Toshiba 32BV500B suspected panel fault

[notallbad]

Would everyone here tend to agree?

PS - 17PW26-4
MAIN - 17MB45M-3
PANEL - LTA320AP06
INVERTER - SSI320-4UA01
TCON - 320APO7S4LV0. (can't quite see the ver. no.)

PS b/d voltages in stby and powered on check out ok.

Odd behaviour - no led status on the front panel in either stby or when switched on, in stby the TV still beeps when the front buttons are pressed i.e vol and channel up/down buttons, also insert a USB drive and the TV shuts down. Otherwise operates as normal.
Picture is the main issue, see attached photos. It doesnt show like this immediately after switch on, it slowly 'bleeds' down the screen, eventually the whole screen whitens.

Remove the T-con cable and just shows a backlight blueish/black screen with no distortion, kind of expected I guess. Just for added info.

Menu shows fine.
Input source (HDMI) shows fine.

Photo of PS b/d voltages also added.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

OK, so there is a front panel LED, in stby it is lit white very dimly, when the tv is on it goes out.

Obviously not an on/stby light! Perhaps for fault diagnosis but its not flashing in this TV.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

There are 2 LD1117AL regs on the main bd.

In 7.89v, out 1.2v relative to gnd pin

In 2.56v, out 1.2v relative to gnd pin

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

On the T-con bd 320AP07S4LV0.4 theres an A1718.
2SA1718 PNP Power transistor.

With power applied volts read, relative to gnd point:
Base 13.9v
Collector 0v
Emitter 14.29

[dskall]

Re: Toshiba 32BV500B suspected panel fault

Just my opinion but doesn't seem like a panel problem

[Davi.p]

Re: Toshiba 32BV500B suspected panel fault

Hi, it is a very common problem with Samsung panels, i would like to ask you if you can measure esr or ripple out the power bd on 12v line. Second test, disconnect one at a time the ribbon connec. between tcon-panel and take a picture of the result, please scale pictures when is possible that slows down page.. Third try, locate CPV1, CPV2 testpoints on tcon and with continuity see to which pin goes on the connector, then put a small stripe of tape on that single contact on the ribbon, in turn first CPV1, second CPV2, then if there are significant changes post them here.. Bye

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

Took soom readings from the 'T-con' bd.

All relative to the T-con gnd point.

VCNT 6.95v
VCOMS1 6.14v
VCOMG1 6.14v
VCST1 6.14v
VCOMS2 6.14v
AVDD 13.9v
DVDD 3.0v
VON 25.7v
VOFFE -11.12v
IN 11.51v
VIN 11.51v
SCL_II 0.6v
SDA_II 0.69v
VDDT 3.08v
RVDD_DIG2 3.08v
RST 3.01v
TCON_RDY 3.07v
VDDOP_RSDS 3.08v
SDA 3.07v
SCL 3.07v
WPP 3.08v
EVDD 3.08v
VCOMS3 6.15v
REV 1.57v
TP 0.16v
CKV2 7.32v
CKVB1 7.36v
CKV1 7.3v
TMP_FB2 1.83v
VCST2 6.13v
VCOMG2 6.15v
VCOMS4 6.15v
CVO 8.32v
VR 8.44v

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

Hi, it is a very common problem with Samsung panels, i would like to ask you if you can measure esr or ripple out the power bd on 12v line. Second test, disconnect one at a time the ribbon connec. between tcon-panel and take a picture of the result, please scale pictures when is possible that slows down page.. Third try, locate CPV1, CPV2 testpoints on tcon and with continuity see to which pin goes on the connector, then put a small stripe of tape on that single contact on the ribbon, in turn first CPV1, second CPV2, then if there are significant changes post them here.. Bye

thanks for reply.
1) unfortunately I do not have a working scope

2) the ribbon cables to the 't-con- bd are heat bonded on at both ends

3) CPV1 & 2 must be named something else on this board, please see post above with 't-con' test point volt readings

The T-con bd is not the usual type that usually sits between the main bd and the panel bd, it is the panel bd or perhaps video processed /scaled etc on the main bd which is more likely.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

USB problem resolved. Well wasn't a fault.
Plugged in an external hdd thats usb3.0, power draw must have been too large as the TV's usb port is 500mA max.

Plugged in a 2gb USB stick (needs to be formatted fat/fat32, I think) and plays films perfectly fine.

Well at least thats one less issue. User error fortunately.

Still just leaves the main issue of panel distortion.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

For info.

[dick_barton]

Re: Toshiba 32BV500B suspected panel fault

I wonder if you have a mainboard fault. The menu details all look fine and no characters are missing.

[Davi.p]

Re: Toshiba 32BV500B suspected panel fault

"unfortunately I do not have a working scope" I have never spoke about scope, it is not necessary.
"it is the panel bd or perhaps video processed /scaled etc on the main bd which is more likely." I dont understand this sentence, sorry, you are meaning that the tcon is integrated to the panel, so is large as the panel and deep few cm?
CPV1,2 in your tcon is CKV1,2 , have you understood my suggestions? I have never done this test and i can't do now because i have damaged the only one tv that i own with this sympthom. Sorry, but there's no risk.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

"unfortunately I do not have a working scope" I have never spoke about scope, it is not necessary.
"it is the panel bd or perhaps video processed /scaled etc on the main bd which is more likely." I dont understand this sentence, sorry, you are meaning that the tcon is integrated to the panel, so is large as the panel and deep few cm?
CPV1,2 in your tcon is CKV1,2 , have you understood my suggestions? I have never done this test and i can't do now because i have damaged the only one tv that i own with this sympthom. Sorry, but there's no risk.

Sorry, misunderstood.

1) If correct, DMM on ac setting, probes across chassis ground and +12v. Reading is 25.5v ac.

2) There is no T-con bd! Its either integrated on the main bd or it is the board that is heat bonded onto the top of the lcd panel. If I remove the bonded connectors there is no way I would be able to rebond them back on.

3) I do understand your suggestion and shall try it when I have more time on my hands - the panel has been re-assembled due to lack of working space, little children and inquisitive hands.

Thanks again for your help, appreciate it!

[Davi.p]

Re: Toshiba 32BV500B suspected panel fault

1) I have never asked you to measure any voltages, only ESR or ... ehm sorry, yes i've asked for a view of the ripple, but you don't have scope, so an esr meter?
2) ok, since i recognize tcon marking, it is a Samsung, mainb. is Vestel, so tcon is integrated in the panel..
Bye..

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

Yes, have an ESR-2501A ESR METER, cheapo meter compared to most others.

[vinceroger69]

Re: Toshiba 32BV500B suspected panel fault

This seems like a common issue on this model
https://www.badcaps.net/forum/showth...shiba+32BV500B
out of curiosity its the lcd/tcon pcb on the top or bottom of the tv, there was a thread a while ago where the tab bonds was on the bottom of the lcd panel and someone had cleaned the screen with liquid which had then ran down onto the board and caused corrosion etc just though i would mention it.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

Located on the top. Have inspected the board and looks ok.

Anyone know if the tcon can be powered independently?Though I suppose it would need more than just the 12v and gnd feeds.

[vinceroger69]

Re: Toshiba 32BV500B suspected panel fault

thats handy too know for future reference thanks.

[notallbad]

Re: Toshiba 32BV500B suspected panel fault

Yes it would seem my symptoms are the same as the thread you posted above. Might be best just to ditch the panel.
thanks vince

[vinceroger69]

Re: Toshiba 32BV500B suspected panel fault

Its a pity in the other thread was not updated to see if they found the problem or not, but the other thread does look like exactly the same issue.