LG 32LV5500 CH:LT12E goes on but no image, BL or sound

[budm]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

BTW, output of one circuit can feed many circuits, just have to spend time looking at many many pages of the schematic to see how output of one circuit feeds other circuits, it is very time consuming.
It is especially bad when the schematic does not show the signal linking path from one page to another pages.

[budm]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

BTW, If look at some of the notes in the diagram PDF page 52, this model can be fitted with LCD panel from LG, CMO, AUOPTO, and SHARP. That is why there are so many options shown in the schematic.

[yoritomo]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

I did some checking about it now, and pin 10 and 11 of micom are in state 1 , the circuit is working correctly, when following the schema it means :
Back light OFF
Panel OFF

This means Micom is not asking the display to work for some reasons, perhaps a init test error ?

I checked ram power which is ok too with 1.51v

The thing I don't understand, why Micom enables the power supply to start but not the panel ?

[budm]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

'This means Micom is not asking the display to work for some reasons, perhaps a init test error ?' may be, that is why now it needs really in-depth troubleshooting, firmware corrupt? bad EEPROM? who knows.

[yoritomo]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

humm it is turning in a bad way then i don't have any eeprom programmer and no experience in such fix, easy when menus are available, but in this case we are on the manual procedure. May be the time i should give up, but so exiting challenge to learn anyway.

Anyway i could not find any dump for this model.

[dick_barton]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

Can you try a firmware update
http://www.lg.com/pa_en/support/supp...ct/lg-32LV5500

[yoritomo]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

I downloaded the firmware, and i followed update notice provided with it, i am trying in blind and does not looks like any changes, the problem is that i can't see any progress of course.

As i could read i plugged the usb stick with the folder LG_DTV containing the unzipped dump. when the tv was on i inserted the usb stick, i clicked ok (blindly) to try to accept (start) on the upgrade window. i was waiting a while to be sure, but i could no see any reboot from the tv, then i tryed again but this time using the RC left arrow in case the default option would be cancel, no more results ...

Now i am out of ideas

Thank you all of you for your experienced help and ideas.

EDIT: i used firstly the USB port called "USB 1 App" i presume this is the technical port.

[yoritomo]

[solved]LG 32LV5500 CH:LT12E goes on but no image, BL or sound

DONE!!!!!

It was a RAM issue, it was acting such a laptop with dead ram, going on but no sound or images or logo ... then when i see it on a laptop i always check the ram first it is often coming from there, i did the same with this TV.

Then i disassembled the big heat sink of the main board, i reflowed the pair of ram chips and now the tv is working fine, yes i know a reflow is just a test, now i am going to reball them carefully.

Thank you all for your great help again, i always progress in troubleshooting following your clues.

Can some one rename the topic as solved please ?.

[fghisleni]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

Dear gentlemen, good evening everyone.

I had a similar problem with my TV LG 32LV5500. When you turn it, it just did not have video or audio or BL. Anything.
I read carefully all the comments but read the service manual. After many hours thinking about the problem I decided to remove the heat sink from the processor. It was the only thing he had not done. Then, with the heatsink removed I checked the conditions of the processor and flash memory.

In a desperate measure, I decided to heat the processor with hot air hoping to put be some cold solder. Then, with the hair dryer of my wife, I directed hot air over the processor for a few seconds.

After reassembling the sink and the board, the TV again function normally.
I appreciate the space and congratulate the excellent forum.

FGhisleni

[sansgp]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

Dear Friends,

I would like to Share with you my repair experience on LG-LED LCD TV model 47LW5700-TA. Problem with this tv was, when I was watching the TV program, it just turned off. When I press power ON again, TV has no display & no sound. though the TV as a unit has power, which I determined from the Power ON LED. It cycles from dark to red in slow motion every 2 seconds or so.

I always supported the TV Designers (LG, Samsung, Sony, Philips or anyone) and I am sure, no one designs their circuits to fail exactly after the product warranty period is over! but alas, here the unreliable partner is the manufacturing process, which actually helps to put together electronic devices on a PCB. (be it BGA, SMD, Soldering, manual process etc).

With this in mind, I tried various ways to solve this issue. And to cut my story short, the real reason for the fault is due to the digital circuits, not making communications within the Mother board. Therefore, we are seeing the power LED cycles from dark to red in slow motion, an indication that some link is missing.

Solution: Use the hot air blower on digital ICs, which may have poor solder / joint connections (smd/bga chips with tiny pins bound to have this problems from time to time)! I set the temperature to around 320 degrees and slowly moved it on to RAMs, processors, EEPROMs, NVRAMs (one needs to ensure these chips dont get burnt...of course) so as to improve their leads connections on to the PCB tracks. Let the chips cool down (5 to 10 mins). Then, turn ON the tv... it worked for me, finally...

Simplified operation of the TV:
when you hit the power ON switch, the main board should send
the PS_ON (>2.5VDC, this signal is used to turn on the switched transistor to
supply the VCC which is generated by the AUX winding of th STBY transformer to run the PFC controller IC and the SMPS IC) to turn on the PFC Voltage booster (the voltage on the cap should go up from 160VDC to >360DVC) and the 12V/24V SMPS section. after slight delay, it should send the BL_ON and diming control signals that are routed through the power supply to the inverter board to turn on the backlights, and at the same time the processor on the main board will send the T-CON ON command, to turn on the MOSFET, to supply the 12V to the T-CON board. This is the
basic POWER ON cycle operation of the TV.

Hope this will help someone in their understanding of the fault better and repairing.

[vasvir]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

LG TV 37LV5500 here...

This also fixed it for me. With a hot air gun I hit the central cpu for some seconds after I had masked everything else with aluminum foil.

The problem is that now again does not work (after a week). So a proper reballing is the solution.

Two questions for the forum:

1) The main board is EAX64104702(1). Looking for a replacement I see the same board for different models and sizes. See example here http://www.yoycart.com/Product/37718355989/ or http://www.lcd-plasma-parts.co.uk/EA...-LG-MAIN-BOARD or https://www.aliexpress.com/store/pro...689147717.html

The question is: Is it possible to have another EAX64104702(1) for 42, 47, 55 and another for my 37''?

2) When I removed the black metallic plate in order to reveal the processor I noticed a (sort of) plastic substance sticked to the metallic plate like dried glue. I would assume that some thermo conductive pasta conductive material should be there like the one we put between cpu and the heatsink. Does anybody know what is this material? Is it thermo conductive? Since this is the second board and a repeated problem I am thinking to put some paste and or a custom heatskink (after the reballing).

Any ideas?

Thanks in advance

[vasvir]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

Hm the plot thickens.

Apparently in the first repair 1+1/2 years ago the technician changed my main board with a 42LV5500 one.

Looks like the original for 37'' is EAX64405404 (0) refE2103 (although my TV is 2011) See here http://www.ebay.es/itm/162174689226?rmvSB=true#shpCntId while I have EAX64104702(1) See previous posting...

I am at a loss here...

[Dgtech]

Re: LG 32LV5500 CH:LT12E goes on but no image, BL or sound

.