DELL E177FPb im ready for my first troubleshooting! need your help!

[pr0cess0r]

I dont know where to start. The monitor is a Dell E177FBp, i changed 2 caps to make it power one now its have 2 sec to black.

I tested it with an other panel and it do the same but tale a little longer.

Here are the pics, i dont know what to do now?







i changed C821 only

IC801 = 66clcem, tl1451acn

IC601= 1200AP40, CPCD, 0618G

I have a DVM and a scope but i dont know how to use it yet!

thx for your help!

[PlainBill]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

I dont know where to start. The monitor is a Dell E177FBp, i changed 2 caps to make it power one now its have 2 sec to black.

I tested it with an other panel and it do the same but tale a little longer.

Here are the pics, i dont know what to do now?







i changed C821 only

IC801 = 66clcem, tl1451acn

IC601= 1200AP40, CPCD, 0618G

I have a DVM and a scope but i dont know how to use it yet!

thx for your help!

Replace the rest of the electrolytic caps with name brand, low ESR caps such as Panasonic FR, FM, or FC. Resolder all the transformers.

PlainBill

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

thx i will order all new caps and change them !

[retiredcaps]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

1) What is that "crud" on cap C702?

2) With power off and lcd unplugged, measure across the secondary inverter transformer pins with your multimeter set on 2000 ohms.

The pins on the backside will be the ones "leading to" yellow high voltage capacitors. You should get a reading the 250 to 800 ohm range as a guess.

Measure all 4 and report the findings.

Normally, I would mark it up on supplied picture, but I'm having a bit of a difficult time mapping it spatially (maybe because I had to get up at 4:40am this morning).

[alexanna]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

1) What is that "crud" on cap C702?

I wonder if that my be Dielectric grease,Looks like there is some on the heat sink also.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

it is heat sink compound like on computer cpu . i will test those inverter today. Do i test acros high voltage output?

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

all transformer read 285 ohms at output side.

[retiredcaps]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

all transformer read 285 ohms at output side.

That sounds about right for a Benq style board.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

I got my ESR meter a nice Peak atlas ESR+ model ESR70. all caps have a good esr but the mF reading is low.470 are 442 and have a .02 esr. i thonk i will not replace them all

[retiredcaps]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

If the caps tests okay and the inverter transformer are okay, that leaves the ccfls or its wiring as possible suspects.

See

http://s807.photobucket.com/albums/y...klight%20lamp/

for examples.

[alexanna]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

I am unsure why no one has recommended checking the 5707 transistors. On this monitor They can fail and not take the inverter fuse out. If one or more are bad there is a good chance you can find it by hooking up one CCFL at a time and then powering on the monitor. Those particular CCFL connectors will not even briefly light the CCFL.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

i will try only one ccfl at a time to see what happen. and test the transistor i have a nice new tester for this !! :P

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

its stupid i have a nbice dca55 tester and dont know how tu use it but all transistor have a different Hfe value.

1:
Hfe=295
2:
Hfe=426
3:
Hfe=338
4:
Hfe=372

[retiredcaps]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

but all transistor have a different Hfe value.

1) See this article ...

http://ezinearticles.com/?Problem-in...tor&id=1049341

2) What about a simple test for a short on the c5707? Test for a short on pins 1-2, 1-3, and 2-3.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

no short at all!

look like the Hfe is too low according to this article!

[smason]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

no short at all!


look like the Hfe is too low according to this article!

Love that Peak 55 tester.


My stock of ebay special 5707s measure 365-373
A few non-shorted 5707s that I removed from monitors (I tend to replace 'em all, I figure the ones that don't fail are often stressed) are 298-330.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

i ordered a ebay repair quit for benQ screen that have 4 5707 and the fuse! the poowersupply new cost 20$ but its fun to fix it myself!

[Lumberjack777]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

i ordered a ebay repair quit for benQ screen that have 4 5707 and the fuse! the poowersupply new cost 20$ but its fun to fix it myself!

Yes it is a lot funner, and usually less expensive.

You also needed to check the 2 FET's located at Q812 and Q805. I fixed a similar board earlier today, and one of the FU9024N FET's was shorted. Hopefully your repair kit includes those.

I ended up having to replace a shorted C5707, a shorted FU9024N, and the fuse at PF801 was blown also.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

Yes the 2 fet are included in the kit ! nothing is shorted there but the transistor have a low Hfe value that can be my trouble i wil replace all 6 component to be safe.

[pr0cess0r]

Re: DELL E177FPb im ready for my first troubleshooting! need your help!

No result from replacing those parts. i will finish my recap even if those elite test ok i dont like theme ! its alays 2 sec to black i try ccfl one by one same result. is there a way to force the inverter to stay on and know if it can be one of the ic that is bad ?