TCL LE48FHDF3300Z - No Picture

[AtomicPunk]

Picked up a TCL LE48FHDF3300Z - when plugging in I see the power light on the front come on. When turning on the power either with remote or power button, the light goes out - don't see anything on the screen.

I've also tried disconnecting the left - then the right t-con connector - again, power light will come on; then when pressing power button the light goes off - nothing appears on the screen.

Model: LE48FHDF3300Z
Power board: 40-E461C4-PWI1XG PE461C4
Sub power: 40-RL5510-DRE1XG
t-con : SQ60PB_MB34C4LV0.1
Main board: 40-RSC803-MAD2HG

[budm]

Re: TCL LE48FHDF3300Z - No Picture

Are the backlights on or even come on for seconds?
What kind of Voltage measurement have you done so far?

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

Thanks for the reply!

I have not seen anything from the back lights. Was hoping there would some service manuals that would give me specific locations to check voltages.

I haven't attempted any voltage checks - the front of the PCB do not have many indicators of where to check voltages.

I've attached some updated photos from the back side - assume that's my best location to check as there are some markings - still need to do more research to figure out what some of these mean.

I'll review your links - but appreciate any recommendations on where to start checking voltages (power board first?)

[Andrew F. Ali]

Re: TCL LE48FHDF3300Z - No Picture

From my previous experience with TCL TVs, I've found that their LED Drivers go bad after 2-3 yrs. Do you have LED Backlight Tester?

[nomoresonys]

Re: TCL LE48FHDF3300Z - No Picture

Thanks for the reply!

I have not seen anything from the back lights. Was hoping there would some service manuals that would give me specific locations to check voltages.

I haven't attempted any voltage checks - the front of the PCB do not have many indicators of where to check voltages.

I've attached some updated photos from the back side - assume that's my best location to check as there are some markings - still need to do more research to figure out what some of these mean.

I'll review your links - but appreciate any recommendations on where to start checking voltages (power board first?)

Yes that's usually the best place to start, test connector from mainboard to powerboard on powerboard side, sholud be a little legend/map of expected voltages, test with tv plugged in but off then hit power, report both conditions here, give pin number, pin description and condition on and off, demonstration in signature below.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

Voltage Checks - all on the main power board

From power board to sub-power
pin - label - "off" - "on"
1 - A_DIM - .1 - .2
2 - P_ON - .1 - .2
3 - BL_ON - .1 - .2
4 - PT - 0 - 0
5 - GND
6 - GND
7 - GND
8 - GND
9 - GND
10 - 24V - .2 - 24.4
11 - 58V - .2 - 55.3
12 - 58V - .2 - 55.3
13 - 58V - .2 - 55.3
14 - 58V - .2 - 55.3

From main power to logic board
Pin - Label - "off" - "on"
1 - 24V - 0 - 24.4
2 - 24V - 0 - 24.4
3 - GND
4 - 24V - 0 - 24.4
5 - GND
6 - GND
7 - 3.3VSD - 0 - 0
8 - A_DIM - 0 - .1
9 - GND
10 - P_ON - 0 - around 2.5
11 - P_DIM - 0 - .2
12 - BL_ON - 0 - .2

[Unspun01]

Re: TCL LE48FHDF3300Z - No Picture

Shine a flashlight at screen or view in bright sunlight when you turn the TV on. If you cannot make out a faint image on the screen then your issue may not be backlight issue (since entire TV is dead). If your power LED goes out completely, and if you do not have any sound from any connected source it may be SPIFLASH/EEPROM issue.

Try heating or freezing the 8-pin EEPROM IC on the mainboard near the marking "40-RSC803-MAD2HG" where the LVDS cable plugs in.

I repaired a similar mainboard by extracting contents of existing IC, reprogramming a new IC and installing on the mainboard.

