[TechAssist] Re: FIXED Magnavox XS2552 C102, chassis 25P613-00AA, blows HOT immediately, need to know value of B+

  • From: "George" <grndmstrg@xxxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Sat, 22 May 2004 00:07:50 -0700

Phil, that was a good analogy of what might of happened. I might add 15,750
Hz, 60Hz was the old B&W standard long since changed to 15,734 Hz, 59.97 Hz
for color transmission and B&W with no chroma, this keeps the video & scans
synchronized to the 4.5 MHz subcarrier and minimizes crosstalk distortion,
not that it makes any difference here. Just my two cents worth, he-he.....

George
Afana Electronics
Moreno Valley, CA
----- Original Message -----
From: "Phil Bader" <tjanphyl@xxxxxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Friday, May 21, 2004 1:47 PM
Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis 25P613-00AA,
blows HOT immediately, need to know value of B+


> The H. output/fly circuit is a tuned L/C circuit. The "L" being for one, =
>
> the inductance of the fly windings. The "C" being tuning caps mainly.
> There must be resonance by a specific balance between the two, with=20
> resonance being the horiz. scan freq, 15750Hz. In some PC monitors that=20
> ran different horiz. scan freqs (15750hz, 35KHz,etc) they used relays,=20
> or later, switching FET's to switch in and out timing caps so  the L/C=20
> resonance would be maintained throughout the range of  H.  frequencies.  =
>
> By adding, or taking away tuning caps this was accomplished.
> In standard TV where one refresh rate is used, it's constant. A cap=20
> decreasing in value is like putting a smaller cap in, and detunes the=20
> circuit.
> Much like in RF power tranmitters with a "Pi" network coupling the final =
>
> RF output to the transmission/antenna system,this mis-match causes "SWR" =
>
> or standing waves, which can damage the final outputs. (in this case, HOT=
> )
> Thats how I understand it. Time to go home!
> Whew.
> Phil Bader
>
> Peter oliver wrote:
>
> >The way I understand it is that as the timing capacitor decreses in valu=
> e=20
> >the Frequency of the horz pulse increses (inverse relationship to the ou=
> tput=20
> >voltage). And since the Voltage developed in a Flyback circuit is partia=
> ly=20
> >developed by the timing of the circuit a higher frequncy devleoped by a =
> open=20
> >timing cap, yoke or coil anomomoly results in a higher operating voltage=
> =20
> >when that voltage exceeds the breakdown of another components a failure =
>
> >occurs. If I rember right that cap is directly off the collector of the =
> HOT=20
> >had one about a month ago that chared itself (had also caused a HOT fail=
> ure=20
> >the first time but the HOT I used was overrated enough to hold it). But =
>
> >being in that location it might also possibly help dispate some of the=20
> >inital pulse, I guess another way to describe the theory of operation as=
> =20
> >pretty much like a back EMF phenomina.
> >
> >Peter Oliver
> >Tucson Radio TV
> >
> >From: Kevin <kevintv@xxxxxxx>
> >Reply-To: techassist@xxxxxxxxxxxxx
> >To: techassist@xxxxxxxxxxxxx
> >Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis 25P613-00A=
> A,=20
> >blows HOT immediately, need to know value of B+
> >Date: Fri, 21 May 2004 12:29:58 -0700
> >
> >Nobody knows the answer, I guess.
> >
> >Kevin Wilks
> >Kevin's TV & Video Repair
> >Penticton BC Canada
> >kevintv@xxxxxxx
> >
> >
> >-----Original Message-----
> >From: techassist-bounce@xxxxxxxxxxxxx
> >[mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of becyn
> >Sent: Friday, May 21, 2004 10:31 AM
> >To: techassist@xxxxxxxxxxxxx
> >Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis
> >25P613-00AA, blows HOT immediately, need to know value of B+
> >
> >As Al said, I think you need to do some study on the theory of
> >operation. It
> >will help tremendously in you troubleshooting efforts.
> >
> >I have a saying that I use here; "You can't efficiently fix something
> >unless
> >you know how it works". Serendipity goes just so far...
> >
> >Jim McVey
> >McVey Alltronix
> >327 Broadway
> >Newburgh Ny 12550
> >ph: 845 561 8383
> >fx: 845 561 9017
> >Consumer electronics &
> >computer service.
> >Factory authorized for
> >over twenty brands.
