Dell e171fpb monitor no power or LED lights

[ratnesh3107]

Re: Dell e171fpb monitor no power or LED lights

Viewsonic va1616w Ca1 burn, no power problem, pls sugest ca1 capacitor value.

[PlainBill]

Re: Dell e171fpb monitor no power or LED lights

i have tv vizio vp50-hdtv20A.power good when i turn on . but screen still black .
could you please let me know which board in tv no good .
thank you

There are a number of problems with your post.

1. You posted in the Monitor and computer display section, not the TV section.

2. You hijacked a thread for a Dell monitor.

3. Some of the people here are very good, a few are brilliant. NOBODY can accurately diagnose this problem based on the information you provided.

4. This TV appears to have two problems - power supply failures and buffer failures.

Troubleshooting by replacing boards until you find the bad one is a way to fix a TV - it's an expensive way, but it works - usually.

PlainBill

[sinhnguyen]

Re: Dell e171fpb monitor no power or LED lights

i have tv vizio vp50-hdtv20A.power good when i turn on . but screen still black .
could you please let me know which board in tv no good .
thank you

[Rtech]

Re: Dell e171fpb monitor no power or LED lights

If you mean you have 4 connectors split into 2 Pairs(top & bottom),I don't mark which hole they go into. The length of the cable determines which pair of conectors must be used, and as far as I can remember, it does not matter which hole they are then plugged into as long as they are paired.,

[Rtech]

Re: Dell e171fpb monitor no power or LED lights

Every Monitor I have seen, the backlight connectors ALWAYS only fit into the sockets one way only,otherwise they will not make contact !!

[Th3_uN1Qu3]

Re: Dell e171fpb monitor no power or LED lights

On all monitors i've worked on it's been pink wire up.

[alex.eaglemtn]

Re: Dell e171fpb monitor no power or LED lights

I made a huge error. When disconnecting the screen I forgot to mark which way the back light connectors. Since they can be inserted either way, does anyone know the proper way to insert these connectors. There are two identical connectors. Any help would be greatly appreciated!

[shovenose]

Re: Dell e171fpb monitor no power or LED lights

well you said have the transformer wasnt owrking. afaik thats the prob righ there...

[PlainBill]

Re: Dell e171fpb monitor no power or LED lights

Well, none of the others pins puts out anything.

'Puts out' has such a naughty connotation. I much prefer 'reads 0 volts', or what ever the reading was. Well, we've established the voltage into the IC is low. The two possible causes are the IC is bad, or for some reason the source isn't delivering enough voltage.

The two pictures in post number 7 cover the area I am interested in. I need a sharper picture of the top, and also a good, sharp picture of the bottom of that area.

Alternatively, there are several large resistors on the top side of the board in that area. With power unplugged, check the resistance of each of them and compare it to the color code.

The UC3842 is quite inexpensive - as low as $1.14 each, but I'd rather make sure I have you order the correct part rather than blindly replacing it.

PlainBill

[miamiflorida]

Re: Dell e171fpb monitor no power or LED lights

Probably not. But 13.7 volts is below the startup voltage, but above the shutdown voltage. This MIGHT be due to a bad cap, resistor that has changed it's value, or the IC is working. With power on, CAREFULLY measure the voltage on the rest of the pins, using pin 5 as ground.

PlainBill

Well, none of the others pins puts out anything.

[PlainBill]

Re: Dell e171fpb monitor no power or LED lights

You think the IC is bad ?

Probably not. But 13.7 volts is below the startup voltage, but above the shutdown voltage. This MIGHT be due to a bad cap, resistor that has changed it's value, or the IC is working. With power on, CAREFULLY measure the voltage on the rest of the pins, using pin 5 as ground.

PlainBill

[miamiflorida]

Re: Dell e171fpb monitor no power or LED lights

You think the IC is bad ?

[retiredcaps]

Re: Dell e171fpb monitor no power or LED lights

"Consider it evolution in action" 'Oath of Fealty' by Larry Niven and Jerry Pournelle.

Jerry Pournelle. Wow, that is a name I haven't heard in probably 15+ years. I remember eagerly going to the library everyday looking for the latest issue of Byte magazine to read his column.

[miamiflorida]

Re: Dell e171fpb monitor no power or LED lights

Pin 5 on the UC3842 is ground. Pin 7 is Vcc. What is the voltage from pin 5 to pin 7?

PlainBill

13.7vdc

[retiredcaps]

Re: Dell e171fpb monitor no power or LED lights

No, is a little digital Canon 7m camera, but the zoom is only 4x.

Wow, for a Canon, I expect much more unless it is physically damaged.

Humor me. Try this for future pictures. Set the Canon to its highest picture resolution. Put it on macro mode (usually a flower icon). Turn off flash. Turn off zoom (optical and digital).

Take the board next to the window on a sunny day. Press and hold the shutter halfway. It should tell you on the LCD what the shutter speed is. On a very good day, I can get 1/500 which produce crisp sharp pictures.

Anything above 1/125 should produce quality pics.

edit: The last pic of the backside with the yellow outline box is pretty good, but the resolution is low and it is hard to see all the lettering.

[PlainBill]

Re: Dell e171fpb monitor no power or LED lights

No, is a little digital Canon 7m camera, but the zoom is only 4x.

Pin 5 on the UC3842 is ground. Pin 7 is Vcc. What is the voltage from pin 5 to pin 7?

PlainBill

[PlainBill]

Re: Dell e171fpb monitor no power or LED lights

Testing across the big cap for voltage would have been my next suggestion, but I'm personally hestiant writing instructions when I'm tired near midnight.

Especially instructions that involve mains line voltage. And while the OP probably lives in Miami, Florida as the screen name suggests, I would hate to see anyone experince 240V * 1.4 if they should be from Europe.

I'm more pragmatic. "Consider it evolution in action" 'Oath of Fealty' by Larry Niven and Jerry Pournelle.

PlainBill

[miamiflorida]

Re: Dell e171fpb monitor no power or LED lights

The datasheet for your SMPS is at

http://pdf1.alldatasheet.com/datashe...LD/UC3842.html

Just out of curiousity, is this a 1M or 2M camera phone?

edit: I'm not 100% sure here, but do you have a transformer ring tester?

No, is a little digital Canon 7m camera, but the zoom is only 4x.

[retiredcaps]

Re: Dell e171fpb monitor no power or LED lights

OK, don't know if this is of any help, but I checked for voltage across the IC601 and I'm getting 13.7vdc between pin-6 and all the other pins.

Just so you know I also check voltage on the Transformer (T601) and I'm reading 165vdc on all 4 pins on the bottom side and nothing on the upper side.

The datasheet for your SMPS is at

http://pdf1.alldatasheet.com/datashe...LD/UC3842.html

Just out of curiousity, is this a 1M or 2M camera phone?

edit: I'm not 100% sure here, but do you have a transformer ring tester?

[miamiflorida]

Re: Dell e171fpb monitor no power or LED lights

IC601 is the PCB designation. PlainBill wants you to read the part number off that chip. There is no way we can read that number from those pics.

To get the best pictures, put your camera on macro mode and take the picture next to a window on a sunny day.

Oh ok, this what's printed on it;

CHIN
UC38428
K45323