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.

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Re: Low voltage power supply fuses blown

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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Re: Low voltage power supply fuses blown

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

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Re: Low voltage power supply fuses blown

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

Jun 25, 2014 | Samsung HCM5525W 55" Rear Projection...

2 Answers

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

Nov 27, 2010 | Toshiba 57HX81 57" Rear Projection...

2 Answers


Your tv might have a defective power supply, and/or convergence circuit. The initial cause of the problem, if it is the convergence circuit, is usualy a loose conection on one or two jumpers close to the convergence output circuits (STK392-1110), in with case this chips might need to be replaced and a pico fuse of 5A on the power supply too. I hope this help you.

Sep 24, 2009 | Toshiba 56H80 56" Rear Projection...

1 Answer

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.

Jan 28, 2009 | Toshiba TP43H60 43" Television

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

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.

Mar 30, 2008 | Toshiba 50HX81 50" Rear Projection...

2 Answers

Tv not powering up

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.

Oct 23, 2007 | Toshiba TW40F80 40" Rear Projection...

1 Answer

Toshiba 50H81 TAC0151 Blowing Fuses, I Need schematic

Well without the schematic, knowing Toshiba they have alot of convergence problems, so see if the fuse blown in the convergence area, if you you may have to replace convergence amps. These are the big STK's. Most of the time there was a color problem with set before going out. If no problem with this on your set then look in the HV area Hor. and Ver. area. Hope this helps!

Sep 09, 2007 | Toshiba 50H81 50" Rear Projection...

1 Answer

No power, LED blinking, Low voltage regulator IC?

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

May 22, 2007 | Toshiba 57HX81 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...

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