Toshiba 55ZV650U REGZA sound but no picture

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

The 100K resistor is the part of the RCD snubber circuit for the STBY power supply, so measure that resistor off the board, it is very rare to have bad snubber resistor and if it is open the the STBY will not work properly and SMPS IC can be be damaged.

BTW: 'and just to make sure I was doing it right to see what kind of reading I would get on AC, I tried it and got 360 on AC on both caps.' You need to check in DC not AC.
So far we have backlights but no pictures on the screen so we need to find out for sure if we have DC on both ends of the SMD fuse on the T-CON board or not.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

The 100K resistor is the part of the RCD snubber circuit for the STBY power supply, so measure that resistor off the board, it is very rare to have bad snubber resistor and if it is open the the STBY will not work properly and SMPS IC can be be damaged.

BTW: 'and just to make sure I was doing it right to see what kind of reading I would get on AC, I tried it and got 360 on AC on both caps.' You need to check in DC not AC.
So far we have backlights but no pictures on the screen so we need to find out for sure if we have DC on both ends of the SMD fuse on the T-CON board or not.

Ok, as for the T-con, I tested DC volts and do not have a reading weather the TV is off or on. I reversed the probes and nothing still. The way I checked it was by putting a probe on each gold metal end of the fuse (The fuse that you circled in red on the picture I posted).

I will soon check the resistance of the snubber resistor and post the results.

I will hold off in ordering parts so I can do it in one shot (order all at once) in case we discover other needed parts unless you say otherwise.

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

"Ok, as for the T-con, I tested DC volts and do not have a reading weather the TV is off or on. I reversed the probes and nothing still. The way I checked it was by putting a probe on each gold metal end of the fuse (The fuse that you circled in red on the picture I posted)."

Black probe of the meter on the chassis then RED probe to test each end of the fuse when TV is ON.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

The 100K resistor is the part of the RCD snubber circuit for the STBY power supply, so measure that resistor off the board, it is very rare to have bad snubber resistor and if it is open the the STBY will not work properly and SMPS IC can be be damaged.

BTW: 'and just to make sure I was doing it right to see what kind of reading I would get on AC, I tried it and got 360 on AC on both caps.' You need to check in DC not AC.
So far we have backlights but no pictures on the screen so we need to find out for sure if we have DC on both ends of the SMD fuse on the T-CON board or not.

OK another reading is .......both cap (C821 and C820) are at 163.7 DC with the TV plugged in but not "ON".

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

And you get close to 400VDC when TV is on?
Also read post 43.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

There you have the result ........I think its stuck open

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

"Ok, as for the T-con, I tested DC volts and do not have a reading weather the TV is off or on. I reversed the probes and nothing still. The way I checked it was by putting a probe on each gold metal end of the fuse (The fuse that you circled in red on the picture I posted)."

Black probe of the meter on the chassis then RED probe to test each end of the fuse when TV is ON.

Im going to redo it .......did not do it that way .....sorry and thanks for clearing it up

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

"Ok, as for the T-con, I tested DC volts and do not have a reading weather the TV is off or on. I reversed the probes and nothing still. The way I checked it was by putting a probe on each gold metal end of the fuse (The fuse that you circled in red on the picture I posted)."

Black probe of the meter on the chassis then RED probe to test each end of the fuse when TV is ON.

What a difference when you do it right .......Thank for the clear instructions, it made all the difference........drum roll please........12v DC on both gold sides.
Blk probe on chassis and each gold side gives me 12v DC.

I hope this works because my wife is having a good laugh.........I cant wait to see her face once she sees a picture on the screen........

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

OK, at least we found the Voltage on the T-CON without getting close to 100 posts like thi one: https://www.badcaps.net/forum/showth...018#post653018
I will need to find good clear pictures of the T-CON board to look for Voltage test points next.
BTW: No one else work on this TV before, right? The cables between the T-CON and the LCD panel were not disturbed, right?
And just to be sure, you do have backlights if you look at the back of the chassis you can see glowing lights through the holes of the LCD panel, right?

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

OK, at least we found the Voltage on the T-CON without getting close to 100 posts like thi one: https://www.badcaps.net/forum/showth...018#post653018
I will need to find good clear pictures of the T-CON board to look for Voltage test points next.
BTW: No one else work on this TV before, right? The cables between the T-CON and the LCD panel were not disturbed, right?
And just to be sure, you do have backlights if you look at the back of the chassis you can see glowing lights through the holes of the LCD panel, right?

You got it.......The TV was bought brand new and NEVER worked on or open until now. I touch and remove some things in order to work on it and take pictures but that is the extent of it.

I ll post the picture as soon as possible.....thx

Yes the backlight work perfect ......screen changes a little in the front but very evident when standing in the back of the TV with cover off.

Thx again

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Ok here are the pictures of the T-Con. Picture 001 is the front and 002 the back of the T-Con I purchased off the net thinking it would fix my issue. Guess what ......it didn't. Pictures 003 and 004 is front and back of the original that is back in the TV right now. Both T-con's fuses were tested and they both give out 12 v.

Hope this helps.....

Thanks for everyones patience.

[CapLeaker]

Re: Toshiba 55ZV650U REGZA sound but no picture

Did you check the LVDS with an oscilloscope yet, in order to figure out if you actually get LVDS signals from the main board to the Tcon?

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

OK, lets test DCV at those eight test points I marked on the board. Black probe on the chassis.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

Did you check the LVDS with an oscilloscope yet, in order to figure out if you actually get LVDS signals from the main board to the Tcon?

CapLeaker that was purely chinese to me ........I really have no idea what your saying. Please help me out........tell me what to do and I ll post the results.

Thanks .......sorry but I am far from being a pro..

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

OK, lets test DCV at those eight test points I marked on the board. Black probe on the chassis.

1 - 0
2 - 1.8 on the chip 0 on the board...it does not have a leg connecting chip to board.

3 - 3.3
4 - 3.3
5 and 6 - 0 if your are referring to the white dot that you circled on the board.
7 - 16.3
8 - 12

all done DCV with blk on chassis
just hope Im touching the right place with the red probe .......the one I m not sure of is # 2, 5 and 6

[Malachi]

Re: Toshiba 55ZV650U REGZA sound but no picture

5 and 6, the copper circles.

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

I redid the test .......

number #5 I get 26.9 v
number #6 and I get -7........did it 3 - 4 times blk on chassis red on dot.....I finally saw real small dot

[eztiger12]

Re: Toshiba 55ZV650U REGZA sound but no picture

5 and 6, the copper circles.

Yup I finally saw it with a flash light and magnified glass.

Thanks Malachi

[budm]

Re: Toshiba 55ZV650U REGZA sound but no picture

Well the Voltages seem to be present.
So as capleaker suggested, now you need an Oscilloscope to see if the signals from the main board are being fed to the T-CON or not.

[Joseph cauchi]

Re: Toshiba 55ZV650U REGZA sound but no picture

Becareful when you check the filter caps because these are at the hot side of the PSU.Check with your multimeter on DC black to - and red to+