> >----- Original Message -----
> >From: "Kevin" <kevintv@xxxxxxx>
> >To: <techassist@xxxxxxxxxxxxx>
> >Sent: Thursday, May 20, 2004 10:58 PM
> >Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis
> >25P613-00AA,
> >blows HOT immediately, need to know value of B+
> >
> >
> > > So the timing cap keeps the flyback primary pulse within the specs of=
>
> > > the HOT?  I have also had a bad connection on the timing cap and all
> > > that happened was the picture was affected.  Does whether the HOT is
> > > shorted or not depend on the design of the circuit?
> > >
> > > Kevin Wilks
> > > Kevin's TV & Video Repair
> > > Penticton BC Canada
> > > kevintv@xxxxxxx
> > >
> > >
> > > -----Original Message-----
> > > From: techassist-bounce@xxxxxxxxxxxxx
> > > [mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of becyn
> > > Sent: Thursday, May 20, 2004 3:34 PM
> > > To: techassist@xxxxxxxxxxxxx
> > > Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis
> > > 25P613-00AA, blows HOT immediately, need to know value of B+
> > >
> > > It will send the flyback primary pulse over the C-E 0r C-B ratings of=
>
> > > the
> > > H-out.(not to mention the timing skew)
> > >
> > > Jim McVey
> > > McVey Alltronix
> > > 327 Broadway
> > > Newburgh Ny 12550
> > > ph: 845 561 8383
> > > fx: 845 561 9017
> > > Consumer electronics &
> > > computer service.
> > > Factory authorized for
> > > over twenty brands.
> > > ----- Original Message -----
> > > From: "Kevin" <kevintv@xxxxxxx>
> > > To: <techassist@xxxxxxxxxxxxx>
> > > Sent: Thursday, May 20, 2004 5:47 PM
> > > Subject: [TechAssist] Re: FIXED Magnavox XS2552 C102, chassis
> > > 25P613-00AA,
> > > blows HOT immediately, need to know value of B+
> > >
> > >
> > > > Timing capacitor, C505 9.1 nF @ 1600 volts, was open (measured 20
> >pF).
> > > > I used C5149 for the HOT.  Thanks for all the replies.
> > > >
> > > > Why would this bad timing cap cause the HOT to short immediately
> >after
> > > > turning the set off?  Thanks.
> > > >
> > > > Kevin Wilks
> > > > Kevin's TV & Video Repair
> > > > Penticton BC Canada
> > > > kevintv@xxxxxxx
> > > >
> > > >
> > > > -----Original Message-----
> > > > From: techassist-bounce@xxxxxxxxxxxxx
> > > > [mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of
> > > gulftech@xxxxxxxx
> > > > Sent: Thursday, May 20, 2004 6:23 AM
> > > > To: techassist@xxxxxxxxxxxxx
> > > > Subject: [TechAssist] Re: Magnavox XS2552 C102, chassis 25P613-00AA=
> ,
> > > > blows HOT immediately, need to know value of B+
> > > >
> > > > Kevin,
> > > >
> > > > First, I don't like NTE or SK replacements, especially for HOT's.
> > > Next,
> > > > it is always best to start with the original.  If you don't have th=
> e
> > > > original, cross it to a generic with equal or better specs.  If you=
>
> > > > cross
> > > > it to an NTE and then try to use a generic that also crosses to the=
>
> > > same
> > > > NTE is not reliable.  The D1849 is a 7A, 120 wt, w/ damper.  The
> >NTE,
> > > is
> > > > lower gain and lower power rating (70 wt).  If you must use an NTE,=
>
> > > try
> > > > an NTE2318.
> > > >
> > > > Still, I am concerned about the HOT shorting immediately.  Check fo=
> r
> > > > open
> > > > safely caps in the horizontal deflection.  Often, you can see them
> > > > cracked and a little carbon burn on them.  This would cause you hig=
> h
> > > > voltage to run way high and take out the HOT.
> > > >
> > > > HTH,
> > > >
> > > >
> > > > Ken Smith
> > > > Gulf Technical Services
> > > > 3034 Gulf Breeze Parkway
> > > > Gulf Breeze, FL  32563
> > > > 850-934-8324 (Voice) 850-932-0819 (Fax)
> > > >
> > > >
> > > > On Wed, 19 May 2004 16:20:01 -0700 Kevin <kevintv@xxxxxxx> writes:
> > > > > I used a D1849 which crosses to an NTE 2353.  I don't have the
> >exact
> > > > > Phillips replacement.  I have done this before many times before
> > > > > with no
> > > > > call backs.  Even if the D1849 wasn't exactly the same as the
> > > > > Phillips
> > > > > part, it should be good enough for test purposes.  It should not
> > > > > fail in
> > > > > 1 second.  What, in your estimation, is the best generic sub for
> >NTE
> > > > > 2353?
> > > > >
> > > > > Kevin Wilks
> > > > > Kevin's TV & Video Repair
> > > > > Penticton BC Canada
