Question about Zenith B25A74R 25" TV

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Sound Problem When I turn on my television I immediately get a high pitched sound that does not go away. I have a piture but the high pitched squealing sound stays there. How can I resolve this problem.

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Re: Sound Problem

This is a very common problem, caused by failure of IC MM201 (usually located on the plug-in board containing the IF can, which you should also repair as long as you're taking the board out; solder connections commonly fail on this board causing intermittent or total loss of tuner video). The high-pitch whistle's the most common symptom, but it can cause a number of things. Any time there's a sound problem such as low or distorted sound, whistles, static, etc, change the IC. It's available from MCM Electronics for about $15 There is a kit of surface-mount caps available which supposedly will repair these little buggers. It's not worth the time and effort, just put in a new one. BTW, replacing the part is not difficult, but does require soldering skills. If you're not comfortable with soldering, you could remove the entire circuit panel (I believe the M board) and take it to a shop. If you call around, you should be able to find a servicer to replace the part for a nominal fee.

Posted on Mar 21, 2006

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I have a samsung neo 32 inch picture tube tv. When I turn it on there is no picture or sound, but there is a light high pitched noise.

That high pitched sound is likely the Horizontal Output section trying to work. It operates at 15,750 Hz or at the upper end of normal human ears.
It will sound like a high pitched whine.

This is a section or your television that you don't want to fool with unless you are quite familiar with servicing your set. There are very high voltages involved and only a qualified technician should tend to this defect. It maybe easy to fix or it may be quite involved. Get an estimate first then decide to go further or not. There is a potential fire hazard here so don't operate your set until this is resolved.


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1 Answer

When i plug the tv in, i get a high pitched sound

It seems that your unit has some sort of PSU fault, or a problem that is shutting down the Power Supply Unit, PSU. This happens so that no further damage, and possible fire will occur.
You need to take the unit to a reputable service centre/man and ask for a firm "Quote" for the work to be done. It is that "sound" that gives it away, this is a typical switchmode Power Supply problem

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1 Answer

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This set has a shorted horizontal output transistor and possibly a bad high voltage transformer. If you repair the set, also solder the horizontal drive for the transistor listed above. Try for parts. the h-ouput transistor is p/n: 223942 and the transformer is 223952 .Thanks and good luck.

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the horizonal output transistor is shorted-replace it also resolder coil near transistor-if output shorts again flyback transformer is bad

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it could be either the coils on the yoke of the tube or the flyback. flyback would need to be replaced it that is the problem

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1 Answer

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The mainboard might have some loose components, or cold solder , or may be the filter capacitors are becoming faulty. Yes it is worth repairing, bring it to the repair shop. Cheers.

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1 Answer

No picture no sound only the power light turn on and off

Hmm, sounds like a fuse has blown, and this is a problem that I recommend only those comfortable around high voltages try to fix......

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2 Answers

Weird noise over everything

According to the Samsung website: "The high pitched sound you hear is probably coming from the flyback transformer. The flyback transformer converts the relatively low voltage electricity that comes from the outlet in your home to the high voltage electricity needed to drive the cathode ray tube in your TV. It is not unusual for a flyback transformer to buzz softly when it operates. However, if the sound is loud and high pitched, it probably means the transformer is failing. To eliminate the sound, you will have to get your TV serviced."

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1 Answer

High pitch sound for Sony FD Trinitron WEGA KV-27HS420 27" TV

The high pitch squeal you hear is usually caused by a coil vibrating, normally in the horizontal circuit. I've also seen the ferrite bead on the horizontal output transistor do this, but, it is rare. I normally will repair this by finding the coil and "tightening" it. To tighten a coil, technicians use different chemicals, such as, a hot glue gun, rubber silicone or even finger nail polish. I will find the coil that screams by starting with the usual suspects and using a wooden dowel, barely touch the coil and if the pitch of the noise changes, then, thats the coil that needs repaired. If you do not know your way around the inside of a television, I never recommend you do so, since, this procedure must be done with the set turned on and you poke your hands around the inside of the set by the high voltage circuit. Hope this helps your decision.

Mar 04, 2007 | Sony FD Trinitron WEGA KV-27HS420 27" TV

1 Answer

High Pitch Sound From Samsung TXN3071WHF 30" TV

I think its the flyback and its starting to leak. this is a component responsible for the high voltage of your tv set. always observe safety in dealing with this. Have it check by a qualified technician. Good luck!

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