Dell E193FPp problem

[paul123]

Hi

I have a Dell E193FPp monitor, switch it on and the desktop appears for around 3 seconds, switch it off, then on again, and the desktop appears for around 1 second... and so on.

The inverter board caps ( capxon ) show no sign of bulging or leaking.

Any suggestion most welcome

Thanks

[Bobdee]

Re: Dell E193FPp problem

Hi

I have a Dell E193FPp monitor, switch it on and the desktop appears for around 3 seconds, switch it off, then on again, and the desktop appears for around 1 second... and so on.

The inverter board caps ( capxon ) show no sign of bulging or leaking.

Any suggestion most welcome

Thanks

Hello Paul
Can you post Pics of board as there is no info on this Monitor on Forum,
It will help members to help you

[paul123]

Re: Dell E193FPp problem

I found an image of the board at the following link

http://img241.*************/img241/6...fpp423x306.jpg

[EGuevarae]

Re: Dell E193FPp problem

I found an image of the board at the following link

http://img241.*************/img241/6...fpp423x306.jpg

No use. Too small. Post a bigger one.

[Bobdee]

Re: Dell E193FPp problem

I found an image of the board at the following link

http://img241.*************/img241/6...fpp423x306.jpg

Not only too small, but you will need a picture of the back of board as well, as it seems that your mosfets etc are on there
Also when you loose image of your desktop put a bright torch to the black screen in a darkened room to see if image is still there
Some caps can look good but still be bad due to them drying out (more so the inverter caps for some reason)
bob

[paul123]

Re: Dell E193FPp problem

Thanks for the replies. I will try and get a better picture of the board soon.

Took another look at this monitor, when the CCFT's go out the windows desktop is still on the screen, does that indicate there is only a problem in the inverter section of the board?

I tried checking a couple of the components that are being cooled by heatsinks, two are ok, they are simple diode arangments, but one I could not test is a high speed voltage switch mosfet, part no. STP9NK70ZPF.

Any ideas how I can do a reliable test on the mosfet?

[Bobdee]

Re: Dell E193FPp problem

Thanks for the replies. I will try and get a better picture of the board soon.

Took another look at this monitor, when the CCFT's go out the windows desktop is still on the screen, does that indicate there is only a problem in the inverter section of the board?

I tried checking a couple of the components that are being cooled by heatsinks, two are ok, they are simple diode arangments, but one I could not test is a high speed voltage switch mosfet, part no. STP9NK70ZPF.

Any ideas how I can do a reliable test on the mosfet?

Hi Paul
Looks like your Inverter or faulty CCFL, as to the Mosfet you mention here are 2 links for you, datasheet and mosfet test
http://www.datasheetpro.com/750965_d...datasheet.html
https://www.badcaps.net/forum/showpo...&postcount=240
those pics are needed of both sides of board
bob

[EGuevarae]

Re: Dell E193FPp problem

those pics are needed of both sides of board
bob

Agree. You will get better suggestions after those are posted

[paul123]

Re: Dell E193FPp problem

Hi Paul
Looks like your Inverter or faulty CCFL, as to the Mosfet you mention here are 2 links for you, datasheet and mosfet test
http://www.datasheetpro.com/750965_d...datasheet.html
https://www.badcaps.net/forum/showpo...&postcount=240
those pics are needed of both sides of board
bob

Thanks for the info Bobdee. I took the mosfet out and did a couple of tests, there are no short circuits across any of the pins and there is a 0.4 volt drop across the s-d pins ( diode across s-d ), which seems in agreement with the diagram given in the data sheet you so kindly supplied.

However I don't think that is a sufficient test for a mosfet. I haven't been able to find a replacement for this component ( UK ) yet, but I could get hold of the STP9NK60ZPF.

STP9NK60ZPF Vdss of 600V, Rds of 0.95 ohms, Id of 7A and Pw 30 W

STP9NK70ZPF Vdss of 700V, Rds of 1.2 ohms, Id of 7.5 A and Pw 35 W

It should be ok using the STP9NK60ZPF, even if its for testing

There are a few caps I will change as well.

If that fails, then would one of these universal inverter boards do the trick?

If so I will purchase one along with a few CCFT's just incase.

