Question about Toshiba 57H81 57" Rear Projection Television

1 Answer

Toshiba 57H81 Have both power/deflection and sig/conv printed circuit assemblies out of set. No shorts or low resistance paths show on either the +16 volt or +32 volt supply lines on either board. I have seen other sites with horror stories about this set regarding the convergence IC's and fuses which are suspect in this set. I'm capable of removing the two convergence IC's (STK392-110)'s and replacing them. I think the heat sink should be removed for easier replacement as screws that mount IC's are blocked. Techman has recommended replacing the IC's along with the fuses I mentioned. It will probably cost a couple hundred dollars for the parts but I don't have any other ideas at this point. The bad thing is the IC's may have nothing to do with the problem that caused the fuses to blow. Are there other experts that have experience with the Toshiba 57H81 that can offer any ideas that may help get the set up and running. TIA, C5Z06

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  • 2 more comments 
  • Fred Macciocchi Oct 14, 2006

    Thanks again for your help Techman.
    Ordered parts from partstore.com. 8 to 10 days.
    I'll remove IC's ahead of time. Fuses too.
    I'll report back whether the components fix my problem.
    C5Z06

  • Fred Macciocchi Oct 15, 2006

    Hello Techman,
    Thanks again for your input. I have the schematic and will use the right amount of silicon grease for good thermal transfer.
    C5Z06

  • Fred Macciocchi Oct 16, 2006

    Techman,
    I can send you a copy of the schematic in PDF.
    Need your email. If you don't want it posted
    then ask Barak and I'll send it to him and he
    can send it to you.
    C5Z06

  • papa224u Mar 14, 2008

    I do not have the part number for the convergence, cansomeone help me with this.



    thanks.

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  • Master
  • 3,130 Answers

These ICs are the Japan types and available from partstore.com under part number C5AA00000108 for $29.08 + shipping apeice. These are original replacements for the panasonic parts. Good Luck Ps please do not forget to rate this

Posted on Oct 14, 2006

  • Larry  Dillon
    Larry Dillon Oct 15, 2006

    If you need more assistance and know how to read a schematic, send me a copy via email if you can and we will see where to go from there. One should be available if you need on athttp://www.servicemanuals.net . Oh make sure you use plenty of heat sink grease on the IC and the heat sink. Thats a common mistake made by servicers all the time, they forget to add more grease and the parts don't hold up for more then a few weeks. You should be able to get some heat sink grease from radio shack or maybe from the partstore. Look up the number on the net and call them and see or like I said get a small tube from radio shack.

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What's your problem?40-42 inch Theater View Toshiba TV, Date on TV is June 1999. Picture slowly started shrinking from up and down. Model no. TZ50V51 Serial no. 77988872 chasis no. 9951


you're experiencing a vertical deflection issue and will most likely need to replace the deflection board. You can get a deflection board for your model from www.tvrepairworld.com

Oct 18, 2011 | Toshiba 57H81 57" Rear Projection...

