Question about Toshiba 57H81 57" Rear Projection Television

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Toshiba 57H81 circuit board removal

I now have the schematic and believe my problem which is the flashing red pwr on led and set not powering up may be a bad component on the "power and deflection" board (PDB). I need to remove it to run some static tests on at least the horizontal output transistor, fuses, etc. There are two white plastic connectors and one blue plastic connector on the right edge (viewed from rear of set) of the PDB. The white connectors pop open and up but I haven't figured out how the blue connector opens. Has anyone with experience had the PDB out and can provide any help with its removal. There are screws around the perimeter and some in the middle of the PDB also. There is slack in some of the cabling and think I can some checks once board is at least partially removed. It will have to be removed to replace components anyway. Most components on this board are "thru-hole" and not surface mount devices. The schematic itself is on 20 pages and not legible unless viewed as at least 11"x17" sheets. You can blow it up on the computer monitor but then you can't see how things are interconnected. I'm guessing maybe low voltage regulator IC or possibly one of the deflection transistors. There are many other possibilities but this is a starting point. The flashing led may be indicating that the low voltage power supply circuits have an excessive load on them and the supply itself is folding back and shutting down. This can result in an oscillatory condition where the power on led flashes.

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Re: Toshiba 57H81 circuit board removal

The blue connector pops up the same as the white,from the power/deflection side.

Posted on Jan 20, 2007

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Re: Toshiba 57H81 circuit board removal

Post a Picture or the service manual here on this page and maybe someone can assist you.

Posted on Oct 09, 2006

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Hitachi 65SWX20B no picture/sound, 4 out of 5 green LEDs on, red LEDs on, green B+ LED is off. Pwr Relay clicks on, TV only turns on/off. IP02 location/How to check for 14-20V on terminal 4 of IP02?

Fault at its main digital board. Short circuited component/s at it. Contact any service technician; or the authorized service center. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts.
In most cases, the main board might have to be replaced. If so, a software [firmware] update too might be necessary.

Sep 20, 2016 | Hitachi Projection Televisions

1 Answer

Toshiba 57H81 Rear Projection TV Problem

IT is possible that the power connector in the back of the set is either faulty or broken, you would have to go into the back of the set, and look and see in the connector to the power board isloose, if it is, then you might be able to resolder it on. If not, then there is a problem with the plug, try a different outlet.

Jan 10, 2008 | Toshiba 57H81 57" Rear Projection...

1 Answer

Red color convergence on Toshiba 57H81

Often convergence issues do not require the entire board to be replaced. You can resolve it by replacing the convergence ICs. The part in question is STK392-110. You will need two of them and they cost around 10$ each. But replacing them is a pretty complicated procedure and I would not suggest it to someone without prior experience. A service manual should get you started in the right direction if you are planning to do this yourself.

: Disconnect from the power supply before you start the repair. Also read the legend, the hv circuits are denoted by a special symbol, so you will know what you shouldn't touch.

You may also need to replace the nearby resistors that may have popped the IC in the first place. Read the service manual for further details.

Good luck,

Apr 01, 2009 | Toshiba 57H81 57" Rear Projection...

2 Answers

Toshiba 57H81, power to transformer and flyback.


Jan 22, 2009 | Toshiba 57H81 57" Rear Projection...

3 Answers

Toshiba 57H81 Flashing Red Power Light, Blown Fused F850+F852

Solved by resoldering some solder joints!!!!!!!
Toshiba Model 57H81 Rear Projection TV - Purchased 11-09-2001

Problem: Toshiba 57H81 Flashing Red Power Light, No Picture/Sound, Blown Fuses F850 + F852

Symptoms January, 2009:

  • Upon turning on set I got flashing red power light and nothing else.
  • Removing plug for one minute and plugging in results in:
    • Audible click, steady red power light for 2 seconds then slow flashing red light
    • Pushing power button results in steady red for about 2 seconds then slow flashing red light, no other set activity
  • Removing power cord for several hours and plugging back in made no change
    • Audible click, steady red for about 2 seconds then slow flashing red light
  • Possible related note: Over past several months occasionally the entire screen would flicker momentarily and at other times be problem free for weeks.
  • Fuses F850 and F852 found blown

Repairs Made:
  • PD0074 DEF/CON Power Board
    • There are two main power supply capacitors in this set. They are C-809 and C-810. One their negative lead on the printed circuit board re-soldered leads and nearby contacts. I’m told that because the factory left out a printed circuit board eyelet, the connection will come loose over time. When I called Toshiba customer service they said there was a known solder joint problem causing blinking red light.
    • Replaced blown fuses F850 and F852.
      • I actually installed a fuse panel on the inside of the cabinet and routed the fuse connections here instead of ordering the special fuses and replacing them on the circuit board.
      • Had to use a 5 Amp SLO-BLOW for F850. Fast blow does not survive power up. Get the red blinking light.
      • Used a fast blow 2 Amp for F852.
  • PD0073 SIGNAL Board
    • Re-soldered Q751 + Q752 STK392-110 Convergence Amps
    • Re-soldered adjacent pads that looks suspicious

Total Cost to Repair about $10
  • Twelve hours of my time over three days to research issue, disassemble set, make repairs, add fuse panel.
  • Already owned Service Manual and Circuit diagrams from a different 2004 repair.
  • Less than ten dollars at Radio Shack for fuses and fuse panel. Already had wires, etc.
  • Some solder. Already owned de-soldering tools, etc.
  • Visited both local authorized Toshiba factory service repair facilities. One said repair would have to include replacing Q751 + Q752 STK392-110 Convergence Amps with ST392-180, and realigning set for a total of $500+ and it would be more if they had to order a power board. NO THANK YOU! Other shop said $65 for site visit and $30 to make an estimate that could be applied to repair.

Jan 04, 2009 | Toshiba 57H81 57" Rear Projection...

1 Answer

Blinking red light

Your TV is in shutdown. Unplug the set from the wall and wait 30 seconds. Apply power and see if the set comes back on. If the problem is the same (red blinking light) then you need to call a repairman. The most likely suspects are the convergence chips , vertical loss, power regulator or horizontal circuit problems. The shutdown circuit monitors multiple circuits for voltage and current malfunctions. That is why you need someone trained to troubleshoot the problem. Good luck!

Nov 23, 2008 | Toshiba 57H81 57" Rear Projection...

1 Answer

Tv won't turn on

You will need a service manual to troubleshoot the set to be able to find whats going on with it . Its in shutdown mode with the led flashing. A good manual is available at this link.

Mar 19, 2008 | Toshiba 57H81 57" Rear Projection...

2 Answers

Flashing LED on front panel

The place is call ,you can get it download or a paper copy,for this set I dont know the price but it will give it to you when you put the model number.Check for shorted horizontal output and loose conections,sometimes intermitant conection damage this transistor.Be careful

Oct 04, 2006 | Toshiba 57H81 57" Rear Projection...

3 Answers

Flashing red light

You might want to check the first Item talks about power LED lights Power supply does not start

Sep 27, 2006 | Toshiba 57H81 57" Rear Projection...

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