(Red lead)-Collector(BLack lead): 0.183V

Transistor B same readings as transistor A

Transistor C:
Emitter(Red lead)-Base(BLack lead): 0.499V
Emitter(Red lead)-Collector(BLack lead): 0.182V

Transistor D same readings as transistor C

I assume the above measurements are in circuit? I measured a similar working Benq board and I get like readings on the E-C in circuit. I get 0.177V and I know my board works.

Transistor F:
Pin1(Red)-Pin2(Black): 7.68Mohm
Pin1(Red)-Pin3(Black): 25.39Kohm
Pin1(Red)-Pin2(Black): -128Kohm

Is that a negative 128K ohm reading or a typo?

Do you think if i have resoldered mosfets and transformers that this will fix the problem. Any think else i should do to help prevent fuse from blowing again in the future?

I think resoldering all the transformer pins and the c5707s and J598 should be all you need.

PS. Great clear focused picture.

[Rtech]

Re: Dell E153FPB Back Light problem

I would also check Collector to Base on the four 5706/5707's,and then the associated E and F if necessary.The fuse can fail for no particular reason(maybe age...like me),and I also resolder the transformers, the grey caps behind them and the two coils behind them.

[Welchs101]

Re: Dell E153FPB Back Light problem

A friend gave me a Dell E153Fpb monitor. It has the same problem that has already been discussed here. The Fuse (PF751) seems to have blown. I measured the transistors (see enclosed pic) and they seem ok but i wanted to get a 2nd opinion on my measurements.

I used the diode check feature:

Transistor A:
Emitter(Red lead)-Base(BLack lead): 0.5V
Emitter(Red lead)-Collector(BLack lead): 0.183V

Transistor B same readings as transistor A

Transistor C:
Emitter(Red lead)-Base(BLack lead): 0.499V
Emitter(Red lead)-Collector(BLack lead): 0.182V

Transistor D same readings as transistor C


Transistor E and F have markings of J598. Cant find it on the net. So i used resistor measurements between the 3 leads.

Transistor E:
Pin1(Red)-Pin2(Black): 7.61Mohm
Pin1(Red)-Pin3(Black): 25.37Kohm
Pin1(Red)-Pin2(Black): 0.493Kohm

Transistor F:
Pin1(Red)-Pin2(Black): 7.68Mohm
Pin1(Red)-Pin3(Black): 25.39Kohm
Pin1(Red)-Pin2(Black): -128Kohm


I also re-soldered the pins of the inverter transformer.

I have a spare 2A fast blowing fuse but i didnt want to put it into the board until i was reasonably sure the the mosfets were ok.........

Do you think if i have resoldered mosfets and transformers that this will fix the problem. Any think else i should do to help prevent fuse from blowing again in the future?

[Lazza]

Re: Dell E153FPB Back Light problem

Heres a bit of info that may help in fixing this monitor. I was asked to fix one of these today with the flashing screen and green light. Replaced two of the SC5707s put it all back together and the problem was back!!
Stripped it back down and the two transistors gone again!
Just wondering what to do next when I noticed the square grey capacitor between the two transistors was wobbling! Looked with the magnifier to find both of its joints were dry and loose. Resoldered and put in two new transistors and up she ran.
Still running so hope thats a fix but it shows there are always new answers to old problems.
Cheers
Johnboy183

The first thing i noticed when looking at the board was the grey cap loose.
BTW monitor still running after 3 days, looks like its sorted

[PlainBill]

Re: Dell E153FPB Back Light problem

Heres a bit of info that may help in fixing this monitor. I was asked to fix one of these today with the flashing screen and green light. Replaced two of the SC5707s put it all back together and the problem was back!!
Stripped it back down and the two transistors gone again!
Just wondering what to do next when I noticed the square grey capacitor between the two transistors was wobbling! Looked with the magnifier to find both of its joints were dry and loose. Resoldered and put in two new transistors and up she ran.
Still running so hope thats a fix but it shows there are always new answers to old problems.
Cheers
Johnboy183

Good job on that one. It seems like the entire production run of Dell E153FPbs are plagued with bad solder joints in the inverter. Another point to pay close attention to is the transformers. Bad solder joints on those are often responsible for shorted transistors.

PlainBill

[johnboy183]

Re: Dell E153FPB Back Light problem

Heres a bit of info that may help in fixing this monitor. I was asked to fix one of these today with the flashing screen and green light. Replaced two of the SC5707s put it all back together and the problem was back!!
Stripped it back down and the two transistors gone again!
Just wondering what to do next when I noticed the square grey capacitor between the two transistors was wobbling! Looked with the magnifier to find both of its joints were dry and loose. Resoldered and put in two new transistors and up she ran.
Still running so hope thats a fix but it shows there are always new answers to old problems.
Cheers
Johnboy183

[Lazza]

Re: Dell E153FPB Back Light problem

Hi guys, great site.

I was given the task by a work mate to find out what was wrong with his Dell E153FPB. (Good mate...I know).

The symptom was a blank screen with a flashing on/off button. (tripping)

After looking and testing all electrolytics and fuses on the board, plus resoldering loads of dry joints to no avail, I was a little stumped.
Having searched google, I came upon this site and was immediately directed to the C5706's.
Sure enough, 2 of them were dead short. Ordered 4 from ebay and took just 1 day to arrive. Slotted them in and giving the board one final inspection, I put it back together. Low and behold it works a treat.