1 Answer

In my tv fuse is blowing off immediately


Hello
If fuse blows off immediately, i means that there is a short circuit occured in your telivision. This can mainly due to some diodes or regulators inside your tv. An overvoltage, spikes, ie [sudden high rise and go low], in the supply votage in your home, could damage power supply regulator components inside your tv.
All Sony Tvs has high accuracy power regulating systems inside. It is an onboard assembly, usually take 1/4th of the area of the TV. In older Sony TVs, this section was built in with use of transistors of different types. But your tv is not so old, so its power supply system is built with an STR, an Ic meant only for power regulations. Normally it willb numbered STR S6707, STR S6703 etc; according th the working voltage of the main board, and screen size of the TV.
This STR may get shorted due to power fluctuations, or any other reasons. A I mentioned above this is an Ic look like small squuare biscut of about an inch in square, and will be black in colour.
The rectified main power supply is given to it via an SMPS transformer [Swiched Mode Transformer], and the Ic will swictch it on and off at the rate of sbout 25KHz or more, and this transformeres secondary voltage is used to power up the other part of the ciiruit board.
If the fuse is blowing as soon as the set is switched on, this Ic will be faulty [Shorted inside]. If you put an another fuse, it also will blow up due to short. It is not good to play with power supply system by doing this as it may harm to other components also.
You have done it I thinks. Here in India, we gets 220VAC as home power supply. Sony TVs used here have a fuse rateing of 250V 3.5Amps. If your household supply system voltage is also this you must put only this rated fuse. If it is 110 or 120VAC, the fuse rating may differ; and will go upto 6 to7 Amps. More than this rated fuse should not be used.
You just do one thing. Just open the back cover of the TV, locate the power regulator section, and chech whether any main rectifier diodes for leak. There may four of them. In some sony Tvs, rectifier stalks are used. Check it for leak. If thery are all good, measure the resistance across the main filter capacitor with a multimeter set in Ohms range. If the STR said above is short, the meter will give full scale deflection. Unsoder the STR and pick it out after loosing its fixing screws to the heat sink. Again check the resistance accross the main filter capacitor. It must sho a low deflection or no deflection at all. Never replace the STR with a new one as there may be some other faulty components in that section. Usually when STR fails, there are some Zener diodes, Wire wound resistor etc will also gets shrted. If you replce the STR before checking them for fault, the STR you puts in will get shorted as you swich on the set. It will take just 1/100 part of a second.
So check all the components related with power regulator system, and then only repace the regulator. Caution: Keep chlidren away from you while you open the tv. Never touch any part of the circuit board while power supply is there. Plug out from the wall socket each time you touch the printed circuit board. As your Tv screen size is 32", an approximate of 25KVDC [15,000VDC], will be present at the first anode of the picture tube while it is working. It is too dagerous to contact.
If you haven't through knoledge, skill and patience, never try to repair it. If you knows to follow its schematic digram, buy one book and follow the circuit.
Keep an adult beside you as you try to repair your set, as a precaution.
If you have any doubt, report to Fixya, they will give me alert. Ok

Oct 20, 2010 | Sony FD Trinitron WEGA KV-32FS120 32" TV

2 Answers

Dash lights went out, so i had some fuses removed to see which one was bad. next thing i know the airbag light was on.


You just need to turn it off again. You created a false trigger of the light. You may have to have dealer do it with scan tool.


