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Discussion Starter #1
Today when my girlfriend came home and turned on our tv (LG RE44SZ21RD) she also turned on the AV amp. I think by misfortune they both tried to kick in at exactly the same time and drew too much current for our RCD throwing the trip switch.


I switched the TV to off, then reset the trip switch, then turned the TV back on. The tv came into standby fine (red LED illuminated as usual) and when I used the remote to turn the TV on that seemed to work too... The green LED flashed several times then stayed on. However, I get no picture.


Let me stress: The TV does not turn itself off after a certain time or give a flashing amber LED - ie protection circuit is not activated (so as far as the TV is concerned everything is fine).


The problem is that the lamp is not illuminated at all. I decided to check if the lamp had blown by replacing it with one I know works. (I replaced my old lamp when it got to 6k hours despite the fact it still worked - so I used this for a test).


So I guess the next most likely fault is the ballast board. The one in the TV is an OSRAM board - 3757790027. LG part number 6316000002D.


What I want to ask you guys is... is the ballast likely to be the problem? what is the procedure to test the ballast board?


I am a physics phd student so I have some electronics knowledge and have some lab equipment available to me.
 

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See if you can get a Service manual for it and in there it will give you a ladder for most of the faults and how to test it step by step.

My LG service manual has it and its very handy.

Remember Service manual not User manual, I got mine on Disc and it was cheap here in Australia so give it a go around your way.

I alway encourage people with a Electrical/Electronic background to always buy a service manual on anything you buy as you never know when you will need it.

PS A mate of mine was quoted $1150 to replace a light engine because it kept shutting down, I had a quick look and found a cooling fan was not working (92x92MM) and to make this even worst my mate whilst cleaning it inside before accidentally pulled out the lead for it about a foot away from the fan. so it cost him nothing.

Most LG ballast cost around the $200 AUS, the driver card for it is a little dearer.

Get the manual all will be revealed.!!!!
 

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Discussion Starter #5
Thanks for the reply,


However, I already bought a service manual and it does not seem to have the troubleshooting section you describe. The contents are:


SAFETY PRECAUTIONS

SERVICING PRECAUTIONS

CONTROL DESCRIPTIONS

REPLACING LAMP

SPECIFICATIONS

ADJUSTMENT INSTRUCTIONS

BLOCK DIAGRAM

PRINTED CIRCUIT BOARD

EXPLODED VIEW

EXPLODED VIEW PARTS LIST

REPLACEMENT PARTS LIST

SVC. SHEET


Can you tell me what your service manual suggest as a possible cause for my TVs symptoms?
 

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My manual has a Ladder showing faults for everything like No Video, No sound, No Component, No Power you name it it has it for the TV.

Now I check Item 5 and its LAMP/Ballast and it has a good ladder but in brief as its a mile long with arrows If your lamp is ok you fit it back in and if you have no Ignition you check the SMPS BD (Switch mode p/s board) Socket Number P820= 220V ..... 410V

Socket Number P841= (2 pin) STBY 6 V

Now the P Socket numbers Numbers are for my set not yours so this is ONLY A EXAMPLE But what they are trying to say is if the pins have the voltage at these Sockets at the SMPS your ballast is stuffed or the connection to the ballast are stuffed, if you have no Voltage at these pins check the Fuses and or SMPS Driver board as that might be stuffed. and that about it Its either the LAMP or Ballast or an bad connection or a SMPS Driver board failure if it was my set..I cannot see and control coming from any orther boards like the "Tuner , Digital, Main ETC"
 

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Discussion Starter #7
Well I have just tested the voltage going to the ballast board. It was 375V which is well within spec: Min 360, Typ 380, Max 400.


Is there a technique for testing the high voltage from the ballast? Or is there a way of testing the lamps?


I am pretty sure that the ballast is the problem but I want to be certain before I spend any money!
 
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