[TechAssist] Re: RCA model # F32683SB, CTC197CE2,dead, relay clicks.

  • From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Mon, 27 Jan 2003 17:05:18 -0600

Excellent point Leonard.  An active test is better than a passive test.  In
the CTC19x series I have seen many IHVTs that just don't break down untill
you pass a couple hundred volt peaks.  If you have an external power supply,
say 30v + and a drive signal you are good to go.  The Sencore built it stuff
only goes up to about 15vdc and that is not enough to break down the
transformer.

I have a digital storage o'scope so it is easier for me to see the ringing
on an IHVT however here is how to do it with an analog scope.

1.  Set the scope on "Normal Trigger"--not automatic, which most techs use.
2.  Set the scope on about 20 uS.
3.  Set the scope to trigger on about 200v. (if you are on the collector of
the output transistor)
    a.  If you can not scope the HOT collector directly use a secondary,
such as the 200v supply
    b.  set the scope to trigger on about 15-20% of the peak pulse you would
expect there.
4.  Turn the intensity of the trace up.
5.  Hit the power button while watching the scope.

What you will see if the IHVT is bad is a series of pulses decaying in
amplitude.

Wayne Vanaman
Omega Electronics
6904 W Fairfield Dr
Pensacola, Fl.  32506-3310

Wayne@xxxxxxxxxxxxxxxxxxxxx
WWW.PensacolaTVRepair.Com

850-456-5995 voice
850-458-6369 fax


----- Original Message -----
From: "Leonard G. Caillouet" <lcaillo@xxxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Sent: Monday, January 27, 2003 4:47 PM
Subject: [TechAssist] Re: RCA model # F32683SB, CTC197CE2,dead, relay
clicks.


>
> Some flybacks will ring good with these tests and still be bad.  The best
> test that I have found is the Sencore drive test on the TVA92 which is
just
> a 25v horizontal key pulse applied to the primary. You measure the dc
output
> on the anode lead and compare to the chart.  It is very effective at
> identifying HV rectifier problems that ringing will not.
>
> Leonard G. Caillouet
> Service Manager
> Electronics World
> Gainesville, FL
> 352-332-5608
> 352-332-5668 (fax)
>
>
> ----- Original Message -----
> From: "Wayne Vanaman" <Wayne@xxxxxxxxxxxxxxxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Monday, January 27, 2003 4:32 PM
> Subject: [TechAssist] Re: RCA model # F32683SB, CTC197CE2,dead, relay
> clicks.
>
>
> >
> > The ringing test is only that, a test.  The information is neither good
> nor
> > bad by itself.  A good/bad test means nothing.  The Sencore VG91,
HA2500,
> > and LC102 will all tell you that the IHVT is good because they have
> > arbitrarily selected 12 or something as the good/bad cut off.  You need
to
> > know what the "new" or "good" ihvts measure.
> >
> > The best test for these is to see them ring would you hit the power
> button.
> >
> > Here are some readings I recorded:
> >
> >
> >
> > IHVT 237506 2 good units measured.
> > Pins 2-3 ring 57, 54 on the z-meter. Measures 2.77, 2.85 mH
> > Pins 1-2 ring 29, 25 and measures 1.49, 1.43 uH
> > Pins 1-3 ring 57, 54 and measures 2.52, 2.64 mH
> > Pins 6-10 ring 48, 41 and measures 530, 540 uH
> > On the TVA
> > Pins 1-3 ring 30, 31
> > Pins 1-2 ring 14, 16
> > Pins 2-3 ring 30, 32
> > Pins 6-10 ring 36, 36
> >
> > Pin 5-anode leaks 2 mA
> >
> > BAD UNITs z-meter
> > pins 2-3 ring 19, 40
> > pins 1-2 ring 2, 17
> > pins 1-3 ring 18, 39
> > pins 6-10 ring 7, 30
> > On the TVA
> > Pins 2-3 ring 15, 27
> > Pins 1-2 ring 0, 11
> > Pins 1-3 ring 14, 26
> > Pins 6-10 ring 0, 26
> >
> >
> > Notice the relatively high (good) ring count on the defective units.
> >
> >
> >
> >
> > Wayne Vanaman
> > Omega Electronics
> > 6904 W Fairfield Dr
> > Pensacola, Fl.  32506-3310
> >
> > Wayne@xxxxxxxxxxxxxxxxxxxxx
> > WWW.PensacolaTVRepair.Com
> >
> > 850-456-5995 voice
> > 850-458-6369 fax
> >
> >
> > ----- Original Message -----
> > From: "Kevin" <kevintv@xxxxxxx>
> > To: <techassist@xxxxxxxxxxxxx>
> > Sent: Monday, January 27, 2003 3:05 PM
> > Subject: [TechAssist] Re: RCA model # F32683SB, CTC197CE2,dead, relay
> > clicks.
> >
> >
> > >
> > > Which pins do I use to ring the flyback?  I have the schematic but I
> > > can't find pin 14 on the flyback.  Pins 2 and 3, and 1 and 3 rang
good.
> > > Pins 1 and 2 rang bad.
> > >
> > > 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 Jim Myers
> > > Sent: Monday, January 27, 2003 4:22 AM
> > > To: techassist@xxxxxxxxxxxxx
> > > Subject: [TechAssist] Re: RCA model # F32683SB, CTC197CE2,dead, relay
> > > clicks.
> > >
> > >
> > > Bad flyback, pull it and ring test it to be sure.
> > > ----- Original Message -----
> > > From: "Kevin" <kevintv@xxxxxxx>
> > > To: "TECH-ASSIST" <techassist@xxxxxxxxxxxxx>
> > > Sent: Monday, January 27, 2003 4:08 AM
> > > Subject: [TechAssist] RCA model # F32683SB, CTC197CE2,dead, relay
> > > clicks.
> > >
> > >
> > > Hi fellow techs,
> > >
> > > Working on this 32" RCA.  When the pwr switch is pressed the just
> > > clicks-no HV or sound.  Only brought in chassis-nojig either.  Any
ideas
> > > what could be wrong?  I have never seen this chassis before so any
help
> > > would be appreciated.  TIA
> > >
> > > Kevin Wilks
> > > Kevin's TV & Video Repair
> > > Penticton BC Canada
> > > kevintv@xxxxxxx
> > >
> > >
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