> > > > > kevintv@xxxxxxx
> > > > >
> > > > >
> > > > > -----Original Message-----
> > > > > From: techassist-bounce@xxxxxxxxxxxxx
> > > > > [mailto:techassist-bounce@xxxxxxxxxxxxx] On Behalf Of
> > > > > gulftech@xxxxxxxx
> > > > > Sent: Wednesday, May 19, 2004 3:05 PM
> > > > > To: techassist@xxxxxxxxxxxxx
> > > > > Subject: [TechAssist] Re: Magnavox XS2552 C102, chassis
> >25P613-00AA,
> > > > > blows HOT immediately, need to know value of B+
> > > > >
> > > > > Kevin,
> > > > >
> > > > > Quit using those darn NTE outputs and buy a good stock of real
> > > > > transistors.  You end up beating yourself to death because of a
> >bad
> > > > > sub
> > > > > and think it's something else.  Costs you time, money, and
> >patience.
> > > > >
> > > > >
> > > > > Ken Smith
> > > > > Gulf Technical Services
> > > > > 3034 Gulf Breeze Parkway
> > > > > Gulf Breeze, FL  32563
> > > > > 850-934-8324 (Voice) 850-932-0819 (Fax)
> > > > >
> > > > >
> > > > > On Wed, 19 May 2004 12:49:10 -0700 Kevin <kevintv@xxxxxxx> writes=
> :
> > > > > > I measured the B+ before I installed the HOT by putting a 110
> >ohm,
> > > > > 30
> > > > > > watt resistor from collector to ground.  The B+ measured 127
> > > > > volts,
> > > > > > and
> > > > > > the STR30130 was ouputting 130.2 volts.  Thinking everything wa=
> s
> > > > > > good, I
> > > > > > installed the new HOT (Q502 NTE 2353) and turned the set on.
> >The
> > > > > HV
> > > > > > came up but 'sounded funny', so I quickly turned the TV off and=
>
> > > > > > discovered a totally black fuse and shorted HOT.  My flyback
> >rings
> > > > > > good.
> > > > > > Could it still be a bad flyback?
> > > > > >
> > > > > > Kevin Wilks
> > > > > > Kevin's TV & Video Repair
> > > > > > Penticton BC Canada
> > > > > > kevintv@xxxxxxx
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > >
> >------------------------------------------------------------------------=
>
> > > --
> > > ---
> > > > Lost Password:
> > > > http://www.tech-assist.org  and select "Login Problems?".
> > > > Email Archives:
> > > > //www.freelists.org/archives/techassist/
> > >
> > >
> > >
> > >
> >------------------------------------------------------------------------=
>
> > > -----
> > > Lost Password:
> > > http://www.tech-assist.org  and select "Login Problems?".
> > > Email Archives:
> > > //www.freelists.org/archives/techassist/
> > >
> > >
> > >
> >------------------------------------------------------------------------=
>
> >--
> >---
> > > Lost Password:
> > > http://www.tech-assist.org  and select "Login Problems?".
> > > Email Archives:
> > > //www.freelists.org/archives/techassist/
> > >
> >
> >
> >------------------------------------------------------------------------=
>
> >-----
> >Lost Password:
> >http://www.tech-assist.org  and select "Login Problems?".
> >Email Archives:
> >//www.freelists.org/archives/techassist/
> >
> >
> >------------------------------------------------------------------------=
> -----
> >Lost Password:
> >http://www.tech-assist.org  and select "Login Problems?".
> >Email Archives:
> >//www.freelists.org/archives/techassist/
> >
> >_________________________________________________________________
> >FREE pop-up blocking with the new MSN Toolbar =96 get it now!=20
> >http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
> >
> >
> >------------------------------------------------------------------------=
> -----
> >Lost Password:
> >http://www.tech-assist.org  and select "Login Problems?".
> >Email Archives:
> >//www.freelists.org/archives/techassist/
> >
> > =20
> >
>
> --=20
>
> Philip Bader
> Jan Phyl TV Inc. (estab. 1976)
> 3420 Recker Hwy. Winter Haven, Fl. 33880
> Fax (863) 299-8821
> email: tjanphyl@xxxxxxxxxxxxxxx
>
>
>
> --------------------------------------------------------------------------
---
> Lost Password:
> http://www.tech-assist.org  and select "Login Problems?".
> Email Archives:
> //www.freelists.org/archives/techassist/



-----------------------------------------------------------------------------
Lost Password:
http://www.tech-assist.org  and select "Login Problems?".
Email Archives:
//www.freelists.org/archives/techassist/

Other related posts:

  1. Home
  2. techassist
  3. Archive
  4. 05-2004