Prove Out Procedure
Turn the ignition switch from the OFF to the RUN position and visually monitor the air bag indicator with the air bag modules or restraint system diagnostic tools installed. The air bag indicator will light continuously for approximately six seconds and then turn off. If an air bag supplemental restraint system (SRS) fault is present, the air bag indicator will either:
  • fail to light.
  • remain lit continuously.
  • flash.
The flashing might not occur until approximately 30 seconds after the ignition switch has been turned from the OFF to the RUN position. This is the time required for the restraints control module (RCM) to complete the testing of the SRS. If the air bag indicator is inoperative and an SRS fault exists, a chime will sound in a pattern of five sets of five beeps. If this occurs, the air bag indicator will need to be repaired before diagnosis can continue.
----------------------------------------------------------- Restraints Control Module (RCM)
The restraints control module (RCM) performs the following functions:
  • signals the inflators to deploy the air bags in the event of a deployable crash.
  • monitors the air bag supplemental restraint system (SRS) for faults.
  • illuminates the air bag indicator if a fault is detected.
  • flashes the air bag indicator to indicate the lamp fault code (LFC) detected.
  • communicates through the data link connector (DLC) the current or historical diagnostic trouble codes (DTCs).
  • signals the generic electronic module (GEM) to activate a chime if the air bag indicator is not available and another SRS fault exists.
NOTE: The safing sensor is internal to the RCM and is not repaired separately.
The RCM monitors the SRS for possible faults. If a fault is detected while the ignition switch is in the RUN position, the RCM will illuminate the air bag indicator located in the instrument cluster.
When the ignition is cycled (turned off and then on), the air bag indicator will begin its prove out sequence. During prove out the air bag indicator will illuminate for six seconds, go off for two seconds and then, if a system fault exists, flash the two-digit LFC. The air bag indicator will flash the LFC five times, then it will remain illuminated for the rest of the key cycle. The RCM will also communicate the current and historical DTCs through the DLC, using a scan tool. If the air bag indicator does not function, and the system detects a fault condition, the RCM will signal the GEM to activate an audible chime. The chime is a series of five sets of five tone bursts. If the chime is heard, the SRS and the air bag indicator require repair.
LFCs are prioritized. If two or more faults occur at the same time, the fault having the highest priority will be displayed. After that fault has been corrected, the next highest priority fault will be displayed.
The RCM includes a backup power supply. This feature provides sufficient backup power to deploy the air bags in the event that the ignition circuit is damaged in a collision before the safing and air bag sensors determine that deployment is required. The backup power supply will deplete its stored energy approximately one minute after the battery ground cable is disconnected.
Electrical System
The electrical system that supports the air bag supplemental restraint system (SRS):
  • is powered from the battery through the ignition circuit.
  • provides the electrical path from the restraints control module (RCM) to the air bag modules.
  • provides the electrical path from the RCM to the air bag indicator.
  • provides the electrical path from the RCM to the data link connector (DLC).
  • provides the electrical path from the RCM to the generic electronic module (GEM).
----------------------------------------------------------
Restraints Control Module (RCM) Diagnostic Trouble Code (DTC) Priority Table DTC a LFC b LFC Priority Description Action To Take — — 1 The Air Bag Indicator is Illuminated Continuously — RCM Disconnected, Inoperative, or Lost/Low Ignition Feed Go To Pinpoint Test A . B1342 24 2 RCM Is Faulted INSTALL a new RCM. B1231 19 3 RCM Crash Data Memory Full INSTALL a new RCM. B1921 21 4 RCM Bracket Ground Resistance High Go To Pinpoint Test B . C1414 29 5 Incorrect Vehicle Identification Code Go To Pinpoint Test C . B1887 15 6 Driver Air Bag Circuit Shorted to Ground B1916 15 7 Driver Air Bag Circuit Shorted to Battery or Ignition B1888 16 8 Passenger Air Bag Circuit Shorted to Ground B1925 16 9 Passenger Air Bag Circuit Shorted to Battery or Ignition B1932 32 10 Driver Air Bag Circuit Resistance High B1933 33 11 Passenger Air Bag Circuit Resistance High B1934 34 12 Driver Air Bag Circuit Resistance Low B1935 35 13 Passenger Air Bag Circuit Resistance Low B1892 — 17 Air Bag Tone Warning Indicator Circuit Shorted to Ground or Open B1891 — 18 Air Bag Tone Warning Indicator Circuit Shorted to Battery or Ignition B1869 Tone c 19 Air Bag Indicator Inoperative B1870 Tone c 20 Air Bag Indicator Shorted to Battery — — — No Communication with the Restraints Control Module

Feb 24, 2010 | 2004 Ford Mustang

2 Answers

Put in new conv. ics, almost finished manual alignment,set chirped and went black, power button blinks and shuts down power


Pull the Sub Yoke Connectors plugs from the Convergence circuit and turn the set on. If it stays on, one of the Convergence IC's went bad. It is not unusual for them to be defective new out of the bag. If possible I would use STK392-120's instead of STK392-110's if they were the original IC'S in the set. If the set does not start, I would look at the Hv Output Transistor or the Horizontal Output Transistor being shorted.
Hope this helps,
Skyassoc

Dec 02, 2009 | Hitachi 53UDX10B 53" Rear Projection...

1 Answer

Blinking power light & black screen on toshiba 57h81


This TV could have one of several problems including but not limited to; convergence IC's,bad capacitors, shorted horizontal output transistor. Call a good TV Tech. Check with the BBB before you decide on one.

Jul 11, 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

57h82 toshiba projection tv


sounds like a bad capacitor in the deflection circuit.

Mar 17, 2008 | Toshiba 57H81 57" Rear Projection...

1 Answer

Toshiba 57H81


Check all fuses in the power supply and look for any bad connrctions on the PCB. You are probably missing the 130 volt supply to the horizontal circuit. Common reasons are: Shorted horiz output transistor; flyback transformer, picture tube arcing , bad power regulator IC. In short, you need to get a qualified tech for this symptom. Hope this helps.

Oct 29, 2007 | Toshiba 57H81 57" Rear Projection...

2 Answers

Toshiba 57H81 circuit board removal


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

Oct 08, 2006 | Toshiba 57H81 57" Rear Projection...

2 Answers

Flashing LED on front panel


The place is call wwww.servicemanuals.net ,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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