Thanks for the information guys.

I have a little experience with monitors and tv's so i'll be glad to help out where/if I can.

I think i'll be hanging around this site for quite a while

[EGuevarae]

Re: Dell E153FPB Back Light problem

I was wondering if I can use C5707 transistors for the C5706 ones, because the one on my board are C5706

I have done it (once) and they are still working.

[PlainBill]

Re: Dell E153FPB Back Light problem

I was wondering if I can use C5707 transistors for the C5706 ones, because the one on my board are C5706

As far as I know, yes. They are a higher rated version of the C5706.

PlainBill

[kenpospeed]

Re: Dell E153FPB Back Light problem

I was wondering if I can use C5707 transistors for the C5706 ones, because the one on my board are C5706

[PlainBill]

Re: Dell E153FPB Back Light problem

I have an E153FP (about 20 of them, actually) and of the (3) I've tried to repair so far with this kit :

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220488756040

only (1) has worked. I've replaced the 6 transistors, 1 fuse and re soldered the leads on the 2 transformers.

With 2 of the monitors, they are still flashing "ON" for a sec properly working, then the back-light goes dead but the power light stays on and you can barely see the test pattern image on the display.

Is there something else I should be checking on these boards ?

Thanks !

There are a lot of possible causes for the 'Two Seconds To Black' problem. You've already seen one of them - bad transistors. Other possible causes include bad (aging or broken) CCFLs, bad wiring to the CCFLs (especially the solder joints at the ends of the tubes), open or shorted turns on a transformer, bad capacitors, and defective components in the backlight safety circuit.

Eliminating the CCFLs and wiring is easy. Take your good board and try it in all of the other monitors. Tag any that don't work as suspected bad CCFLs or wiring.

Next, try the boards from the monitors with bad CCFLs / wiring in your good monitor. Tag any that don't work as needing further testing. Now try to match up as many good monitors with good boards as you can. Save one or two working sets for comparison purposes.

Now you can get down to the real troubleshooting. Open up each monitor to the point you can check each CCFL and wiring. Measure the resistance of the secondaries of every inverter transformer. Check the 6 transistors and the fuse on each board. Replace any caps that show any signs of bulging. Any boards that are still bad are candidates either for more advanced troubleshooting or for use as parts donors.

PlainBill

[RacerX10]

Re: Dell E153FPB Back Light problem

I have an E153FP (about 20 of them, actually) and of the (3) I've tried to repair so far with this kit :

http://cgi.ebay.com/ws/eBayISAPI.dll...m=220488756040

only (1) has worked. I've replaced the 6 transistors, 1 fuse and re soldered the leads on the 2 transformers.

With 2 of the monitors, they are still flashing "ON" for a sec properly working, then the back-light goes dead but the power light stays on and you can barely see the test pattern image on the display.

Is there something else I should be checking on these boards ?

Thanks !

[PlainBill]

Re: Dell E153FPB Back Light problem

Hi new to this forum but have already found a boat load of valuable information - but I need more.

I have a Dell E173 FPB LCD Monitor which has developed a bad flicker.

I've opened it up thinking I would find some bulging capacitors but all look fine and I cannot see any area's in need of soldering.

The monitor flickers randomly and I've tried with a couple of PC's and Laptop but to no avail.

It also flickers when not connected to anything as you can see by the video that I've posted on Youtube.

http://www.youtube.com/watch?v=FzgP9t3GNZM

Anyone got any idea's?

Thanks in anticipation of some assistance

It MIGHT be the logic card; the panel electronics board (usually under a cover on the LCD panel itself) is more likely, but I would bet it's a bad connection on one of the ribbon cables between the panel electronics board and the side of the panel itself. If you can locate the point where exerting pressure makes it work better, you MIGHT be able to put something in place to keep it working.

PlainBill

[nostebbi7]

Re: Dell E153FPB Back Light problem

Hi new to this forum but have already found a boat load of valuable information - but I need more.

I have a Dell E173 FPB LCD Monitor which has developed a bad flicker.

I've opened it up thinking I would find some bulging capacitors but all look fine and I cannot see any area's in need of soldering.

The monitor flickers randomly and I've tried with a couple of PC's and Laptop but to no avail.

It also flickers when not connected to anything as you can see by the video that I've posted on Youtube.

http://www.youtube.com/watch?v=FzgP9t3GNZM

Anyone got any idea's?

Thanks in anticipation of some assistance

[PlainBill]

Re: Dell E153FPB Back Light problem

OKAY! I got the monitor to show me a picture but now the ccfl go on for like 3 seconds when i first turn it on, then it goes off again, but i can clearly see the image on the monitor, just no brightness

Good! You've at least got it to show a picture. There are several possible causes for the '2 seconds to black' problem. If you haven't resoldered all the pins on the inverter transformers, do it now.

Next, there are several versions of the power supply / inverter board in this monitor. I will need a picture of the back of yours to be able to identify test points.

PlainBill

[jschiefer]

Re: Dell E153FPB Back Light problem

OKAY! I got the monitor to show me a picture but now the ccfl go on for like 3 seconds when i first turn it on, then it goes off again, but i can clearly see the image on the monitor, just no brightness