ps50q96hd no picture

[wreksta]

another plasma

this one has no picture at all power I presume works atm
the ymain has a light on it this indicates a fault doesn't it?

have disconnected both x and y but still no picture
with the x and y disconnected the tcon control board led flashed every second as its supposed to but with x and y connected the control boards led is fully lit

any ideas

[tom66]

Re: ps50q96hd no picture

Yes y-main LED indicates fault.
Check y-buffers for burnt IC and y-main for burnt mosfets, resistors and zeners
Also check y-main capacitor 100uF/50V can fail near Vs power connector

[tom66]

Re: ps50q96hd no picture

Panel manuals maybe? For Philips but same panel as this Samsung I believe.

[wreksta]

Re: ps50q96hd no picture

Yes y-main LED indicates fault.
Check y-buffers for burnt IC and y-main for burnt mosfets, resistors and zeners
Also check y-main capacitor 100uF/50V can fail near Vs power connector

tom nothing burned or bown
should I just change that cap the on on the ymain is not bulging or anything also
could power board cause this I get 205 at vs on the y so ive proberbly answered my own question

[wreksta]

Re: ps50q96hd no picture

changed cap still the same anything else to look out for

[tom66]

Re: ps50q96hd no picture

Check all semiconductors for shorts, check buffer board

[wreksta]

Re: ps50q96hd no picture

want to give me a clue on how to test semi conductors mate im earning slowly lol

buffers are they the lower boards or the ones directly connected to the y main

[tom66]

Re: ps50q96hd no picture

Just check for shorts on semiconductors. There are plenty of tutorials on the internet, just google "test mosfet for shorts" etc. Buffers are connected to y-main. Also check -Vsc voltage.

[wreksta]

Re: ps50q96hd no picture

tom theres no test point for that

ive tested ve and vs both are dead on

[tom66]

Re: ps50q96hd no picture

If you provided some pictures of the Y-main it may help.

[wreksta]

Re: ps50q96hd no picture

will do tom heres a thing I only have 14-15v on ve
what causes this

[tom66]

Re: ps50q96hd no picture

You probably also have low -Vsc due to short somewhere. How about a picture?

[wreksta]

Re: ps50q96hd no picture

have added pictures of everything










this cap near lower buffer connection looks a little funny due to someone incorrectly fitting it and ruinng the via so I took it to the closest positive point in track

[tom66]

Re: ps50q96hd no picture

"SD" cap is not low ESR and may cause problems.

Any chance of a higher detail picture of the Y-main board? I want to be able to see any test points visible.

[wreksta]

Re: ps50q96hd no picture

tom after testing allsorts lol

disconnected y from buffers still the same so buffers seem ok not heating up etc

disconnected x main and problem still exists

I finally found the vscan adj and test point

so my findings are the when tv first powered I get 195 as on the panel sticker but soon as I get the green led on y main voltageon vscan drops all the way to 0.0

[tom66]

Re: ps50q96hd no picture

That is normal if there is a fault -- you need to track down why the LED is lighting up -- would suggest checking Vset and +Vsch (if available.)

[wreksta]

Re: ps50q96hd no picture

cant find test points or any of those mate just the adjusters

they are long yfr
an long yset

need a dummies guide for mosfet testing the ones on the heatsink
can I test them in circuit or need to remove

also the cap nr the fuse top right of y main what the values I believe this one been changed for a diff type as looks rather large
and the one I modify to lie down


also forgot to add should the tv power up as soon as plug is plugged in this is without hitting power button or stnby on remote as this set does

[tom66]

Re: ps50q96hd no picture

These models do power on automatically that is fine.

MOSFET testing: http://www.4qdtec.com/mostest.html

Mostly, they can be left in circuit.

You have not yet provided a larger image of the Y-main so I can't advise on any poorly labelled test points etc.

The cap near the top of the board is 100uF/50V or 470uF/25V they changed it middle of the design I believe.

[wreksta]

Re: ps50q96hd no picture

These models do power on automatically that is fine.


The cap near the top of the board is 100uF/50V or 470uF/25V they changed it middle of the design I believe.

tom the last person that messed with this has a 1000uf 35v this is one right nr ymain power connector and fuse


would this be bad

[wreksta]

Re: ps50q96hd no picture

also will post pic of ymain il do it in so the board is photographed via 4 sections