Tc-p42st30 making wierd buzzing noise the brighter set it the louder

[ricosavy]

I have a tc-p42st30 the tv makes a buzzing noise on the sc board i checked the screws and they are tight.Also the brighter the screen the louder the noise.Could it be something is getting to much voltage.i am gettin 220.05v on connector of sc.

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

Here is a pic

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

it is like something is causing interfernce look at red dots

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

On this one you can really see it

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

So is this a previously repaired SN board by the looks of the photos? 220V seems very high, how accurate is the meter? You could mark the trimpot on the PSU and note the current level, then try lowering the voltage.

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

https://www.badcaps.net/forum/showth...t=42680&page=2

post 31, 220v reported and adjusted down. SC board repaired, loose screws and buzzing

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

There are two pots one is vr251 on top and vr 261 .which should i adjust.in post says he thinks it is vr251 on top but he does not say which one he adjusts

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I adjusted it to 212 v looks lot better

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

He is picture after adjustment still here a little buzzing noise i guess it is normal panasonic to make it

[tom66]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

A little buzzing is normal.
Weird, another set with high Vs and odd picture problems, not seen that on older panels.
Usually high Vs just causes more power consumption, sometimes blue/green sparklies when way over rating.

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

There are two pots one is vr251 on top and vr 261 .which should i adjust.in post says he thinks it is vr251 on top but he does not say which one he adjusts

Hope you left VR261 alone.

It'd be interesting to know what these are meant to be and why they end up at 220V whether that's how it was or something has caused it to change?

I thought the A board controlled this now.

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I think it turned out pretty good i only paid $65 for it.thanks tw2005 for link.

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I did not touch vr261 just vr251 lowered to 212v there is where i could get the best picture.

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I did not touch vr261 just vr251 lowered to 212v there is where i could get the best picture.

Yeah, if i was to guess, i would think 210V would be in the ballpark.

Does have me suspicious with this being the second post with this issue. Can't help but think something is wrong. Wish I had measured the 50s30 I did. Hope it does not go this way. The old man will be pissed.

So was this fault straight after the SN board repair or was it fine and then suddenly went like this?

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I repaired the board and put it in it was like that it had the 14 blink error before repair.i believe the other tv had the same blink error on the link you posted.

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

Also i repaired a tc-p50s30 about 3 weeks ago np there same thing shorted sc board.which makes me think something else maybe wrong or it just goes high on tc-p42st30.

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

Also i repaired a tc-p50s30 about 3 weeks ago np there same thing shorted sc board.which makes me think something else maybe wrong or it just goes high on tc-p42st30.

I think it'd be worth investigatiing but with no schematics for these, would be difficult unless the design is similar to earlier generations, may be able to use that info.

Maybe when the Vsus gets shorted it does something? I'm really just hanging that one out there. It'd be interesting to swap over a PSU and also an A board to see but I guess you would not have bits laying around.

How many hours on this TV?

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

Have you tried serv mode and adjust vsus in menu low/high? It would be interesting to see if that still changes the voltage.

[ricosavy]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

I have not i will try see if i have any of these parts laying around.i did not go into service mode so i am not sure how may hrs.I do know that geek squad had done a calibration on the tv at least that is what previous owner said.

[tw2005]

Re: Tc-p42st30 making wierd buzzing noise the brighter set it the louder

Still interested to see if you can have a look at what vsus is set to in serv tool. i was looking at a schematic and saw Lo = 215v, Hi = 220v so would be handy to see if it's set to Lo but was punching out the 220v when it should be 215V. If set to high then probably should set to lo and adjust the PSu back. If it was lo, would also be nice to know if changing to Hi still increases volatage to 220.