Report back with any changes sue to heating or freezing the IC.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

The power light goes out as soon as I press the power button, tried using dust off to cool the eeprom, but didn’t see any change. I do not see any backlight flicker or picture or have any sound.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

Also when I was checking P-on before the 2.5v wasn’t constant.
Sound the 3.3vsd be constant? I got no reading when the tv was off or on.

[nomoresonys]

Re: TCL LE48FHDF3300Z - No Picture

Try unplug tv from outlet, unhook powerboard from mainboard connector, plug tv back in outlet turn tv on see if backlights come on.

[budm]

Re: TCL LE48FHDF3300Z - No Picture

Are you 100% sure that you do not have the 3.3VSB Standby Voltage? It does not make sense for you to still have power LED lights and the PS-ON control signal if there is no 3.3V standby Voltage to run the main board.
Can we also see the pictures of the whole back side of the TV showing how all the boards are connected together?
This looks to be your power supply board: https://www.shopjimmy.com/tcl-08-pe4...pply-unit.htm#
TCL 08-PE461C4-PW200AA (40-E461C4-PWH1XG) Power Supply Unit.
Pictures provided by shopjimmy.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

When I opened up the back further while disconnecting the logic board it started working - i hadn't seen the backlights working before. I reassembled the TV. However, once it is on, if I hit the power button; I can't get the TV back on.

I believe the sequence to get it back running is that I must leave it unplugged to 1 minute; then plug it in; wait 10 seconds then hit the power.

I am not 100% certain on the 3.3VSB - as i might have not had good connection.

I've attached a photo of it working - so panel and back lights all look good.

As always appreciate the responses and suggestions.

[budm]

Re: TCL LE48FHDF3300Z - No Picture

More likely the 3.3VBS is OK, you were missing bl-on and Dimming control signals when backlights are not on.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

Any suggestions, thoughts on why I have to follow this sequence to get it back on - and/or if i should just replace the main power supply board?

[budm]

Re: TCL LE48FHDF3300Z - No Picture

It may be EEPROM issue.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

I went into the service menu - cleared NVM then hit FAC HOTKEY - I think that inadvertently turned on fast startup - so I can no longer get the unit to power on. Not good. Unfortunately I don't see any logic boards available that are of the same model (and reasonably priced) - 40-RSC803-MAD2HG

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

Before when plugging in the TV - then unplugging it for 1 minute; then plugging it back in after 30 seconds; I could get it to power up and run.

I went into the service menu - I turned on Factory Mode hotkey - which I thought was a reset of the NVM - but according to the manual just allows you to go into the service menu without having to go thru the extra steps.
Also I believe that Warm-up got turned on - but then also I did a NVM reset - the tv turned off - and I could never get the power light to illuminate again.

I did find a service manual where the TV looks very similar to this the one I have (although not exact) "FVM4012 RSC8L service manual" which has Sanyo on some of the pages and TCL references on others.

The power light no longer illumines after plugging in the TV - no backlight - did notice that all of the pins that did have 58v are now only showing 55v.

[nomoresonys]

Re: TCL LE48FHDF3300Z - No Picture

Sounds like you might have gotten a setting messed up in service menu, see if this applies to your tv: Using a straightened paper clip or ball-point pen, press and hold the recessed RESET button on the TV connector panel.
Continue to hold the RESET button for approximately 12 seconds.When the reset cycle completes, the status indicator comes on dim.
Release the RESET button. The TV is now powered off.
Turn on the TV and proceed through Guided Setup.

[nomoresonys]

Re: TCL LE48FHDF3300Z - No Picture

If you get it back to "half working" again try a firmware update/reapply, does seem like a mainboard issue.

[AtomicPunk]

Re: TCL LE48FHDF3300Z - No Picture

I was unable to locate any sort of reset button. However, tried holding down various buttons while plugging in - and I was able to get it back up and running. Unfortunately I have been unable to locate any firmware to update it with.

But still must go thru a specific sequence in order to get the tv to start up, i'll get a picture of the service menu tomorrow.