Re: Proscan PS56670 / Chassis CTC195 Issues

From: Andy (rowlandmcc_at_comcast.net)
Date: 08/18/04 

Date: 18 Aug 2004 16:20:38 -0700

Thanks for your response. I'll need to get a copy of the Service
Bulletins. Do you know where I can get a copy? Is there a website
that I can download them from?

I've since checked the heat sinks on the Convergence Power Supply and
the Module itself, and they are both cold. I static checked the
diodes and caps on the power supply and found them looking fine. I
checked voltages at the output connector of the PTV AUX board
(J19701), and the voltages are perfect for about 2 seconds, then they
all drop out except the +23V from the filament. This tells me the
"Current Limiting" is working, and there's probably something wrong on
the Convergence Module either over or under loading the power supply.
I couldn't tell which voltage was tripping the current limiting. I
think it was the -15V line going below -13V, and shutting the power
supply down.

I think your advice is very sound. I'll address all of the service
bulletins first, and see if that doesn't just take care of the
problem. If not, then I'll reassess. As far as my competence working
with SMD's goes, I've never done it, and it looks hard. But, I'm
pretty careful, and the learning factor is awesome, so I'll probably
just keep going until I either fix it, or it fixes me. >:| When it
comes time to replace the SMD's, I might just get intimidated enough
to let a professional do it.

BTW, in order to get the main board out of the TV, I need to
disconnect the High Voltage leads from the splitter, but I couldn't
figure out a way to do this. How is this done? I'm assuming that
they're probably soldered into the splitter, but are they soldered on
both ends?

Also, I got Chipper Check to display properly on an old computer. The
resolution was below what my new computer is capable of. Then I
figured out a way to get it to work on my new computer--in the
Advanced Settings.

Thanks again. If you have information on where I can get a copy of
the Service Bulletins, I'd really appreciate it.

Andy

"David" <dkuhajda@locl.net.spam> wrote in message news:<4122d7cd@news.greennet.net>...
> Your set has an onboard tuner and is not replaceable by itself. Odds are
> the set since it was made in 1997 has several service bulletins that need
> applied before doing any thing else.
>
> If the convergence power supply voltages are close, you have a problem on
> the convergence main board. Most likely a problem with the can shorting the
> 5v line to the convergence syscon (another service bulletin), or a problem
> with glue that has become conductive on either the 5v line or the clock and
> data lines, SDA,SCL.
>
> The tuner issues are also likely either a service bulletin or conductive
> glue under c15703and c15704, both surface mount capacitors will need
> removed, the solder and glue cleaned up, then replaced.
>
> Secondly, you cannot always reliably run Chipper Check on newer faster
> machines, you need to get a hold of an older, preferably slower than 333Mhz.
> Yes, you probably do need to change font size, etc. I am not sure your
> Chipper Check software version is tested 100% compatible with XP.
>
> You have multiple issues to address, start with the convergence issue first,
> Check ALL applicable service bulletins and apply all of them, then deal with
> the snowy picture issue.
>
> Be forewarned, if you are not 100% comfortable and competant working with
> tightly packed surface mount components and fully equipped with good
> soldering and desoldering equipment, odds that you will do more damage
> increase greatly. It is simply way too easy to damage surface mount stuff
> on that board, even pulling the thin board out carelessly can flex it enough
> to crack some surface mount parts!!!!
>
> David
>
> "Andy" <rowlandmcc@comcast.net> wrote in message
> news:76f40757.0408171626.129d3f45@posting.google.com...
> > I bought my Proscan 56" RPTV (model PS56670LG1, Chassis PTK195CP or
> > CTC195C) back in 1997. Within 6 months, I was experiencing
> > intermittent picture quality issues, such as the picture going to all
> > snow, and the audio making loud hissing/crackling sounds. Each
> > "event" would last approximately 1 minute, then the picture would
> > return to normal. I made the faulty assumption that I simply had
> > reception issues with my cable, and did not pursue a problem within
> > the TV itself. As a result, the problem has escalated into other
> > areas of the chassis. The picture is now very fuzzy, the convergence
> > is way out, and the picture is bowed at the top and bottom of the
> > screen.
> >
> > I am not a TV repairman, I'm an Engineer, but I used to repair TV's on
> > the side while I was in college, so I have a fundamental understanding
> > of electronic repair. I have the Chipper Check II system (ver 1.83a)
> > [which, by the way, is not displaying properly on my 1 year old
> > computer running XP - TCE says I have my fonts set incorrectly, but
> > every possible font size doesn't remedy the issue.] Chipper Check was
> > able to read the Main EEPROM without problem, the PIP Tuner EEPROM
> > without problem and supposedly, the Digicon EEPROM without
> > problem-although the Digicon EEPROM came back with all FF's in each
> > parameter.
> >
> > Also, during the I2C check, Chipper Check was able to communicate with
> > all components except it came back with the message: "Convergence
> > Module did NOT respond on the Run bus." [It also came back with the
> > message: "YPrPb Processor, U22303, did NOT respond on the Run bus."
> > But, I'm not certain that my chassis has the YPrPb Processor
> > installed--I was unable to find it.]
> >
> > From reading the many comments on this site regarding the CTC195
> > chassis, I measured the output voltage of the Convergence Power Supply
> > at the connector (J19701) and discovered the voltages were not as
> > published. The voltages at each pin were approximately 17 volts to
> > the ground pin (pin 3). I then pulled the Convergence Power Supply
> > connector and it did not effect the picture. I plugged the power
> > supply connector back in and the picture jumped a little bit, but did
> > nothing more.
> >
> > I don't know if the voltage errors are a result of some failure in the
> > convergence power supply, or the convergence module or both. I have a
> > copy of the "Basic Service Data" First Edition - First Printing dated
> > 1997. This was published long before the historical issues with this
> > chassis become known, so I have none of the Service Bulletins and
> > Service Kits later made available.
> >
> > I've noticed that many of you have extensive experience with this
> > chassis, and also that many of you have a great passion for your work,
> > so I'd love to hear your recommendations for repairing this TV.
> >
> > Thank you,
> >
> > Andy McClellan

Relevant Pages

  • Re: Proscan PS56670 / Chassis CTC195 Issues
    ... Convergence power supply and tuner are available ... > intermittent picture quality issues, such as the picture going to all ... I'm not certain that my chassis has the YPrPb Processor ... I measured the output voltage of the Convergence Power Supply ...
    (sci.electronics.repair)
  • Proscan PS56670 / Chassis CTC195 Issues
    ... intermittent picture quality issues, such as the picture going to all ... problem-although the Digicon EEPROM came back with all FF's in each ... I'm not certain that my chassis has the YPrPb Processor ... I measured the output voltage of the Convergence Power Supply ...
    (sci.electronics.repair)
  • Re: Publisher Clip Art
    ... Are you inserting the same picture every time? ... something you have downloaded from a web site? ... When you say your other bulletins are okay, ... insert art and it's fine. ...
    (microsoft.public.publisher)
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