TCL b2610 powers up, backlights on, sound on, no picture

[odgaf]

hi people

i have here a tcl b2610 39 incher led lcd with a blank screen bl- on and sound on
im a nooby fixing tvs but im learning and reading a lot
this tv has a power board and i think a logic board with inbuilt tcon?? [not sure] and 2 boards on the bottom edge of the screen which i think are led drivers or tcon??
ive gone over the caps on the logic board in circuit with my esr meter nothing fishy there, i checked diodes on the power board and found one reading 0.245 voltage drop off which i thought was slightly low, but power seems fine,so im guessing my next step is to take measurements while the set is on but im stuck on how to start doing this, my phone is having trouble uploading pics so ive scrounged some identical ones off the internet till tomorrow when i will update them with the real ones, im purely guessing the logic board is the culprit but realise it could be the panel but nothing ventured nothing gained

ive not yet checked caps on power board but can do if needed






heres the pics i scrounged, remember im a noob and may need to be told put probe here and test etc
the diode that tested low is on top right of powerboard pic

i have hot air and desolder, esr meter and mm equipment on hand

[odgaf]

Re: TCL b2610 powers up, backlights on, sound on, no picture

ok ive been trying to test the 3 large voltage regulators on the logic board while powered on and im getting really weird readings,
u103 top rightish of board
3.2v output
5v input
00.70 adjustment ???

u104 just near tuner
3.3v output
5v input
00.65 adjustment

u803 middle board among caps
1.8v output
5v input
560.0 adjustment

i will update these pics soon

[mmartell]

Re: TCL b2610 powers up, backlights on, sound on, no picture

The regulators are probably fixed output. Take a pic of the back of the set so we can see how the boards are connected together. Check for smd fuses where the connectors are between the main board and the small skinny boards on the bottom. If you find any check them for continuity.

[odgaf]

Re: TCL b2610 powers up, backlights on, sound on, no picture

thanks for the heads up dude, while looking for smd fuses on the lower boards connectors i saw what looked like tiny black marks on the back of one of the white transparent ribbon connectors which join the 2 lower boards,

i took the ribbon cable off and it had some gunk or corrosion covering many of the gold pins on one side and clean shiny pins on the other , im almost thinking its some liquid damage maybe thats come through the bezel, the screen was utterly grubby before i cleaned it with rubbing alcohol.

im going to try to clean the ribbon cable and connector with a toothbrush, but ill wait as im hoping my phone comes today so i can upload some pictures of whats going on with the connector and ribbon
my next question is how easy is it to remove those connectors with hot air, and half an inch from the connector are what appears to be tab bonds im guessing these are boards built into the panel

thanks for your help so far, i would never have seen this if i wasnt looking for fuses, i was focusing on the main board i suspect this tv is junked but i will try and swap or clean the connector and cable and post the pictures as i go

[odgaf]

Re: TCL b2610 powers up, backlights on, sound on, no picture

finally got my new phone, heres the pics

[odgaf]

Re: TCL b2610 powers up, backlights on, sound on, no picture

and here are the pics of the connector and ribbon cable
does this look burnt? it looks like gunk

[odgaf]

Re: TCL b2610 powers up, backlights on, sound on, no picture

so i cleaned the ribbon much as i could and the connector and same blank screen, i disconnected the entire ribbon, still same blank screen
i removed the connector with hot air , it looks pretty screwed, anyone know if this is burnt? i also need to know the name of it so i can maybe source a new ribbon and connector, failing that the boards are pretty cheap from china maybe 10 bucks but how hard are those tab bonds to remove with hot air ??? theres 2 to remove,
im thinking this tv is junk but i have the tools so ill give it a go

heres the pics of the connector i removed is it a standard connector? anyone know the names of them ? aside from liquid what could cause this ?