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

From: "Damon" <damoneb@xxxxxxxxxxx>
To: <techassist@xxxxxxxxxxxxx>
Date: Fri, 22 Jul 2005 22:20:41 -0500
Do you have schematics? If so, one of the transistors driving or being
driven by the optoisolator can be jumpered (screwdriver) and maybe the unit
will start, I'm pretty sure that if that's the case, replacement of the
board will save you some time/money.

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


> After re-checking the power supply, I discovered that the chopper is not
os=
> 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=
> ing bad.
> I thought I would sub another chopper into it but I couldn't find any
cross=
>  for it.  I hate to order one and wait several days only find out that may
=
> not be it.
> Daryl=20
> 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 08:00:20 -0500
>
> >=20
> > 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
=
> way
> > to go on this unit.
> >=20
> > 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=
> ify
> > it was the smps, and it was not a "shorting" type of failure. The
oscilla=
> tor
> > just quits oscillating for no good reason. But in your case oscillation
> > isn't the issue, tranferring power to the secondary is......does the
final
> > output drive the transformer at all?
> >=20
> > 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
> >=20
> >=20
> > > 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=3D
> > > s.
> > > I do have power on the primary of the smps and does appear to be
> > oscillatin=3D
> > > g.
> > > I checked all of the semi's, resistors and electro's. I ohmed out the
> > switc=3D
> > > 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
> > >
> > >
> > >
> > > --=3D20
> > > ___________________________________________________________
> > > Sign-up for Ads Free at Mail.com
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> > >
> >
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References:
- [TechAssist] Re: RCA D52W20, ITC222, Convergence power supply problem
  - From: daryls_tv
[TechAssist] Re: RCA D52W20, ITC222, Convergence power supply problem

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