LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XXX

[thevolatile1]

This model is UK LG 42LE5900 (-za) - basically the same guts or at least same PSU as lots of the XXLE5 series 5500 etc. PSU in this one is EAY60803201 (board is customised for this model i.e.. PCB has jumpers that change the pcb parameters & model number etc for other types of screen (notably AUO screen or LG). For the wannabe hackers out there - this one has the highly hackable Broadcom chip on the main AV board
When working this is a pretty good display that can record to hdd, run on your internet connection view all manner of movies & audio aswell as having freeview HD channels. Not bad when it works..
SO, this ones had an attempted repair done by a rank amateur - on opening it I found some of the metal casing brackets missing - no big deal.. and truly terrible soldering in of a MOSFET & diode..
Its safe to assume that the guy found a repair fix found on this site for a 42LE5500 PSU with the same fault but it didn't work. In any event I replaced these components to eliminate the possibility of it been the problem - the guy hadn't removed the heatsink to fit the mosfet so he'd ended up soldering wires on to reach the mosfet pins.
How it is now - you can power it up & it goes through boot LED sequence on the trim & lights up LG logo, then it goes out. Pressing buttons on remote or the tv itself gets a reaction & you can turn it back off with remote or front buttons but there's no sound & no picture & no backlight. Ive got the service manual for this range of TVs & at first glance at the booting sequence diangram, this one fails around stage 6 - where the power to fire up the audio & screen is turned on.. I'd assume at this point that the 12/24v voltage regulator should kick up to run these circuits and for some reason it doesn't work now. I will get round to metering a few parts at some point but I'm pretty busy & a lot lazy. So, has anyone repaired this fault before ??
Oh yeah, I took macro pics of the replacement parts I installed etc Gimme a shout if you need to see..

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

...boot sequence for PSU

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

boot seq pt 2....

[Alastair E]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

It seems this model can be fitted with Two distinct types of PSU. The ones Ive seen are more commonly fitted to the 42LE4500, and have a larger LED Driver sub-board (That always stuffs up....)

Your PSU is basically pretty similar though, Two stages, One for LED's and the other for the rest of set, both these stages run from the same PFC stage....
--There is a third, that supplies the ever-5V to the mainboard--the Stdby-supply, running from rectified mains.

Is there any supply on the main LED SMPS supplying the green sub-board of the PSU when turned on--even for a second or so?
Is there any supply on the Other--supply SMPS that supplies mainboard and everything else, when turned on --even for a second?--except the ever-5V,--That comes from the rather small dedicated SMPS--which should be present whenever set plugged in?

Ive got one in from the Brother-in-law, This one's dead with a blown fuse After the PFC stage.
Two MOSFETS that drive the LED Inverter SMPS are short and a small hole in the controller-chip--I was expecting spares in the mail today--but none arrived....
--These PSU's are CRAP--especially the LED Driver sub-boards!

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

Yup, crap psu.. to be honest I think all LG, samsung sets are all crap once you get the back off, but hey, thats life - bring back plasma !!!! Anyways, had a chance to look at this some more.. Main power circuits seem ok & I'm getting the 3.5v 12v & 20v at the output socket. NOT getting anything on the INV_CTL pin though, which should be 3.x volts. Tracing at the socket on the main AV board & all the resistors are ok (r8019, r8026, r8032) q8005 is the tiny transistor & I couldn't get a proper reading there so I pulled it & replaced it with a BC848 (2SC3052) NPN.. Still no joy & still no signal there.. Kinda getting to that stage of 'going in circles' now and it doesn't help that somebody else has had a go at it as I dont know if the sound portion is actually working. I do believe that the whole thing is down though

[Alastair E]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

So--Your Ever-5V is OK and so is your 'everything else bar LED's supply' is OK....

Seems its just your LED supply thats out then.

IF you check the board, you'll see which of the two larger transformers supplies the 'everything else' supply and the one that supplies the 82V for the LED Controller.
--There'll be a rec and a pair/single electrolytic 22uF 150V--Monitor the voltage across this...

IF it goes up to 72V, just for a second--then to 0, you probably have a duff LED Control-board--That green S.M. turd on the PSU....

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

STBY Voltage is 3.5v on this one.. I'm thinking of the shortcut method to try the backlight (as described in the service manual).. power supply output.. INV_CTL pin 18 shorted to STBY 3.5v pin 9,10,11 or 12 - this should force the screen into life for testing,,, my only concern is that it causes other damage ?! Test meter battery is dying now so readings are sketchy

[Alastair E]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

If it says in the service-manual then it shouldn't cause damage....

[budm]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

To test the backlights you will need to force on the main power supply section and then force on the backlights circuit section.
I would use two resistors (500~1K) (to limit the current in case you accidentally short the 3.3VSTBY wires to the chassis) between the PS-ON and 3.3V, INV_CTL and 3.3V. You need to remove those two signal wires going back to the main board first before forcing on.

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

Well, this has turned into a strange one... Fault has now changed & maybe Ill have another chance to look again over the next few days..
As it stands now - I turn the tv on & after about 20 minutes it springs into life & works perfectly. It may continue to work fine or it will lose image again after half an hour or so.
I did find out that after this tv was previously 'repaired' it only lasted a month before failing again (mosfet & diode were changed). I kinda assumed on seeing the childish soldering job that perhaps the psu board had been mishandled & caused a broken joint on the board so I gave it a blast with the old heatgun & then traced & resoldered all the main circuit for the backlights. My next port of call is going to be a firmware update. I will post again once Ive had another go at it. Oh & I didnt see the note about resistors budm but I followed the info on the service manual & the backlights fired straight up for the test.. Im not gonna really waste much more time on this tv as Im really busy with work at the moment & I can get a replacement psu for £25 but checking the firmware seems a good idea as Ive seen a Toshiba tv with a similar fault cured with a firmware update.

[thevolatile1]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

This one's now sorted.
So, it's had a mosfet & diode.
Took IC9000 chip out (Winbond IC back of main av board) & reflashed it with an spi programmer.
TV fired straight up at this point & I put latest firmware update on using a USB stick.
I have the winbond flash & update files if anybody wants them

[loadedboyuk]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

hi, i have the same fault, found a dieod shorted out, but can you tell me which mosfet you had an issue with save me testing / lifting them out?

\Thanks

[loadedboyuk]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

bump?

[Gaffers11]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

Hi Everyone,

I think I'm in the same situation as Volatile1. I'm wondering if one of you smart chaps could please tell me how to go about reflashing that IC9000 chip? A point in the right direction and I should be able to figure it out - I'm just a bit stuck currently!

Thanks,

James

[RGSX750]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

This one's now sorted.
So, it's had a mosfet & diode.
Took IC9000 chip out (Winbond IC back of main av board) & reflashed it with an spi programmer.
TV fired straight up at this point & I put latest firmware update on using a USB stick.
I have the winbond flash & update files if anybody wants them

Hello.
i need the file for the IC9000 (if you still have it) so i can give it a try

[Liorsi]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

Hi,

I have the same problem. Could you please send me update files and winbond flash?

[pmac]

Re: LG 42LE5900 Responds to remote NO Picture or Sound EAY60803201 LE5 Series 42LE5XX

hi,

could you tell me, if you remember of course, which diodes and mosfets were the faulty ones to save me time lugging the pcb to the uni workshop?