Dell E173FPf

[goofy173]

I've got 2 of these things sitting around. Lamps aren't coming on but the display is working. I checked the caps and they look good. Replaced them on one to make sure. No difference. What do I look for next? The 2 Transformers? Anyone have a real schematic for these?

[sceva]

Re: Dell E173FPf

Welcome to the forum.

First search for E173* and read some of the other posts to get an idea of some of the common repairs are for this model.

Second, take some pics and post them, front and back of boards. Tell what brand of replacement caps you used.

The better info you provide the better help we can be!

[goofy173]

Re: Dell E173FPf

I didn't find much help here searching because not many are talking about the Fpf's. The 2 caps I used are ICC brand. I also replaced that Q850 MOSFET or whatever it is as it was bad. Check all around that for damage or bad solder joints and found nothing. It's almost up to brightness on the right side, with obvious dimming on the left.

The 1st pic was before I changed the caps which are shown on the left side of the board, between the transformers.

[uligli]

Re: Dell E173FPf

At first place you should check the CCFL lamps, if they are working then check the inverter board.

[goofy173]

Re: Dell E173FPf

OK. Check the lamps as in how?

BTW, I have 2 monitor screens. Both look just alike connected to this board.

I was working with our electrician and he wanted to test the voltage to the lamps. However just placing one lead of my Fluke 87 on the blue wire going to a lamp, shut them both off. Cycling the power turns them back on. We poked everywhere on the board with no difference so I don't believe this to be a bad connection.

[goofy173]

Re: Dell E173FPf

Thought the pics disappeared. Bad post.

[goofy173]

Re: Dell E173FPf

Try these pics again.

[PlainBill]

Re: Dell E173FPf

Lots of problems here.

1. You said "Lamps aren't coming on but the display is working. " Your latest post contains a picture of a working LCD panel. Please give a little more detail. Do you have two panels with one good board and one bad one??

2. The pictures of the board just won't do. I've attached a picture of a similar board. That's the quality of picture we need (OK, the glare from the lamp / flash isn't helpful).

3. There are three ICs between the two inverter transformers. Two are the transformer drivers, the third is the inverter controller. What is the part number of the inverter controller?

4. Statements like "I also replaced that Q850 MOSFET or whatever it is as it was bad." and "The 2 caps I used are ICC brand." aren't really helpful. The pictures you posted are so poor we can't figure out where Q850 is!

5. You also indicated the lamps were working when you probed them with a Fluke (really bad idea, by the; you are dealing with move than 700 VAC).

Above all, what are the symptoms with the bad board? IS there any sign that the lamps are coming on, even for a brief second?

Remember, while you know exactly what you did and what you see, you must convey that information to us, or we can't help you. We don't have crystal balls. (Although I suspect one or two have brass ones).

PlainBill

[sabre504]

Re: Dell E173FPf

Hi hope this helps have same board floating around

RED = U1 0Z9RRAG
0403A1
33248032

Yellow = U3 9960D
412203

BLUE = U2 9960D
408143

[PlainBill]

Re: Dell E173FPf

Hi hope this helps have same board floating around

RED = U1 0Z9RRAG
0403A1
33248032

Yellow = U3 9960D
412203

BLUE = U2 9960D
408143

Oh, crud. One of them. I got lots of hits, but no datasheet. Also a confirmation that it is equivalent to an OZ9930, but there is even less information on those.

I'll just have to wait and see if the OP will provide good pictures.

PlainBill

[sabre504]

Re: Dell E173FPf

Will take picture of mine and post if it will help

[Rtech]

Re: Dell E173FPf

Most problems I have come across on all the FPf series, are usually around the PWM chip,However,as that cannot be the case here,it could well be caused by failure of the Schottky Diode(D854..SRF10-10),of which I have had 2 cases,and both times the diode had gone short cct.

[goofy173]

Re: Dell E173FPf

1. Originally the lamps weren't lighting. I replace that Q850 which looks to be a Shottky Diode and now either LCD panel lights up nearly the same as the other.

2. I'll have to bring my camera from home, into work. My cell phone is the best we've got here which is only 2 meg pixel.

3. That is a very small chip. Numbers are hard to read but what I see is:
OZ9RRAG

4. I covered the Q850 in #1. You had asked the about the brand of caps. They are the same 220 µf but higher voltage, which I know makes no difference.

5. The electrician was the one pointing out where to test. I had asked him what voltages we were looking for and he expected 700-800 VAC. The Fluke 87 handles 1000v. If you were meaning safety, I am a Purdue degreed tech and the electrician really knows his stuff.

OK, so the lamps come on, but not at the brightness they should be. I'd say the right side is at about 80% of usable, where the left side is 70%.

[goofy173]

Re: Dell E173FPf

and the replacement caps I used were ICC, International Components Corporation Brand. One is a 50 volt and the other is a 25 volt: Stuff I had laying around.

[goofy173]

Re: Dell E173FPf

Forgot the camera today. Try again tomorrow.

[goofy173]

Re: Dell E173FPf

OK. Here we go.

[PlainBill]

Re: Dell E173FPf

OK, you have continued to confuse me. What is the problem with the monitors?

PlainBill

[goofy173]

Re: Dell E173FPf

Let's just talk about 1 monitor. That's all I want to get out of this.

The Lamps are dim. The left side more-so than the right.

I've replace a blown Schottky diode (Q850) as there was no lighting on this monitor originally. So then I replace the 2-220 µf caps (only had axial so they fit weird) with new ones, but it did not change the brightness level.

[PlainBill]

Re: Dell E173FPf

Let's just talk about 1 monitor. That's all I want to get out of this.

The Lamps are dim. The left side more-so than the right.

I've replace a blown Schottky diode (Q850) as there was no lighting on this monitor originally. So then I replace the 2-220 µf caps (only had axial so they fit weird) with new ones, but it did not change the brightness level.

Ahh!!! Thank you, that clears things up.

Q850 isn't a Schottky diode, it's a mosfet.

It's a long shot, but have you checked the brightness setting? Also, the output voltages of the power supply?

Normally the lamps run horizontally across the monitor If that is true on this monitor the output voltage of the inverter is quite low, the CCFLs are only lighting over half their length. If they are mounted vertically, one set is getting much less voltage, that would indicate a problem with one side of the inverter.

Try to position the power supply / inverter/ logic card so you can reverse the inverter connections - hook the wires that normally connect to CN1 and CN2 to CN3 and CN4, then try it. Does the shading switch sides?

PlainBill

[goofy173]

Re: Dell E173FPf

OK on the MOSFET. Early in posting I had put that it was a MOSFET but I looked it up and thought it said it was a Schottky.

When I did check the brightness and contrast and turned them both up. The brightness would only go up to around 86 before the lamps shut off.

Where do I measure the output voltages of the power supply?

Not sure of the mounting of the lamps. Haven't had it far enough apart to see. I just assumed they were vertical because of the left side being dark.

I reversed the CN connections and it did not switch sides.