Hisense H6750G stumped on this

[Diah]

Re: Hisense H6750G stumped on this

2 possibilities
1- you may have one or more short LED BL
2- Main Boards issue / firmware could be

explaining
Step down circuit .. PSU at STB standby status generate via line 12 V 7.8-10 V..... the step down on MB generate 3.3V to let the MB start script SPI Flash working and sending this 3.3V back to PSU to turn it on.... PSU will go high... mean the 7.8-10 V will be 12 V.

but if PSU register over load at LED BL will report or some design it will handle the issue self and turn off the BL.

but the IC you remarked it become hot on MB,, its belong to T.con 12 V. rail t delivered to T-CON from MB via LVDS

as you said no change... keep the LVDS disconnected from MB side.... make wire jumper from 12V PSU socket direct to T-CON fuse... then turn on... see if the screen under tourch light generate color pattern... to be sure we have t_CON and panel are fine.... .... you can use too yours led testers to light on one group only of BL to see if screen work with out issue.

other wise i will go to take screen apart and check LED if all lit on.... if yes then screen test if yes too nothings more only working on MB or replace it

[EazyBone]

Re: Hisense H6750G stumped on this

That does seem very hot for a voltage regulator, check those little caps right by it, are any shorted, also what do you get measured in ohms?

None shorted ,

C33/34 26.1 ohm
C32/29 38 Kohm

[EazyBone]

Re: Hisense H6750G stumped on this

Here's tcon, I normally seen fuses lol can someone point out where the fuse is? I don't see one at all

[Diah]

Re: Hisense H6750G stumped on this

on the right side the black on with T written on it as called on print F1

[EazyBone]

Re: Hisense H6750G stumped on this

on the right side the black on with T written on it as called on print F1

Lol I did this and it worked lol. Saw red and green and bunch of colors. Well I need practice pulling apart a TV for the 1 millionth time lol so yea.

I hate ripping these apart lol

[Diah]

Re: Hisense H6750G stumped on this

good.... then follow one by one

1- check the lvds cable between MB and T-con from both side if the contact pins didn't broken or short if okay....
then

2- take screen apart carefully to check with urs eyes if led bl all turn on not there shorted or off
if okay...
3- replace MB or work on it

[EazyBone]

Re: Hisense H6750G stumped on this

good.... then follow one by one

1- check the lvds cable between MB and T-con from both side if the contact pins didn't broken or short if okay....
then

2- take screen apart carefully to check with urs eyes if led bl all turn on not there shorted or off
if okay...
3- replace MB or work on it

I took this 75 inch screen off alone lol... And the friggin LEDs are fine. Scared to try and put the screen back on. Biggest one I've messed with now. Wish me luck. At least we are down to the last things lol. Mother friggin board.

Any suggestions what I should be checking for? Obviously continuity but I've not been successful at fixing a MB yet. I've heated one with the main chip up and put it back in and had picture for a moment but that was it. Okay back together

[Diah]

Re: Hisense H6750G stumped on this

MB fixing are levels depend on the fault,,,,, for me personalty at any level i do determine the fault on it... if it goes to HW... my way to replace it,, but you can try... if yours eyes still in good young range lol

[EazyBone]

Re: Hisense H6750G stumped on this

Here's MB pic, I can't find anything wrong here. No shorts that I find. Is there some area I should look at? They don't have this MB online anywhere. Crazy

[Diah]

Re: Hisense H6750G stumped on this

you need to check
1- LVDS connected.... check if T-CON fuse F1 have 12V from both side... if no V.
then disconnect the wifi / BT module from MB and check again. if still no V

you need to check the Regulator you said before its go hot read the V on all pins Ref to chassis

i think you have Service port on the side between USB port and HDMI , if this service port need to capture the log at start up the tV

also from ypurs post the 18V rail it read 16V... slide out the wire of it from PSU side. and turn on check the pins of it if it go high to 18V.

[nomoresonys]

Re: Hisense H6750G stumped on this

Yep, check GH12E voltages, don't think it should run that hot.

[nomoresonys]

Re: Hisense H6750G stumped on this

Great pitures bytheway, these detailed pictures are a fine example of what's needed by the helpers.

[EazyBone]

Re: Hisense H6750G stumped on this

Gh12E gets 0v, 3.28, 5.1 and opposite side gets 3.28

TV won't turn on but Tcon doesn't get any V to fuse on either side, with or without WiFi disconnected

I don't see a service port, there's a headphone jack between HDMI and USB

Yes 18v reads 16.6 actually . I don't know what you mean slide out the wire and check for 18V. Do you mean disconnect it from the harness as a single wire?

Here's some pictures Sony lol

[EazyBone]

Re: Hisense H6750G stumped on this

Update 2 seconds later Lol

I touched this specific cap to test voltage out of the other area that's getting hot and when I did the backlight flickered and then turned on. I didn't have time to check other voltages, but I was able to check one 18v pin and it had come up to 16.8v before I realized I did something. Help now???? Lol

Now the TV red standby light doesn't come on anymore lol and voltages are now back to main disconnected from mb voltages

Now everything is dead lol. I shorted something touching that exact area or something.

As a note the 4R7 component was getting hot and is the other hot spot seen in thermal. Only 115F but still hot compared to other 4R7

[Diah]

Re: Hisense H6750G stumped on this

disconnect MB from PSU and check which V you have on the socket

[Diah]

Re: Hisense H6750G stumped on this

by the way the marked part you touched are R not C..... if you shorted with chassis possible one of the R get Open

[EazyBone]

Re: Hisense H6750G stumped on this

disconnect MB from PSU and check which V you have on the socket

They are 12v (is 10) 18 v (is 14)

Hisense 272945 is board and literally no one has it lol. The luck

[Diah]

Re: Hisense H6750G stumped on this

I don't see a service port, there's a headphone jack between HDMI and USB

you have service port.... what about close to tuner i can see there are R connected to the jack as rx tx gnd

[EazyBone]

Re: Hisense H6750G stumped on this

you have service port.... what about close to tuner i can see there are R connected to the jack as rx tx gnd

You are correct, I never knew they looked that way. Wouldn't even know what to do with it.

I think we are dead now, no replacement available currently so I'm gonna mess around with it but I think it's done lol. At least verified that it was the motherboard most likely and will keep in case I run across one.

[nomoresonys]

Re: Hisense H6750G stumped on this

So the tcon fuse is good, showing continuity with a probe on each end, but you have no 12 volt on either side? then no voltage getting to tcon.