Question about Toshiba 57H81 57" Rear Projection Television

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Low voltage power supply fuses blown

Fuse F850 and F852 are open. They are part of the 16 volt and 32 volt supplies that are used by the convergence board. I still have not removed the power/def board but will need to. I believe the 32 volt supply is developed with a doubler circuit and both fuses being blown in the same area indicate the problem may be the supply components themselves. Capacitors, bridge or single rectifiers for example. Does anyone have any experience with this particular problem? Still haven't figured out how to disconnect the blue connector which connects the two circuit boards. The white connectors (2) disconnect and I assume the blue must have a similar mechanism.

Posted by Anonymous on

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  • Anonymous Oct 11, 2006

    OK Thanks for your input Techman. Where can I get the parts to fix the set? I have one location in Ohio Fox Electronics I think. Can you identify the IC's that usually blow on the convergence board? TIA for any help you can provide.

  • Anonymous Oct 11, 2006

    I was able to pop the connectors open (2 white and 1 blue) with a small screwdriver. Removing the power/def board was necessary to replace the fuses properly. If the convergence board is the one to the right of the power/def board I'll need to remove it too.

  • Anonymous Oct 13, 2006

    I see the two IC's on the board with the large heat sinks on them.
    Do you know from experience that the IC's blow? They look tough to get at as they are blocked by a tuner vertically mounted on the PCB. I see the IC's use the +32 volts that had a fuse blown but not the +16 volt which also had a fuse blown. There could have been a load an the 16 volts too. I hate to change the fuses and IC's without knowing I've fixed the problem. What info. can you give me? I'm assuming these are the convergence IC's your solution mentioned. I located them by tracing the +32 volt line.

  • Anonymous Jan 25, 2007

    I mentioned this in another post and that was my problem too. This is normally a $400 repair charge.



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Mark Templeton

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Where exactly are the fuses? I am having the power light blinking problem all of a sudden. About a year ago I replaced the convergence ICs. The first fuse I see is the F850, and it is right behind where the power plug is attached to the power board. No problem with that fuse that I can see. I am gathering there are other fuses. It sounds like they may be around the convergence board. Any help in locating these fuses for inspection would be greatly appreciated.

Posted on Jan 31, 2007



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Theres two jumper wires around the convergence ic's that supply the +/-32 volts to them.I found a cold solder joint on one of them.This causes the fuses to blow.Their close to the edge where the two boards meet.

Posted on Jan 25, 2007

  • Anonymous Feb 04, 2007

    There are 8 pico fuses on the power board.Most are black and 1or 2 green.Look for a green one at the front center of the power board.They all begin with "f".The convergence ic,s are on the (SSB)small signal board.Check for bad connection around convergence ic,s and replace bad fuses.If set is still dead unsolder convergence ic,s (completely).Turn set on for 4 or 5 seconds, if it comes on replace ic,s with higher watt ic,s 392-110 are 110 watts try 150 watts.Also try unsoldering audio ic.




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If the convergence power supply fuses blew you can bet that the convergence ICs need to be changed. The blue connector will be pressed down on the rear of the connector to release or pulled up on the back end of the socket. Ps dont forget to rate this.

Posted on Oct 11, 2006

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Wher is fuse fd102s located

check fuse FD802A on the power supply board it is also feeding the -30 volt line. FD102S is on the convergence board 3.5 amp pico fuse cb6844a9-6247-49fc-a85b-fbc69d68a3ea.jpg

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I have A toshiba 57HX81 tv red ligth blicking.i found (2)5 amp pico fuses at F850 & F851 & (1) pico fuse 2AMP at F852 would replacing these fuses bring the tv back to life.

Too many possibilities to predict if the fuse replacements will make the set function again but I suspect your main power supply has failed so if the fuses blow after replacement, you may have to have the supply repaired or replace it.
You might check, using your model number, at the site below to see if they have a power supply 'pull' available from their stock. They part out retired sets of all kinds.
Jimmy's Parts

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I have a TP43H60 toshiba and the power light continues to blink red and there is no picture or sound. I can't turn it off either unless I unplug it??

You have blown one of the pecos fuses, probably the f850 or f852, you can test them with the power unpluggrd and with an ohm meter. Replace them with only the recommended amps fuse. Your set is going into standby, because of the blown fuse.

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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.

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1 Answer

Toshiba TV 50HX81

Check fuses on Power Supply board (F850, F851, F852) and all other fuses. Replace blown fuses (will need an ohm meter to check fuses). I would also replace the two convergence amps (STK392-110's on the signal board, the big black ICs on the two heat sinks). This worked for me.

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1 Answer

Fuse blown

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2 Answers

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Check micro fuses in power supply,Ex. F851,F852,etc.
Common cause is convergence IC's are bad,located on large heat sinks.let me know....T.

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Toshiba 50H81 TAC0151 Blowing Fuses, I Need schematic

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check for bad solder connections then check all fuses the ones that look like resistors too get back to me

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