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

  • From: "J Silverman" <greentron@xxxxxxx>
  • To: <techassist@xxxxxxxxxxxxx>
  • Date: Thu, 4 Aug 2005 13:31:36 -0400

Last group I purchased was from Digi-Key. They had other tv chips at very
good prices too.
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: Thursday, August 04, 2005 1:19 PM
Subject: [TechAssist] Re: RCA D52W20, ITC222, Convergence power supply
problem


> 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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