[TechAssist] Re: Samsung TV, model TXJ2554 chassis K51A -black screen SAMS 4256

There is no load on the 200v line with no video,  thats why the collectors
of RGB are high.   vertical problems can also cause this problem because of
the way it blanks video even though you may have deflection.   However I
have had  a unit with black screen no video caused by the Jungle IC on the J
model

Phillip R Hull     STET
phil245@xxxxxxxxxxxxx
----- Original Message -----
From: "Gary McCartney" <gary@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Friday, January 31, 2003 11:58 AM
Subject: [TechAssist] Re: Samsung TV, model TXJ2554 chassis K51A -black
screen SAMS 4256


>
> Yes, the 200V line checks in at 206V. Even replaced the filter caps on
> the line but didn't help.
>
>
>
>
> Gary McCartney
>
> McCartney Electronics
> 7134 Fife Rd, RR 7
> Guelph Ontario Canada N1H 6J4
> Fax: (519)821-1530
> email: gary (at) number63.ca
>
>
>
>
>
>
>
> al m wrote:
> >
> > Looks like your cathode voltage is too low too. Did you check your 200V
> > line.
> > al marquardt
> > ampm@xxxxxxx
> >
> > ----- Original Message -----
> > From: "Damon" <DAMON101@xxxxxxxxxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Friday, January 31, 2003 7:36 AM
> > Subject: [TechAssist] Re: Samsung TV, model TXJ2554 chassis K51A -black
> > screen SAMS 4256
> >
> > >
> > > I get a feeling ( 8-0).....that your screen control is messing with
your
> > > cathode voltage. and this unit I believe has IK feedback.
> > > Yeah your screen voltage is too low, isn't there a boosted supply tied
> > into
> > > the screen control circuit on this? If so, check it. (You have
schematics,
> > > right?) If not, then the IHVT will need replacement.
> > >
> > > Damon Brunger
> > > Telrad Electronic Services
> > > Ft Wayne, IN 46815
> > > ----- Original Message -----
> > > From: "Gary McCartney" <gary@xxxxxxxxxxx>
> > > To: <techassist@xxxxxxxxxxxxx>
> > > Sent: Thursday, January 30, 2003 2:32 PM
> > > Subject: [TechAssist] Samsung TV, model TXJ2554 chassis K51A -black
screen
> > > SAMS 4256
> > >
> > >
> > > >
> > > > This is a Samsung TXJ2554 chassis K51A. (SAMS 4256)
> > > > Turn set on, has sound but screen is black. Let it run and
> > > > nothing changes usually, but one time the picture popped on normal
all
> > > > of a sudden. When turned on the next time, it had a black screen
only
> > > > again.
> > > > I turned the screen control all the way up and the picture
> > > > snapped in ok. Turned screen back down and the picture bloomed like
> > > > crazy.
> > > > It went really bright like it was saturated with too much contrast.
> > > > Turned it back up to max. and picture was ok.
> > > > Measured G2 on CRT board. Had an even voltage range but seems low-
went
> > > > from 76V low end to 276V high end. Disconnected CRT board and G2
voltage
> > > > acted the same. Then I changed the G2 disc capacitor on the CRT
board
> > > > (.01uF 3kv). That didn't make any difference. I think flyback should
put
> > > > out around 500V on G2 at high
> > > > end on most TVs, but it is only 276V. Is flyback defective?  Would
The
> > > > blooming be a sour tube? Why would it bloom  when I turn the screen
> > > > down? Tapping on the tube neck doesn't make anything happen. R,G, B
> > > > cathodes measure around 68Vdc with normal picture (seems low, ?).
With
> > > > blooming picture, I measure 33Vdc. With CRT socket removed, I read
> > > > 191Vdc. The G1 pin measures approx. 0.4Vdc in any condition. So from
> > > > these measurements it looks as if the CRT is drawing too much
current.
> > > >
> > > >
> > > > Do I have a bad flyback or CRT, or both?  Does anyone have a
schematic
> > > > with the dc voltages so I know if my readings are anywhere close to
> > > > normal- which I don't believe they are?
> > > > --
> > > >
> > > >
> > > >
> > > >
> > > > Gary McCartney
> > > >
> > > > McCartney Electronics
> > > > 7134 Fife Rd, RR 7
> > > > Guelph Ontario Canada N1H 6J4
> > > > Fax: (519)821-1530
> > > > email: gary (at) number63.ca
> > > >
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> --
>
>
>
>
> Gary McCartney
>
> McCartney Electronics
> 7134 Fife Rd, RR 7
> Guelph Ontario Canada N1H 6J4
> Fax: (519)821-1530
> email: gary (at) number63.ca
>
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