[TechAssist] Re: RCA D52W20, ITC222, Convergence power supply problem

  • From: gulftech@xxxxxxxx
  • To: techassist@xxxxxxxxxxxxx
  • Date: Thu, 4 Aug 2005 12:19:32 -0500

Jerry,

Where can you buy them that cheaply?  I used to buy them at Electro Sound
for 60 cents each, but they have been out of them for over three years. 
A check of Tritronics shows them anywhere from $1.50 to $10.00.  Most are
about $5.00.  Even the TT-TLP621G is $1.49 each, or $1.29 for 50 or more.
 Sorry, if it has "TT" on it, I won't buy it at all.


Ken Smith
Gulf Technical Services
3034 Gulf Breeze Parkway
Gulf Breeze, FL  32563
850-934-8324 (Voice) 850-932-0819 (Fax)

On Tue, 26 Jul 2005 11:57:53 -0400 "J Silverman" <greentron@xxxxxxx>
writes:
> If you buy generic ones in bulk they are only about $0.50 so it costs 
> more
> to test than to replace. Costs a little less to test in circuit 
> rather than
> removing.
> Jerry Silverman
> Greentron Inc
> 4 Newland Ave
> Greenville SC 29609
> Fax/Phone 864 232 3889
> mail to: greentron@xxxxxxx
> ----- Original Message -----
> From: <gulftech@xxxxxxxx>
> To: <techassist@xxxxxxxxxxxxx>
> Sent: Tuesday, July 26, 2005 10:07 AM
> Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence power 
> supply
> problem
> 
> 
> > Jerry,
> >
> > That is a truly outstanding suggestion.  I have often wondered how 
> I
> > could check an opto-isolator, but usually just replaced them if I 
> had any
> > doubts.  Bet I've replaced lots needlessly.
> >
> > May try to build a test jig with a socket, battery, limiting 
> resistor,
> > and posts for a meter.
> >
> > You have helped many techs with that suggestion.
> >
> > Thank you,
> >
> >
> > Ken Smith
> > Gulf Technical Services
> > 3034 Gulf Breeze Parkway
> > Gulf Breeze, FL  32563
> > 850-934-8324 (Voice) 850-932-0819 (Fax)
> >
> >
> > On Sat, 23 Jul 2005 14:28:31 -0400 "J Silverman" 
> <greentron@xxxxxxx>
> > writes:
> > > That sound normal to me! If you put some current into pins 1 and 
> 2,
> > > say from
> > > an ohm meter, then you should see some ohms appear at terminals 
> 3
> > > and 4, if
> > > your meters have the right polarity.
> > > Jerry Silverman
> > > Greentron Inc
> > > 4 Newland Ave
> > > Greenville SC 29609
> > > Fax/Phone 864 232 3889
> > > mail to: greentron@xxxxxxx
> > > ----- Original Message -----
> > > From: <daryls_tv@xxxxxxx>
> > > To: <techassist@xxxxxxxxxxxxx>
> > > Sent: Saturday, July 23, 2005 1:20 AM
> > > Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence power
> > > supply
> > > problem
> > >
> > >
> > > > No... I don't have any schematics on this set.
> > > > I think I may have found the problem.  I have absolutly no
> > > resistance
> > > readi=
> > > > ngs between pins 3 & 4 of the opt-coupler, even on high meg 
> scale.
> > > > I will post the results when the part comes in.
> > > > Thanks,
> > > > Daryl
> > > > Daryl's TV
> > > > 2402 Wyoming Ave.
> > > > El Paso, TX  79903
> > > > 915-565-9184 Voice/Fax
> > > > daryls_tv@xxxxxxx
> > > > www.angelfire.com/tv2/daryls_tv
> > > >
> > > > ----- Original Message -----
> > > > From: Damon <damoneb@xxxxxxxxxxx>
> > > > To: techassist@xxxxxxxxxxxxx
> > > > Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence 
> power
> > > supply
> > > prob=
> > > > lem
> > > > Date: Fri, 22 Jul 2005 22:20:41 -0500
> > > >
> > > > >=20
> > > > > Do you have schematics? If so, one of the transistors 
> driving or
> > > being
> > > > > driven by the optoisolator can be jumpered (screwdriver) and
> > > maybe the
> > > un=
> > > > it
> > > > > will start, I'm pretty sure that if that's the case, 
> replacement
> > > of the
> > > > > board will save you some time/money.
> > > > >=20
> > > > > Damon B
> > > > > Telrad Electronics
> > > > > Fort Wayne IN
> > > > > ----- Original Message -----
> > > > > From: <daryls_tv@xxxxxxx>
> > > > > To: <techassist@xxxxxxxxxxxxx>
> > > > > Sent: Friday, July 22, 2005 1:10 PM
> > > > > Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence 
> power
> > > supply
> > > > > problem
