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Re: Dead, no power indications at all
Hi there.there are two 150k resistors in series on the psu,which tend to go open circuit.if this is the case,watch for the main cap as it can bite.switch set on and off,then check for 300 plus volts accross it five mins after switch off.if thats thecase,its those resistors.hope this helps.seve
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It seems that the electrical relay's, it getting completed is not able to create the high voltage required for proper display. Hence on switching it on, the power LED will immediately light up but since the circuit is not completed it switches to standby and then off. Get the relays replaced and make sure you connect the main power chord to a 15 Ampere rating wiring usually the line meant for A/c and hot water Geyser(called as high power line)..........sodeep
Same problem with mine. Relays click, sound, no picture and a flashing power LED. I finally found a schematic online. I went through the high voltage circuits and found the power transistor 2SC5570 was shorted out. There is also a pico fuse in that area but my was not open. I replaced the transistor and prayed the flyback transformer was not shorted. It wasn't, I'm watching my old 36" right now. Not a bad fix (17.00) bucks. Wonder what a service tech would have charged ;)
The main power supply section is not working.
(standby supply is OK)
Common possibilities are:
- High-voltage section (flyback transformer) has failed
(happens sooner or later, about 8 years typical))
- CRT tube has failed overloading the supply
- Power surge has popped the power input circuit.
(Fuse, rectifier diodes, turn-on relay etc)
- One of a hundred of electrolytic capacitors has failed
short overloading the supply. They dry
out with age, are cheap to replace, but hard to find which one it is.
- Or any of many other possibilities.
In short, you need a experianced tech to troubleshoot this.
How old is this set?
I guessing it is maybe 8 years? In that case I would plan on
overhauling the high-voltage circuit because it is going to need it
soon whether it is the problem now or not (and it very likely is).
Should cost under $200 at a shop. I generally don't waste time on
older dead TV's but this is a good model and worth the
effort. The risk is that sometimes when the high-voltage
fails, it blows up other circuits in the TV and can be a real nightmare.
it is due to plug or socket loose or sparking in that area.
if it is ok then it is due to some component failure in power supply of tv.
as per schematic is concern please go to.
go in search & give model no.it is freely available.
as set is dead
the problem is in power supply or horizontal section.
though it is a simple &less time taking.
but if you have no TV repair experience, or any experience tracing circuit flow with a schematic, call in a tech to assist you with this repair. This tv set is not the place to be experiementing inside of. You probably have bad capacitors and transistors in the power supply or the sweep power supply.
whenever fuse blows every time it is the indication of short circuit in tv.
so please do not put fuse unless you know the cause of blowing fuse.
these are the reasons of blowing fuse.
1 main filter cap.short.
2 rectifier diode short.
3 swithing transistor short
4 horizontal output transistor short
5 caps & diodes connected to flyback transformer short.
6 print short.
7 at last if every thing ok then flyback transformer defective.
hope this will help.
if you are not a tech person call skilled tech to fix it.
as you have seen inside that no power & no light.
problem seems to be in power supply.
1 check fuse.
2 check switching ckt.
3 check for loose contact or print break.
4 now if you get power on & still tv is not ok then check for hor. output transistor in hor. output stage.
if you are not tech person please do not try to fix it as high voltage is there inside.
NEVER EVER replace a fuse and think that va fuse will blow all by itself. The fuses are there to protect the set from catching on fire incase theres a short inside the set. Now in some cases an intermittant short can work after you replace the fuse but if its burnt black or brownish, theres a short inside the set in one of the circuits. always use a 100 watt light bulb across a blown fuse if your not sure if there is a short. if there is, the light will absorb the short and glow bright. if there is no short the bulb will glow bright , then go down very dim. you could have a main power supply problem, such as shorted bridge rectifyers,shorted main b+ capacitor, Hot could be shorted, or the Vertical or audio output IC could be shorted