Panasonic tx-55650b

[modstation]

Hi
I have a panasonic tx-55as650b lcd tv which all of a sudden lost its picture, but the backlight was still on. All p/s voltages are good and there is voltage on the output of the t con board. I bought a replacement motherboard and with this one in place there is no backlight the SRV-VLED remains at 24 volts (original m/b switches it to 46v) there is no voltage at srv 12v for t con and the green power led blinks rapidly before going solid. when i remove the ribbon to the panel on one side the other side has vertical lines of various colours which disappear when the ribbon is plugged in. Anyone have any pointers? thanks in advance for any help

with original m/b in place t con voltages are as follows: v_in 12v
vdd 0v
vgh -0.2v
hvdd 0v
vcc 3.3v
vgl -5.1v
vcore 1.2v
vep 1.8v
gclk 1.6v
mclk 0.1v
gst 0v
eo 0v
gip_bypasson 0v
vcom top 0v
vcom bottom 0.1v
vst -5.1v
vgh_even -5.1v
vgh_odd -5.1v
clk1 through clk6 -5.1v

[Moreno83]

Re: Panasonic tx-55650b

So with the original mainboard the tv turns on , has backlight but no picture?

Does the tv turn on with the replacement board or is it "dead" ? If the backlight stays on then i think you have a problem with the t-con.

[modstation]

Re: Panasonic tx-55650b

i bought a new m/b and a new t con. with the new m/b no backlight and no 12v on the test point between lvds to tcon so i am guessing its no good. with old m/b and new t con no change just backlight. i took off one ribbon to panel and the other side just has vertical lines. when you switch between sources on tv the backlight changes brightness. I have a feeling panel is bad but not sure how to test to find out for sure.

[Moreno83]

Re: Panasonic tx-55650b

Hmm , strange! You sure the new t-con is good?

Here you can download the service manual.



Wait for the "processing" on the bottom of the page to disappear. It will change to " get manual ".

Go to page 21 and do the self check. Hope this helps you.