> > > > >=20
> > > > >=20
> > > > > > After re-checking the power supply, I discovered that the
> > > chopper is
> > > not
> > > > > os=3D
> > > > > > cillating.  I guess I was in a hurry and used the wrong 
> ground
> > > as
> > > > > reference.
> > > > > > I rechecked every component on the primary side and still 
> not
> > > finding
> > > > > anyth=3D
> > > > > > ing bad.
> > > > > > I thought I would sub another chopper into it but I 
> couldn't
> > > find any
> > > > > cross=3D
> > > > > >  for it.  I hate to order one and wait several days only 
> find
> > > out that
> > > =
> > > > may
> > > > > =3D
> > > > > > not be it.
> > > > > > Daryl=3D20
> > > > > > Daryl's TV
> > > > > > 2402 Wyoming Ave.
> > > > > > El Paso, TX  79903
> > > > > > 915-565-9184 Voice/Fax
> > > > > > daryls_tv@xxxxxxx
> > > > > > www.angelfire.com/tv2/daryls_tv
> > > > > >
> > > > > >
> > > > > > ----- Original Message -----
> > > > > > From: Damon <damoneb@xxxxxxxxxxx>
> > > > > > To: techassist@xxxxxxxxxxxxx
> > > > > > Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence
> > > power supply
> > > > > prob=3D
> > > > > > lem
> > > > > > Date: Fri, 22 Jul 2005 08:00:20 -0500
> > > > > >
> > > > > > >=3D20
> > > > > > > Daryl,
> > > > > > > I have yet to see a defective convergence power supply 
> on
> > > the ITC
> > > 222,
> > > > > > > HOWEVER.....
> > > > > > > The CTC 195/197 series has had intermittant conv power
> > > shutdown, and
> > > =
> > > > the
> > > > > > > board cost was cheap enough to just replace it entirely. 
> It
> > > might be
> > > =
> > > > the
> > > > > =3D
> > > > > > way
> > > > > > > to go on this unit.
> > > > > > >=3D20
> > > > > > > On the boards I worked on, I was able to eventually see 
> it
> > > fail,
> > > then=
> > > >  by
> > > > > > > jumpering  two leads on the primary side I was able to
> > > restart it
> > > and
> > > > > ver=3D
> > > > > > ify
> > > > > > > it was the smps, and it was not a "shorting" type of
> > > failure. The
> > > > > oscilla=3D
> > > > > > tor
> > > > > > > just quits oscillating for no good reason. But in your 
> case
> > > oscillati=
> > > > on
> > > > > > > isn't the issue, tranferring power to the secondary
> > > is......does the
> > > > > final
> > > > > > > output drive the transformer at all?
> > > > > > >=3D20
> > > > > > > Damon B
> > > > > > > Telrad Electronics
> > > > > > > Fort Wayne IN
> > > > > > > ----- Original Message -----
> > > > > > > From: <daryls_tv@xxxxxxx>
> > > > > > > To: <TechAssist@xxxxxxxxxxxxx>
> > > > > > > Sent: Thursday, July 21, 2005 6:18 PM
> > > > > > > Subject: [TechAssist] RCA D52W20, ITC222, Convergence 
> power
> > > supply
> > > > > problem
> > > > > > >=3D20
> > > > > > >=3D20
> > > > > > > > RCA D52W20, ITC222, Convergence power supply problem
> > > > > > > >
> > > > > > > > Another looser here.
> > > > > > > > Customer claims they changed channels and lost the
> > > convergence.
> > > > > > > > What I found is no control of convergence and a 
> distorted
> > > picture.
> > > > > > > > There are no voltages out of the convergence power 
> supply
> > > on the
> > > > > > > secondarie=3D3D
> > > > > > > > s.
> > > > > > > > I do have power on the primary of the smps and does 
> appear
> > > to be
> > > > > > > oscillatin=3D3D
> > > > > > > > g.
> > > > > > > > I checked all of the semi's, resistors and electro's. 
> I
> > > ohmed out
> > > t=
> > > > he
> > > > > > > switc=3D3D
> > > > > > > > h mode power transformer. I didn't find any bad
> > > components.
> > > > > > > > I hope someone has encountered this before and can 
> give a
> > > few
> > > > > pointers.
> > > > > > > > Thanks,
> > > > > > > > Daryl
> > > > > > > > Daryl's TV
> > > > > > > > 2402 Wyoming Ave.
> > > > > > > > El Paso, TX  79903
> > > > > > > > 915-565-9184 Voice/Fax
> > > > > > > > daryls_tv@xxxxxxx
> > > > > > > > www.angelfire.com/tv2/daryls_tv
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > --=3D3D20
> > > > > > > >
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