Hi, I have Plasma TV Power Supply Board. The model of board is: LJ44-00144A PS-506-PH. The stand-by voltage 5Vstb works just fine. When I turn on the TV the Stand-by let in front of it comes blue like working. But there is no voltage on the power supply board except 12Vssb, 5Vsw and 5Vstb. The missing voltages are: Vs= 210V Va= 60V Vg= 15V D5V 12Val 8V6 Can anyone help me about this issue?

I would suggest that the fault lies downstream from the boards. If there was a surge and some transient voltage got sent to the screen I'd guess that you've got a short that you may never be able to find.

1. Measure the stand-By voltage if is there on the power supply, if not replace the power supply.
2. If the stand-by voltage is OK, change the main board.

Hi,
First of all the power supply makes 'Stand By 5 or 3.5V which goes to main board. When we give power on command to the TV the main board sends 'stand by or Power ON' command to the power board which then makes other necessary voltage for the main board as well as other sections. If the power board does not receive 'Power On' command from main board, it will not produce the necessary voltages to operate the TV set.

Check your stand by voltage on main board and power supply cable..should see marking on PS for Stby 5v. I you have the 5v change main board or A board it is not supplying your voltage back to PS to turn on. If you dont have 5v stand by change PS.

Hello
The power regulator board in your Hitachi is not switching. It is an SMPS [Switched Mode Power Supply]. Normally for plasma TVs the power supply repair will be almost impossibele due to lack of component availability. If the fuse is OK, definitley the switching process has failed it it. There is an IC which oscillates at high frequency, whic its oscillation signals are given to MOSFET transistors to chop the incoming AC, converted DC voltage. These switched voltage is passed through SMPS transofrmers which it turn generates secondary voltages that goes to different circuit boards of your TV. The power board is the most important section in a Plasma TV. it must be perfect in every respect in terms of secondary voltages. If any one of this voltage goes over than specified, the main boar will get damaged. So it is adviced to replace it as card basis, rather than making "sugery" to it. The power supply board can be had from Authorised Hitachi Service centers. You just give the the exact model number of your Hitachi TV. They will give you the orginal power supply board. Never play experiments with Plasma TV. OK.

You are better off replacing the power supply board. Usually the mother board will output a power ok signal to turn on the TV only when the power supply is working correctly (all voltages are within specs), similar to a computer, having said so, if you have the schematics you can verify those voltages being output from the power supply upon depressing the power button. The +5v stand by voltage is most likely ok, since the mother board is at least providing you with the blinking light. It is the +12V and +24V which are not being output, along with any other auxiliary voltages. I would suggest either having a replacement board (power PCB) installed or otherwise feeding the needed voltages by substituting those missing ones with a variable DC power supply, just to verify it. Follow above only if familiar with electronics and electricity. safety first!.


http://www.HDalacarte.com guy audio/video/computer technician for over 30 years

Hi


Thanks for using FixYa. These kinds of issues in plasmas usually occur after 3-4years as plasma TV is a very hard working device. It is working harder than any TV that has been built before, and as a result it produces a lot of heat. 75% of technical problems in plasma TV's are caused by overheating problems. You’ll need to check the power supply board first for any swollen/bulged capacitors. As power supply board is the hardest working board in a plasma TV, it develops voltage to supply all components, high current + high voltage. All this is only recommended if you have electrical expertise & know how to solder/re-solder components as these units contain high voltages even when switched off. Please do accept the solution if the issue is resolved or post a comment for further assistance.


Thanks
Rylee

Hi


Thanks for using FixYa. A plasma TV is a very hard working device. It is working harder than any TV that has been built before, and as a result it produces a lot of heat. 75% of technical problems in plasma TV's are caused by overheating problems. You’ll need to check the power supply board first for any swollen/bulged/leaky capacitors. As power supply board is the hardest working board in a plasma TV, it develops voltage to supply all components, high current + high voltage. All this is only recommended if you have electrical expertise & know how to solder/re-solder components as these units contain high voltages even when switched off. Please do accept the solution if the issue is resolved or else revert for further assistance.


Thanks
Rylee

Hi,

I have seen this once before and the reason was a capacitor on power supply board.

My bet would be Power Supply board, before we troubleshoot anything else. Check the continuity of the board. There might be many capacitors or diodes. Check the voltage across them. Sometimes, you can find a faulty capacitor by naked eye. Usually, the defective one are swelled.

Hope i helped you.

Thanks for using ' Fixya ' and have a nice day!!

I had the same problem... Astar 30" LTV 3001 ....These TV's have a cooling problem that causes premature electrolytic capacitor failure. De-solder and Test all the 2200uF-25v, 3300uF-35v and 1000uF-10v caps in the power supply (center board, back of TV). Use a good LCR meter that will read 3300uF or better, Replace all bad caps with 105c rated caps. If you don't have an LCR meter, replace all the mentioned caps on the PS. If fuse on board is blown, also replace the F9222L regulator IC chip. Mounting a small cooling fan on rear of TV over the PS will help keep your new caps from failing again. This requires holes in the stand bracket and the rear of the TV, power can be supplied from a 14V source near the bottom of the PS board.