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Re: Quick Question about power supply high pitch noise
That noise should not be normal unless it was there from its new condition. That noise seems to be there when the circuit is demanding higher current from the power supply and the transformer is trying to keep up with the demand.
How many capacitors did you replace?
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Aug 23, 2013 - Uploaded by ShopJimmy.com
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Usually out of tolerance capacitors, resistors going high, and leaky diodes in the switchmode power supply can cause a high pitched squeal from any TV. Occasionally a bad transformer winding on the same board can also cause the noise but can also be a deflection fault. Check the PSU board for any bulging or dodgy looking electrolytics first then proceed from there. If you have a multimeter, you can measure the diodes and resistors. Before going any further, and worrying about repair costs, do some simple checks first. You may end up needing a replacement PSU PCB for the model of TV you have; a refurbished board is cheaper than a new one and if you fit it yourself, you save on labour costs. Start with the power supply board and work from there.
The high-pitched squeal is from the power supply, usually because of failure of the horizontal output transistor, flyback transformer, or both. Without a specific model I can't give more definite information about part numbers or likely costs. But repairs of this type usually have parts costs in the 10 to 75 dollar range (depending on just which parts are bad, and where replacements come from) plus whatever labor costs the repairer charges.
the high pitch squeal indicates shorted component/s. the transformer goes hot co'z its being overloaded by the shorted component, it too could be the one creating the squeal!!
if you have experience with electronic troubleshooting, try to test some of the components particularly on the secondary part of the transformer. Be careful and make sure the TV set is unplugged. test for shorted diodes and transistors, if you're in doubt of your readings try to desoldering one leg of the diode then proceed with the testing/measuring. replace any of the bad components you find exactly with same part number or replacements with the same rating.
spend more time on it resoldering some other cold soldered components.
I have never heard a tube make noise when there is a good picture. Anyway, the noise has to be a transformer ringing or oscilating. They make a high pitched squeal when they have a loose winding or their cover is loose. You probably won't be able to feel or see anything loose on these transformers The power supply switching transformer is the first to look at. Take a hot glue gun and just cover the thing...especially at the base of it. The next (and only other) one is the horizontal drive transformer.It is located close to the high voltage transformer( biggest thing on board and usually in back or corner of the PCB.This one wont squeal) The horizontal drive transformer is about the size of a large marble and is encased in a black plastic cover. Cover it with hot glue also.
If you take the back off you will probably be able to localize where the squeal is coming from. You will probably need a signal to hear the noise also. After you find where it is coming from UNPLUG the set before doing any hot gluing!!!!
If you 're not up to this procedure take it to a technician. Your tube is not going bad and the set is definitly worth repair. Simple fix!! Good Luck!!
I had the same issue. The tech that came out today removed the transformer on the power supply board, "resealed" it, and replaced it (re-soldered the same part back on) -- the transformer apparently vibrates because it was not properly sealed. BTW, mine was about the fifteenth that he has performed this repair on within the past couple of months -- all 32" and 26" Samsungs. Now, it appears to be absolutely silent.
It always nice when the high-voltage circuit gives you fair warning of
impending doom. Have the high-voltage (flyback) transformer
replaced now before it fails catastrophically and wipes out other stuff with it. There are other things that could make noise too, same advice applies to them.
Hope ya fix it!