RCA TV turning off and on

[Matt]

I own an RCA 27" console TV, Model #: G27220TN, Chasis: CTC169CA that was
Manf. on 8/1991. I am having problems when I turn it on, the green light on
the front comes on for about a second, and before the picture comes up, it
shuts itself back off. Then it goes into a cycle of shutting on and off
about once per second, and can last up to 5 minutes before it finally comes
on and stays on. During this period there is a squiggly white line that
shows up on the screen each time it comes on. I did some initial googling
and found that the on/off problem seems to be common among older RCA
televisions, and I am wondering if it is worth repair or if maybe I could
even fix it myself. I noticed a few posts talking about loose solder
connections, in which case if I knew what to check I could probably
re-solder. I know nothing about tv repair, other than don't open it unless
it's been unplugged for 48hrs. This is not a primary TV, so it is really
not a big deal, I'm just curious what I'm looking at for a repair bill. If
it is more than say $50-100, it's really not worth it (I only paid $100 for
it in the first place). But if I could re-solder some connections and get
it back in shape, I would definately try that. Anyone know what is causing
this?

Also, anyone know where I could find some documentation or guides for
repairing this model? Or any safety precautions?

Thanks for any help,
Matt

 

[Tom MacIntyre]

I own an RCA 27" console TV, Model #: G27220TN, Chasis: CTC169CA that was
Manf. on 8/1991. I am having problems when I turn it on, the green light on
the front comes on for about a second, and before the picture comes up, it
shuts itself back off. Then it goes into a cycle of shutting on and off
about once per second, and can last up to 5 minutes before it finally comes
on and stays on. During this period there is a squiggly white line that
shows up on the screen each time it comes on. I did some initial googling
and found that the on/off problem seems to be common among older RCA
televisions, and I am wondering if it is worth repair or if maybe I could
even fix it myself. I noticed a few posts talking about loose solder
connections, in which case if I knew what to check I could probably
re-solder. I know nothing about tv repair, other than don't open it unless
it's been unplugged for 48hrs. This is not a primary TV, so it is really
not a big deal, I'm just curious what I'm looking at for a repair bill. If
it is more than say $50-100, it's really not worth it (I only paid $100 for
it in the first place). But if I could re-solder some connections and get
it back in shape, I would definately try that. Anyone know what is causing
this?

The CTC 169 is/was a very good chassis. It's getting old, but may be
worth repairing. Was the picture/sound good before the problem? Does
it have at least some of the features you want? It is also very
particular about how it is treated during troubleshooting, like most
complicated electronics equipment. Experienced technicians who see
these for the first time have problems, so you shouldn't try it
yourself.

Also, anyone know where I could find some documentation or guides for
repairing this model? Or any safety precautions?

Do a Google search...if you don't decide to fix it, may I suggest that
you give it to someone who will, or donate it to a shop...keep it out
of the landfill.

Tom

 

[Lance Dyer]

bad caps in power supply esr meter will find them

 

[wolfhedd]

if you look under the board you can look for cold solder joints, you will
see a ring wher the solder is loding connection, and a screwdriver whack
will usually cycle these connections, but it almost sounds like a component
that is going out of tolerance, to find this out you can take a heat gun, or
hair dryer, and without frying anything, after you let the set cool off for
a 1/2 hour after trying to turn it on, you can heat the whole board up when
it is warm, just see if it turns on and stays on the first time then. if
so, then you need to heat up only section at a time, and try it again, then
you can narrow it down to one component this way, this will help diagnose
the problem, but then you will need some decent meters to check those
components afterwords like esr meter which can be difficult for an amateur
at times.
wolf

 

[Jason D.]

bad caps in power supply esr meter will find them


on

Most number 1: How good the picture quality? If still nice, it is
worth fixing.

The 169'ers is excellent chassis but *tricky* one for unfamillar.

Now on this "rebooting itself", it is either barely bad diode
location: CR4118 (use 243636 RCA part number). Or HV shutdown cutting
in and out. Vertical problems doesn't make it shut down, this circuit
is enabled for projector which will trip the shutdown, on direct view
CRT it will give you a straight horizontal line not wavy line.

The switching power supply is 100% duty whatever tv is on or off.
Means those four electrolytic capacitors in the hot side will be a
problem except they usually cause TV not to start or too high B+ in
standby. Change those four caps. There is small cap that smoothes
out ripple for the horizontal transformer supply. 47uF 50V I think.

RCA boards are best soldered with adjustable soldering irons set for
550F for light to medium joints, for heavy ones set to 600F. Too
much heat lifts the traces/pads.

Cheers,

Wizard

 

[Chaos Master]

Matt posted in sci.electronics.repair , in article <c2b49g$1rrl3k$1@ID-
127463.news.uni-berlin.de>, at Fri, 5 Mar 2004 17:59:40 -0600:

Also, anyone know where I could find some documentation or guides for
repairing this model? Or any safety precautions?

Probably, capacitors in the power supply are getting bad. An ESR meter will help
finding them. It would not be something that costs too much to repair, methinks.
If you want to try it by yourself, you can find lots of safety info at
www.repairfaq.org .

[]s!

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Chaos Master® - Porto Alegre, Brazil!
IRC #XLinuxNews or #POA of irc.brasnet.org , nick Wizard_of_Yendor .
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work)
CygWin, GnuWin32, and so on..

 

[wolfhedd]

ahh, is that why i keep lifting trace pads at 850 degrees? thanks for the
info... i thought maybe 700, but 550-600? ok.
wolf