Toshiba md 20f51 07/2005

Have you checked whether mains power reaches the power board? Check it first. If yes, the power board you purchased newly should be checked.

If fuse blows off, the power supply regulator section circuit to your TV should be checked in detail. Check all the rectifier diodes first. Then check the main switching transistor for short. The work is a semi skilled one. For more information, check the link http://electronicshelponline.blogspot.com/

The fuse blown because theres a short circuit connection in the PCB power supply of your television.Please check the power supply inside,remove the back cover to see the power supply section.unplug first to avoid electric shock.Will you check the bridge type diode first.If the bridge type diode or diodes is shorted the fuse is always blown.Using digital tester check diodes,regulator transistor,and other transistor around the power supply.

Hello talwar,
Hi, the easy level would be to check for the following parts 1. fuse, if open, replace 2. faulty switch, check for continuity using a multi-tester device. 3. check open wire/power cable
if this cannot solve the problem.
this would be the hard part 1. If the fuse replaced, exploded again, check for shorted parts like regulators, diodes, capacitors. 2.the fuse is good but still no power, this is power supply failure, needs service. (there is too much explanation and testing involve)
call your local service shop for a job. thats it.

en francais

le modul est fixé sur l'ecran
sur ce modul verifier si vous avez 3.3 volt (trois regulatuer avec un test point) si vous n'avez pas 3.3 verifier les deux fusibles F1 et F2
F1 devrais etre ouvert ....
bonne tv ;)

module is fixed on the screen

this modul check if you have 3.3 volts (three regulatuer with a test point) if you do not have 3.3 Check both fuses F1 and F2

F1 should be open ....

good tv;)

firstly check your sleeping timer set ups. if that is okey, then check the following
the power supply components eg
power transistor on the power supply lekage
zener diodes, power diodes of the bridge rectifier.
in short the supply is drowing to much current, hence semiconductors are heating up and reach a cutoff point, and saturates

the tv is fault, there is a lekage to ground, cause 5 amps is avery high current. plse take your tv to a w/shop and have the following checked
i rectifier diodes
ii power transistor, driver transistors, diodes, zener diodes
iii fusable resistors near the power transistor
iv making sure that a 90-110volts is getting out of the power supply to a line transistor, near the line trasformer.
the problem will be over

first remove all the dust from smps then check power cord output by multimeter whether right or not ok then open and you will find one fuse there check it without supply if open then replace it if not then check whether a.c. supply reaches or not if present then check the thermister resistance it should be low also check the dry solder if present then remove it please check dc supply at primary filter (big cylendrical capacitor) if not present then 4 bridge rectifier diodes may faulty replace it

two things can be affected, a tuner if you were using out door
the other one is the power supply. the tv sensed a high voltage (surge)
firstly you need to repair a supply, check the following.
i rectifier diodes at the power supply
ii power trasistor, driver trasistors diodes, zener diodes
ii fusable resistor near a power transistor
after the tv will come on ----if they will be light on the tube then test a tuner, by putting in signal.

you have to check the power supply, take your tv to w/shop
ask them to check the following
switch, semi conductors like diodes , transistors, and zener diodes. also dont forget to test fusible resistors. on the power supply