[paul123]

Re: Dell E193FPp problem

Agree. You will get better suggestions after those are posted

I'll try and get a photo of the pcb tomorrow.

[EGuevarae]

Re: Dell E193FPp problem

If that fails, then would one of these universal inverter boards do the trick?

I've done that. But a pic would definitely help to answer that.
But..... if we set aside the size factor, it can be done. Just watch out for the signals coming into your inverter (BLON ,GND and 5/12v) and wire accordingly.

[Bobdee]

Re: Dell E193FPp problem

However I don't think that is a sufficient test for a mosfet. I haven't been able to find a replacement for this component ( UK ) yet, but I could get hold of the STP9NK60ZPF.

What makes you think there is something wrong with this mosfet???
It sounds like this mosfet is on the P/Supply, with you getting image after backlights go out says to me that P/S is good
the fets you will be needing to check are the ones on back of board for the inverter probably, they will be smd packages with either the 3 pin type or the 8 pin
without pics members will be reluctant to work blind
bob

[EGuevarae]

Re: Dell E193FPp problem

without pics members will be reluctant to work blind

[paul123]

Re: Dell E193FPp problem

What makes you think there is something wrong with this mosfet???
It sounds like this mosfet is on the P/Supply, with you getting image after backlights go out says to me that P/S is good
the fets you will be needing to check are the ones on back of board for the inverter probably, they will be smd packages with either the 3 pin type or the 8 pin
without pics members will be reluctant to work blind
bob

You are right Bob, the mosfet above is on the PS side there are two FETs on the back of the board - part no P5506BGD, the 3 pin type.

[paul123]

Re: Dell E193FPp problem

Here are the images of the pcb, front and back.

http://img196.*************/img196/668/dscf2319.jpg

http://img196.*************/img196/6850/dscf2321e.jpg

[lucky13]

Re: Dell E193FPp problem

Your board looks like new?

From my experience, if light blacks out after a few swconds, then there is a high possibility that one of the backlight is defective. The inverter board always shuts off the lamps if it detects a open lamp condition.

I keep a spare, good lamp I pulled out a bad screen for quick testing. I swap out the lamp one at a time and see which one I can swap out to make the lamps stay on.

Otherwise, it will be very difficult for you to know is it inverter or is it backlight.

[EGuevarae]

Re: Dell E193FPp problem

Your board looks like new?

From my experience, if light blacks out after a few swconds, then there is a high possibility that one of the backlight is defective. The inverter board always shuts off the lamps if it detects a open lamp condition.

I keep a spare, good lamp I pulled out a bad screen for quick testing. I swap out the lamp one at a time and see which one I can swap out to make the lamps stay on.

Otherwise, it will be very difficult for you to know is it inverter or is it backlight.

I agree. No visible caps bulged or leaking.
I agree also on the bad lamp thing. Did you notice any noise, like voltage arcing? That could be your problem.

[paul123]

Re: Dell E193FPp problem

Lucky I think the monitor has not been used, if it has, then it hasn't seen much usage at all.

When I switch the monitor on, both CCFT's do light up, and when they go out there is a low buzzing noise, sounds like the transformer(s).

I'm after getting hold of a universal inverter board, for testing, so I will buy a couple of tubes as well.

[LCDrepairllc]

Re: Dell E193FPp problem

YOur lamps are probably fine. THere are usally cracks or bad solder around the legs of the ccfl transformers.Also inspect for cracked solder pads on the legs of he output side of the ccfl transformers. ( very hard to tell unless you wigggle each leg.) I would inspect all solder in this area. Also in the worst case the upper ccfl transformer is usally bad due to heat buildup in the upper part of the case. In that case we sell the whole refurbished board. www.lcdrepair.us

[EGuevarae]

Re: Dell E193FPp problem

YOur lamps are probably fine. THere are usally cracks or bad solder around the legs of the ccfl transformers.Also inspect for cracked solder pads on the legs of he output side of the ccfl transformers. ( very hard to tell unless you wigggle each leg.) I would inspect all solder in this area. Also in the worst case the upper ccfl transformer is usally bad due to heat buildup in the upper part of the case. In that case we sell the whole refurbished board. www.lcdrepair.us

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