Emerson LC320EM2 back lights on but no picture

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

0.00v on the left pin and 8.1v on the right pin with the power on.

[tom66]

Re: Emerson LC320EM2 back lights on but no picture

OK can you re-measure the voltage on both ends of the fuse on the T-con, it could be a break in the cable because the main board is turning the supply on to it.

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

Getting .23v on both ends of the fuse.

[tom66]

Re: Emerson LC320EM2 back lights on but no picture

You have a break somewhere in the cable, then. I think that is your problem.

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

the LVDS or power cable?

[tom66]

Re: Emerson LC320EM2 back lights on but no picture

The LVDS.

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

I would probe each end of the connector to confirm its the cable but with my old shaky hands I would probably short out the TV lol

thanks

[audiofreak19]

Re: Emerson LC320EM2 back lights on but no picture

I would take the lvds cable out completely and do a continuity test to make sure there is full connection through all pins in it.

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

With my meter set on 20k ohm I get 002 on the first three pins of the cable and 1 on all the rest.
Either my cable is bad like tom66 suggests or my harbour freight meter is possibly bad.

[tom66]

Re: Emerson LC320EM2 back lights on but no picture

Sounds like a bad/open cable, perhaps it has been damaged by too much flex or being torn out? It is unusual for so many connections to fail.

[bammbammfran]

Re: Emerson LC320EM2 back lights on but no picture

with the unit powered on, did anyone confirm voltage on the first 4 pins of the 30 pin flat ribbon on the main board side at CN3002 or at not installed c3047 cap pins ?

NEVER MIND I see that it was 8.1 (seems like an oddball voltage though ??)
The last picture looks like the flat ribbon might not be fully seated ? Check those pins on the ribbon and reseat it for giggles and if that 8.1 still doesn't make it to the lcd board at the green fuse, you may want to jump a wire to verify the ribbon being an issue.

There is one model of acer that used to always loose contact on these pins at the screen end of the plug. the pin actually usually discolor and sometimes burn off

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

I tried jumping the fuse with a wire and it didn't make any difference.
Also I tried taking a reading of the first 4 pins on the top board (t-con) part of the cable. With the tv powered on I got no voltage reading on any of the pins.

edit: Oops I see where you said I should measure on the main board side. I will remeasure and report back.

thanks

edit 2: looking at the back of the TV from left to right the first 4 pins of CN3002 all measure 8.1v

[bammbammfran]

Re: Emerson LC320EM2 back lights on but no picture

ok
so the power is not traveling through the ribbon
run a wire from either the 4 pins on one side to the other 4 pins
or
from the c3047 + pin to the green fuse on the side that is closest to the 30 pin connector if that is easier

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

bammbammfran
I ran a wire from the + c3047 to the right side of the green fuse and it caused a puff of smoke and fried IC3010 (now has a burn hole in it)

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

Since I had a spare (bad) main board from this TV I swapped out IC3010 from the old bad board to the one I just shorted out.
Now I am getting 11.9v at the + of C3047 but still am not getting any volatge to the green fuse on the top board.
I tested the fuse to make sure it wasn't blown and it read 000 ohms. that means its good right?

I don't know if I repaired the main board properly or not, but I have a LVDS cable ordered from ebay and fingers crossed am hoping it fixes the TV.

thanks

[bammbammfran]

Re: Emerson LC320EM2 back lights on but no picture

I had a gut feeling that the 8.1 was not the correct amount
12 makes more sense even though I do not know exactly what it should be.
I'll have to see if I can find a datasheet on the panel
the wire jumper must have taken the last oomph it had in it
possibly the draw needed by the screen was too much for it???

[bammbammfran]

Re: Emerson LC320EM2 back lights on but no picture

Hum
Off the wall model ?? Funai UK32BXA
any numbers on the board at the top of the lcd panel

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

kinda hard to make out but here's a pic of the numbers on the top board.

[bammbammfran]

Re: Emerson LC320EM2 back lights on but no picture

that helped, took me to the glass face instead of a complete panel
looks like 12v

Panel Brand : BOE
Panel Model : HV320WX2-201
Panel Type : a-Si TFT-LCD , CELL
Panel Size : 31.5 inch
Resolution : 1366(RGB)x768 , WXGA
Display Mode : AFFS, Normally Black, Transmissive
Surface : Antiglare (Haze 10%), Hard coating (3H)
Brightness : 0 cd/m2
Contrast Ratio : 1200 : 1 (Typ.)
Display Colors : 16.7M (8-bit)
Response Rime : 8 (Typ.)(G to G)
Viewing Angle : 89/89/89/89 (Typ.)(CR≥10) (L/R/U/D)
Frequency : 60Hz 120Hz (60HZ Input) : Embedded MEMC Circuit 120Hz+120Hz : 120Hz Panel+120Hz Backlight 240Hz (60HZ Input) : Embedded MEMC Circuit]
Lamp Type : No B/L [8S6P: 8 Serial, 6 Parallel]
Signal Interface : LVDS (1 ch, 8-bit)
Input Voltage : 12.0V (Typ.)

[Gorrillasnot]

Re: Emerson LC320EM2 back lights on but no picture

hopefully when my ebay LVDS cable arrives it fixes it.
fingers crossed.

thanks