Dell E207WFPc

[killian6pk]

Could not find anything on this monitor doing a search in the forum. This monitor is really nice so I would like to repair it if possible.
I have replaced all caps with low ESR good brands Panasonic, Nichicon etc.
I have checked all fuses and they are good. Also checked all resistors and small diodes. I am down to two Schottky (I think) Diodes and one mosfet (I think) on Heat Sinks.
I need some help in checking the readings I have gotten, to see if these parts are good or not.

Diode Setting on DMM

D906 Schottky #1 Pin 1 - 2 = 1.99v after hitting this reading the meter flips to O.F
2- 3 = .242v

D905 Schottky #2 Pin 1 - 2 = 1.621v
2 - 3 = .148v

Ohms setting on DMM
Q901 Mosfet G - S = 9.99 Kohms
G - D = 8.19 Mohms
S - D = 8.19 Mohms

Thanks for the help.

[retiredcaps]

Re: Dell E207WFPc

D906 Schottky #1 Pin 1 - 2 = 1.99v after hitting this reading the meter flips to O.F
2- 3 = .242v

D905 Schottky #2 Pin 1 - 2 = 1.621v
2 - 3 = .148v

Ohms setting on DMM
Q901 Mosfet G - S = 9.99 Kohms
G - D = 8.19 Mohms
S - D = 8.19 Mohms

1) All those readings are good. It looks like your multimeter has a threshold of 2V for diode testing before it reads 0L (out of range).

2) It always helps if you tell us the problem and symptoms.

3) Good clear pics.

4) NR901 (backside) looks like it has dodgy solder cracks?

[killian6pk]

Re: Dell E207WFPc

Sorry about that. I realized about 1:00 am that I had not given the problem.
The monitor does not power on at all, no light or flicker or anything. I will check the component on the back of the board and get back to you on what I find. Thanks for giving me the info on the front side components.

[retiredcaps]

Re: Dell E207WFPc

1) What is the DC voltage across the big cap? Be careful measuring this as it could be around 165 V DC.

2) What is the DC voltage across the startup cap (C908)? Is it steady or fluctuating?

3) On the backside, what is part number for IC901? For bonus points, find the datasheet and provide a link.

[retiredcaps]

Re: Dell E207WFPc

4) On the multicolored connector, measure all pins for DC voltage. Report the pin number, its legend (if any), and the voltage.

[killian6pk]

Re: Dell E207WFPc

Voltage Across Big Cap = 173v

Connector Label Reads:
Black = N/F
Open (no wire) = NC
Brown = DIM
Open = +14v
Open = +14v
Red = 5v
Orange = 5v
Yellow = Gnd
Green = Gnd

Voltages from Green Gnd. Readings taken with Power Pluged In and On.
Reading taken from Power Supply Side Plug
G - Y = 0v
G - O = 5.08v
G - R = 5.08v
G - B = -288 mv

Voltages taken from Green = Gnd on Power Supply Side Plug to Main Board Plug
G - O = 5.08v
G - R = 5.08v
G - Y = 0.06mv
G - B = 1.3mv

C908 is 10.12v Steady
IC # is: EA1530A
DataSheet is at: http://pdf1.alldatasheet.com/datashe...TEA1530AP.html I need all the extra points I can get. Thanks

[Rtech]

Re: Dell E207WFPc

At a quick glance, all looks as it should, so probably need to switch your attention to the Logic Board, particulary the Voltage regulators,so if you cannot identify them, then you need photos of the top of the Board

[killian6pk]

Re: Dell E207WFPc

Ok, I'll get pictures. Cloudy, Rainy and getting dark here. I will post asap in the morning. Thanks.

[retiredcaps]

Re: Dell E207WFPc

1) Those DC voltages indicate your SMPS is working.

2) Now we need a clear focused picture of the logic/main board.

3) Rtech beat me to it.

[killian6pk]

Re: Dell E207WFPc

Ok here are the two Video Board Pictures. Sorry about the flash. It is still a nasty day today. So I had to improvise the picture taking.

[trebo]

Re: Dell E207WFPc

Ok here are the two Video Board Pictures. Sorry about the flash. It is still a nasty day today. So I had to improvise the picture taking.

Is that a solder splash across pins 1+2 on U402?
also can you post data on the 3 pin component? just under and to the right of U402 as flash has obscured it

[retiredcaps]

Re: Dell E207WFPc

1) Interesting. Did you recap this main board too? Or did it come with Rubycon and UCC KY caps?

2) The voltage regulators are circled in red. We want the DC voltage readings from all the 3 pins (Gate, Source, Drain) with respect to ground.

[killian6pk]

Re: Dell E207WFPc

Is that a solder splash across pins 1+2 on U402?
also can you post data on the 3 pin component? just under and to the right of U402 as flash has obscured it

Solder splash appears to only have been on top of U402 not between legs.

The component you are referring to is Q401 and the number is AZ1117D. Here is the datasheet: http://pdf1.alldatasheet.net/datashe...1117D-1.8.html

[killian6pk]

Re: Dell E207WFPc

1) Interesting. Did you recap this main board too? Or did it come with Rubycon and UCC KY caps?

2) The voltage regulators are circled in red. We want the DC voltage readings from all the 3 pins (Gate, Source, Drain) with respect to ground.

I make it a habit of never touching a main board unless I absolutely have to. They are so hard to remove components from. I don't know if someone tried to work on this board before I got it. Picked it up off of Craigs List.

I will get your readings on what you have circled. Get back to you with those soon.

[retiredcaps]

Re: Dell E207WFPc

I make it a habit of never touching a main board unless I absolutely have to.

Hmm, now that I relook at the backside, it looks like the original caps from the soldering.

You almost never see high quality caps (especially low ESR) on the logic board since they don't undergo the same stress as caps on the SMPS.

[killian6pk]

Re: Dell E207WFPc

1) Interesting. Did you recap this main board too? Or did it come with Rubycon and UCC KY caps?

2) The voltage regulators are circled in red. We want the DC voltage readings from all the 3 pins (Gate, Source, Drain) with respect to ground.

Do you mean for me to take the readings with the power on and the main and power boards connected.

[killian6pk]

Re: Dell E207WFPc

Hmm, now that I relook at the backside, it looks like the original caps from the soldering.

You almost never see high quality caps (especially low ESR) on the logic board since they don't undergo the same stress as caps on the SMPS.

I believe you are correct. The solder points look just like factory work.

[retiredcaps]

Re: Dell E207WFPc

Do you mean for me to take the readings with the power on and the main and power boards connected.

Yes.

[killian6pk]

Re: Dell E207WFPc

Readings on component (with heat sink)
G = 2.2mv S=5.07v D=3.28v

Q401
G=2.0mv S=3.28v D=1.79v

Just for my knowledge, I thought you read transistors (Q401) by taking an ohms reading between the different legs G-S G-D & S-D.

[retiredcaps]

Re: Dell E207WFPc

Readings on component (with heat sink)
G = 2.2mv S=5.07v D=3.28v

Q401
G=2.0mv S=3.28v D=1.79v

The readings for the voltage regulators look good. The "usual" voltages are 1.8V and 3.3V.

Just for my knowledge, I thought you read transistors (Q401) by taking an ohms reading between the different legs G-S G-D & S-D.

Yes, that is one test. Voltage regulators can be shorted. However, the test for a short doesn't verify if it outputting the correct voltage or not.

For example, a AL1117-33 regulator should output 3.3V DC. The suffix -33 denotes the output voltage.