Question about Lite On Televison & Video
SOURCE: Neff combi blown diode.
If the diode failed by opening, there may be no other damage. If the dioded failed by shorting, the alternating current may have damaged other components. Ohm it out. You can get diodes from digikey.com, mouser.com, or radio shack or any electronics or appliance supply. If the diode is charred and you can't get the part number, the oven rating can be used to select a replacement. Since the fuse was 10 amps, the diode should also handle at least 10 amps. If you can power the unit and read the voltage at the diode input this will give you the power (volts times amps). It's always worth trying as it's cheaper than replacing the unit.
Posted on Nov 30, 2007
Might be the relay on the power board that stands up just behind the big transformer. I has a complete no power also, I shorted out the relay legs on the black one, it started to work again. I will probably replace it, since the problem started by the system shutting off randomly.
Posted on Nov 29, 2008
At this point you may have bad transformers, bad tuning cap, you need to check the frequency of the inverter oscillator to see if both of them are running at the same frequency, the bad one may not be. The Inverter/power supply is not made by SONY, Powernet makes the board. Please see what went wrong with the one I fixed.
One thing to keep in mind, when the board turn into carbon (blacken), it will conduct. The circuits operate at high voltage and high frequency.
Posted on Apr 09, 2010
I had a similar problem with my 42" set, a re-badged SAMPO unit bought during 2002 in the UK. It was working one day and when turned back on the next day there was no picture. The clicking noises that occur when the set is switch on happened but not in the usual pattern. The symptoms were the same as a fault it had approximately 10 months after I bought it, although it was then repaired under warranty by swapping out the PSU.
I took the back off the set and confirmed it had the LJ44-00025A PSU board. When first plugged in the green LEDs on the PSU would light and the relays would click. There would then be a short buzzing noise, the relays would click and the green LEDs would go out. The red "Alarm" LED would then light.
After reading posts on a number of forums pointing to the PSU being at fault, I ordered a replacement PSU from ADC in the US ($139.00 + shipping) but that did not fix the problem. After downloading the service manual I then followed the instructions to check and set the PSU voltages, during the time that the three green LEDs were lit. I found that the VA value was zero and the others were a lot lower than they should have been. The service manual shows that the voltage tests are carried out with most of the sub-boards connected, except the Image Board and front panel switches. I then disconnected each connector in turn from the PSU and found that when the connector for the Logic F-Buffer board (LJ92-00601A) was disconnected the PSU would not alarm when powered up and the five voltages were close to normal. I found a replacement 2nd hand F-Buffer board on fleabay for about £17.00 and once fitted I re-tested and set the five voltage levels for the PSU. The TV is now working as well as it ever has. I have since tested the original PSU and confirmed that it also works, although the voltage levels needed adjusting. I hope this helps.
Posted on Jul 06, 2010
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