e550vl no picture or backlights

[johns1mj]

Read through the other posts and have concluded I have a bad main board. I wanted someone to double check my information to make sure I didn't miss anything.

Symptoms- 1)No backlights 2) No picture even with flashlight.

When powered on-

Power supply
CN201 connector on the main board has all correct voltages except the C labled pin which only has .763 volts when on. I assume this is supposed to be between 1.5 and 3 volts for normal backlight on operation. Pin A has 2.814 volts.
CN202 has .763 volts on pin C and 3.209 volts on pin A. The 24 volts pins are correct.
CN203 has A,B and C slots empty. The 24 volts are present on pins.

CN204 has both 18 volt references.
Master
CN24
2)stnby 0.294
3)on/off 2.95
6)SRT 2.815
7)ctsync out 1.988
11)ss 3.074
Pins 1,4,5,8,9 and 10 are 0
CN1
Pins 1-5 are 24.26
Pins 6-10 are 0
Pins 11 and 14 are empty
Pin 12 3.209
Pin 13 .763
Slave
CN201
Pins 1-5 are 24.26 volts
Pins 6-10 are 0 volts.
If I remove the "C" pin on power supply CN201 the backlight will turn on. Still no picture.

Please advise any fault in readings or test procedure.

Was able to get it over to a hdmi port and it has sound.

[johns1mj]

Re: e550vl no picture or backlights

did the 5 volt to back light on test and the back light come on but still no picture. Any thoughts?

[Andrew F. Ali]

Re: e550vl no picture or backlights

Looks like a bad T-CON Bd. from what I've read. Is the T-CON Bd separate from the panel?? However, I'll wait for the others to chime in, first.

[johns1mj]

Re: e550vl no picture or backlights

It is the same board. I don't know if I blew the tf1 fuse while testing or if I missed it originaly. I replaced it and there were lines on screen for about 1 second and then the fuse blew again.

[dskall]

Re: e550vl no picture or backlights

You would need to find reason fuse is blowing

[budwich]

Re: e550vl no picture or backlights

unplug one "half" of the tcon to panel cables.... see if the fuse blows ... assuming you have more... :-) try the other half. See if the panel comes up without blowing the fuse on "half tcon".

[johns1mj]

Re: e550vl no picture or backlights

it took out the tc2 resister next to the f1 fuse.

[Andrew F. Ali]

Re: e550vl no picture or backlights

I am still unsure if the T-CON Bd is separate to the Panel. If it is separate, replacing the T-CON Bd would remedy your problem.

[johns1mj]

Re: e550vl no picture or backlights

T-con is part of the main/input board

[ecking767]

Re: e550vl no picture or backlights

I have repair this model Vizio before, and sometime found shorted caps and the main IC chip to shorted. you are in the right area for troubleshooting if the fuse keep blowing

I will check the cap and regulator I have highlighted in red

[Andrew F. Ali]

Re: e550vl no picture or backlights

Replace the old Bd with an new one, since that is the case.

[ecking767]

Re: e550vl no picture or backlights

Replace the old Bd with an new one, since that is the case.

this model main board is very hard to find, no one has it, and when you do find one for it will be very expensive.