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

  • From: "al m" <ampm@xxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Fri, 31 Jan 2003 12:08:19 -0500

Those cathode voltages seem low. Do you have a CRT checker?
al marquardt
ampm@xxxxxxx


----- 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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