Acoustic solutions LCD26761HDF no backlight

[sienoki]

This set will display an image under flashlight..its got 17PW26-1-V3 psu...17MB35-1 mainboard...VIT70063.50-REV3 inverter board.

When arial in will only display no signal so not sure on sound..there is no bloated caps..several HEC..SAMXON..CHANG caps on psu.
Ive tested fuse on psu that tested good..no power going to inverter from checking the 4 red wires as i get no readings

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

The 24vdc to the Inverter will not be there until the PS_ON (ABOUT 3.3~5VDC) is supplied by the main board is sent to the power supply to turn on the 24vdc and 12vdc power supply to turn on.
I wrote up a basic guide here:
http://www.fixya.com/support/r509388...shooting_guide

I aalos post a lot of pictures here:
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

The 24vdc to the Inverter will not be there until the PS_ON (ABOUT 3.3~5VDC) is supplied by the main board is sent to the power supply to turn on the 24vdc and 12vdc power supply to turn on.
I wrote up a basic guide here:
http://www.fixya.com/support/r509388...shooting_guide

I aalos post a lot of pictures here:
Failed TV and Monitors pictures: http://s807.photobucket.com/albums/yy352/budm

What should i be checking next..thx

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

What should i be checking next..thx

Readings from mb pin with multimeter on 20v setting & tv switched on
1.0.00
2.8.18
3.2.88
4.0.00
5.0.45
6.0.13
7.5.09
8.3.37
9.0.51
10.0.51
11.0.51
12.0.16
13.0.05

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Readings from mb pin with multimeter on 20v setting & tv switched on
1.0.00
2.8.18
3.2.88
4.0.00
5.0.45
6.0.13
7.5.09
8.3.37
9.0.51
10.0.51
11.0.51
12.0.16
13.0.05

can any 1 suggest my next step in trouble shooting this set plz..thx

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

Check the diode for the 24V output.

Any audio?

This supply might power the main board 5V and 3.3V directly from the standby supply and the inverter from the main supply only.

Looks reasonably decent for a Vestel aside from the caps... rare sight.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Check the diode for the 24V output.

Any audio?

This supply might power the main board 5V and 3.3V directly from the standby supply and the inverter from the main supply only.

Looks reasonably decent for a Vestel aside from the caps... rare sight.

Which diode do i test tom..a good diode will have a reading 1 way & OL the other way right?
Theres dosnt seem to be any audio with tv areil in just says no signal..will get back on to this set when finished decorating house..
Should i desolder 1 leg of the diodes for a good reading..thx

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

Which diode do i test tom..a good diode will have a reading 1 way & OL the other way right?
Theres dosnt seem to be any audio with tv areil in just says no signal..will get back on to this set when finished decorating house..
Should i desolder 1 leg of the diodes for a good reading..thx

The three legged device on the heatsink near the 24V connector is the device I am referring to.

Fingers work as good antennas sometimes... at least where I am because we are fairly close to Hannington TX.

I'm asking about the audio because I recall some Vestel sets used 24V to power the audio too so if this is missing you will get no inverter and no audio.

No need to remove the device unless results are inconclusive.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

The three legged device on the heatsink near the 24V connector is the device I am referring to.

Fingers work as good antennas sometimes... at least where I am because we are fairly close to Hannington TX.

I'm asking about the audio because I recall some Vestel sets used 24V to power the audio too so if this is missing you will get no inverter and no audio.

No need to remove the device unless results are inconclusive.

The diode Q827 connected to heatsink closest to the inverter plug on psu is a STPS20S100CFP-7PAAF-VW is this the diode a power schottky rectifier?
if so the readings are R-red..B-black measured with fluke77 series II
B1-R2=1.069
R1-B2=.261
B2-R3=.261
R2-B3=1.069
Theres another 1 on another heatsink same part no schottky which measures
same B-R as above with readings of
.570
.250
.249
.555
do these readings appear correct?

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

Is it definitely a "Q"? Might be a MOSFET then not a schottky. More difficult to test. You will need to remove it first to test it.

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Are there any labeling on the white pin to the right of the power supply board? The one on the top left is for the 24vdc, dimm, and Backlight_ON connectionS which goes to the inverter board.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Are there any labeling on the white pin to the right of the power supply board? The one on the top left is for the 24vdc, dimm, and Backlight_ON connectionS which goes to the inverter board.

All the mosfetts or schottky attached the the heatsinks are marked Q with no on psu...the white pin out PL816 has no labelling or markings any where on psu for output voltages

[tom66]

Re: Acoustic solutions LCD26761HDF no backlight

The STPS20S100CFP is a power schottky, see here: https://cdn.badcaps-static.com/pdfs/...b186bda3b6.pdf

Post a picture of the underside of the board.

It is probably 24V.

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

One of those pin on the White connector with double-row pin on the right side of the P.S. board will be for PS_ON signal input from the main board, but since the board is not labeled, it will be hard to trace out the connections.
The red wires on the balck connector on the left side of the board will be the 24vdc out put.
I agree with Tom66, the good clear pictures of the bottom side of the board may help us tracing out the connections.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

One of those pin on the White connector with double-row pin on the right side of the P.S. board will be for PS_ON signal input from the main board, but since the board is not labeled, it will be hard to trace out the connections.
The red wires on the balck connector on the left side of the board will be the 24vdc out put.
I agree with Tom66, the good clear pictures of the bottom side of the board may help us tracing out the connections.

Desoldered that schottky readings are same sequence as 1st test
just stays on .OL
1 beep .279
1 beep .279
just stays on .OL

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

The first two pictures are really out off focus, I can hardly trace out the traces from the black connector to the surface mounted components.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

The first two pictures are really out off focus, I can hardly trace out the traces from the black connector to the surface mounted components.

I,ll have to borrow a decent camera as mine is s..t

[budm]

Re: Acoustic solutions LCD26761HDF no backlight

Please make sure to put the camera in MACRO mode for good close up pictures.

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

Please make sure to put the camera in MACRO mode for good close up pictures.

From the underside the 1st smd from the black connector is D861 a small black diode im presuming?this reads 806 one way & 198 the other..if this is a diode im guessing this is faulty right?..ive tested the other small smd black diodes & readings 1 way & stays on 1 the other..thx
Tested that diode with my fluke as i tested it prior with my cheapy multimeter..readings from .OL it gives 1 beep & .208 the reverse .722
The only markings on that D861 is AP..thx

Ive found this while googling does it help till i can chase a decent camera thx..it was in another tv forum & said it was same layout..thx

[sienoki]

Re: Acoustic solutions LCD26761HDF no backlight

From the underside the 1st smd from the black connector is D861 a small black diode im presuming?this reads 806 one way & 198 the other..if this is a diode im guessing this is faulty right?..ive tested the other small smd black diodes & readings 1 way & stays on 1 the other..thx
Tested that diode with my fluke as i tested it prior with my cheapy multimeter..readings from .OL it gives 1 beep & .208 the reverse .722
The only markings on that D861 is AP..thx

Ive found this while googling does it help till i can chase a decent camera thx..it was in another tv forum & said it was same layout..thx

Sorry for measuring white pin out not properly 1-27
1--0v 2--0v
3--0v 4--07.9
5--0v 6--0v
7--0v 8--0v
9--0v 10--0v
11--11.8v 12--11.8v
13--0v 14--05.0v
15--03.2v 16--03.2v
17--05.0v 18--03.3v
19--05.0v 20--03.2v
21--0v 22--03.2v
23--0v 24--0v
25--24.3v 26--24.2v
27--24.3v