35" proscan problems (horizontal lines/turns off/high pitch whine)

Hi everyone. My friends and I got a 35" Proscan TV for free to
replace a broken Zenith 20" CRT (the picture is green and brigher
parts "bleed" over). I digress...in any case, the Proscan has
problems. When i turn it on, the green LED by the power button lights
up, but there is no image except for a few horizontal lines in the
middle of the screen than bend a little; it looks like |) rotated 90
degrees. After a second or so, the green led turns off and so does
the TV. When its doing this, there is a quiet high pitched whine.
Sometimes it will try to cycle on and off a few times before giving
up. Does anyone have any idea what's wrong? Can we use parts from
the 20" Zenith to fix this? I have soldering experience and basic
electronics repair skills.
Thanks!

 

You won't be able to repair it with basic skills.

 

Thanks for the vote of confidence. Seriously, does anyone have any
ideas what I can try? I have a multimeter and an oscilloscope. Its
going to be recycled if I cant fix it.
Thanks

 

I'm just being realistic. You need more than a scope, a meter and basic
skills.

 

Start here:

http://www.repairfaq.org/index.html

 

That's not necessarily true, gotta start somewhere, and CRT displays are
generally not too hard to work on. I don't have any specific advice for this
set, but I'd start by checking all the semiconductors in the horizontal
drive section as well as look for bulging electrolytic capacitors.

 

I rarely use anything more than a multimeter, basic troubleshooting skills,
and occasionally a tip from someone here. I've fixed dozens of TVs and
monitors over the years.

 

This part is what I had some trouble digesting:

quote: "Does anyone have any idea what's wrong? Can we use parts from
the 20" Zenith to fix this"
end quote

You in all your experience may think that these sets are "not to hard to
work on"

Not the case for the totally clueless.

 

That's not necessarily true, gotta start somewhere, and CRT displays are

The OP might be able to fix the set, but given the problem, as he describes
it, he'll probably need to shotgun a lot of components. And that's not the
way you usually fix things.

Without at least a comprehensive service manual, he's likely to have
trouble.

 

You might start by posting the model number and chassis number. If you want
a color by numbers fix you need to be more specific.

Leonard

 

Maybe just resolder the coils in the horizontal drive circuit...

Mark Z.

 

Ok, get back with the OP and tell him how to fix it.

 

the model number is PS35182 and the chassis is CTC170MA. Is there any
more information i can give?

Thanks

 

It is a CTC170 chassis.
Even an experienced technician with the service manual would have a
tough time with that one.

Do a google groups search for the CTC170 chassis and see what comes
up.

Before you toss the set, find out if any repair shops are willing to
pick it up for free.

 

Did a google search and found this site:
http://wa6ati.com/CTC170-171.html

more specifically:
Proscan PS35682 CTC170 cycling on an off CTC170 chassis. Unit will
cycle on and off three times then finally shut off. Gave tech
instructions relating to the this type of shut down complaint. The 9
volt source was OK. The 3.7 volts that must be on pin 2 of U3101 (CPU)
never rose above .8 volts. These two voltages are critical to the
operation of the D.C. detect circuit. Problem was U1902 audio output
IC on audio board.

Does anyone know where I can get circuit diagrams for the set?
Thanks