Rescued 2001 RCA 36" F36669 with rainbow
 

Turns on and runs fine but I noticed discoloration at top right and bottom left of screen. Changes when I move it around the room. In another location, it was bottom right and bottom left. Any ideas?

It needs the CRT Degaussed.

It's supposed to do it automatically every time it's turned on cold, but their could be something wrong with the Degauss circuit, or the tube could be magnetized to an extent that the internal degauss coil can't fix it, if that's the case you will need to use an external degaussing coil like this one:

http://www.ebay.com/itm/GSG-Televisi...item5b0ff860df

Another possibility is the Shadow Mask inside the CRT is damaged, this can happen if the set was dropped or knocked over at some point, there's no fix for that except a new tube.

Degauss thermistors fell apart left & right on these.
IIRC its near where the AC cord comes in. Dime sized
& has leads soldered to it. You can usually resolder the leads.
Also IIRC these had orientation switches on the back marked
E-W etc. Dont remember how to set them though:scratch2:

BTW whats the chassis number CTC###

73 Zeno:smoke:

ctc203c. It moves around the screen when moved as gravity affects it.

http://www.videokarma.org/attachment...1&d=1428772475

Thought it was the older chassis. IIRC the 203 was the
last real RCA chassis. Look near where the DGS coil plugs
in for the thermistor.

73 Zeno:smoke:

The Earth's magnetic field could do that. Tap not real hard on the cabinet, and see if the false colors flap "in the breeze".

Do you hear a short buzz when you turn the set on when it's cold (ie, not been running for several hours). If not, the thermistor probably broke, and the set isn't doing a degauss upon power up.

Exactly! :yes:

While you are in the TV, check the solder on the Pincushion board - that was the number one gripe we had with the '203 - bad solder joints causing all sorts of problems. IIRC, it's on the right side of the chassis when looking at the back of the set.

Cheers,

And above ALL...the connections on the horizontal driver transformer path too !!

I would definitely try and degauss that tube. Those RCA tubes of that era are VERY reliable. a 207768 RCA part will replace the thermistor

I will open this up in the next couple of days and post what I find.:thmbsp:

Labeled C14207 on the board? near the ac line at back right corner. Don't see any loose connections or welds. I don't hear any sound that you normally get when first turned on. Just the first relay click and then the second. Otherwise very quiet.

Should be marked with an R number not C.
Not sure on the CTC203 but earlier chassis turned on/off
by turning on the hoz osc. The relay is for degauss & will
click twice. The relay contacts, thermistor & degauss coil
are all in series.

73 Zeno:smoke:

Been awhile since I saw a manual....but pertty sure you are right. Think the 203. ALSO has a constant running SMPS_-and it just switches the horiz on and off too, maybe along with a couple of lower lines. . In standby--it goes up some above the run level.....but more than full B+ is there on the H-out in standby. Relay only for degauss. If you are not hearing a pretty loud hum, for a second at turn on...the degauss ckt it NOT working. Coil might even be UNPLUGGED from board, near thermistor.

coil is plugged in. unplugged and plugged back in. No hum at all. just the two clicks. I did notice after having the back off and after cleaning that the colors are even worse now when turned on. Will get a pic of how it is now. Should I change out the thermistor? Its blue and located at the back edge near the power cord.

Can you get a hand degaussing coil....and go over the tube? If it is ok....you should be able to clear the problem up. just make SURE....it is at least 4 foot away from the set---when you plug in coil.. and then before you unplug the coil.

it MAY be so heavily magnetized.....that it takes some passes of the coil, over the front of the set and even behind it. just keep it AWAY from the neck of the tube.

I don't have one but I could probably order one on ebay. What should one cost?
http://i800.photobucket.com/albums/y...pslaok9zgj.jpg

http://i800.photobucket.com/albums/y...psqjvcr0ku.jpg

A soldering GUN may also work as a degaussing coil in a pinch.

+1 - I used to degauss computer monitors aboard ship with a Weller 8200 Soldering gun. For the 19" Zenith we had in the office, we had to use a degaussing coil. You can make your own - 22 gauge wire, 34 turns in a 12-13" diameter coil. I put a momentary rocker switch in mine - others use a plain rocker switch. Wrap the whole thing up in electrical tape, wire the switch in series with the coil, adding a 8' power cord. We extended our cord - sometimes when using in a customer's home, the nearest outlet was 1-2 feet beyond the cord length.

Where to get the wire? Junked BPC sets. Look for copper wire - aluminum wire heats up, and you don't want hot wire in your hands. If the connections to the coil are soldered, it's copper - for aluminum, they used crimps.


Cheers,

About $45.83 http://www.ebay.com/itm/COLOR-TELEVI...item5b0f3c0474

Some of them are cheaper but then the shipping is higher, probably not worth the cost for a one time use on a set that may have more serious problems.

If you have a Weller Soldering Gun I would try using it as a degausser first.

And to think, I just scrapped several from junk sets I scrapped out. I have a switch somewhere as well but not sure what type. Only iron I have right now is a $7 cheapo from Wal-Mart. need to upgrade on that soon. I wonder how many sets I'd have to tear down in order to have enough wire.:scratch2:

A big screen set's degauss coil should if looped down to ~14" should last a minute or two at line voltage before getting hotter than you want to handle.

If you take that and watch the temp it should work.

If you make your own coil you MUST put a
spring loaded switch on it. Once the boss degaussed a
set & just put the coil down. He ran an errand & when
he got back the place was full of smoke & the coil melted into the
set he put it on.
Dont get me wrong I am not a paranoid safety nut. In fact I
am always ripping off safety tags & those damn furniture
tags !!!

73 Zeno:smoke:

I dont think its blue. That is probably a MOV metal oxide varistor.
Its purpose in life is to short out & blow the fuse with a large
surge.
Most thermistors are silverish-grey, dime sized & have the
leads solder on the sides.

73 Zeno:smoke:

And you said it begins with an "R". I'll check it again.

Looks like RT14201. There's a rectangular print on the board with two wires coming up and hooking over toward each other at the top. Moved the tv into the other room and now most of the correct color is back. rainbow is at the bottom now, lol

So this is all I need.

http://www.videokarma.org/attachment...1&d=1429205466

You need to be sure that it's the right kind of thermistor. Some drop resistance when they get hot (used in PC power supplies), not what you want here. You want a thermistor that increases resistance when it gets hot. Any BPC set will have one (often enclosed in a plastic squarish box), and you could use its degauss coil as well.

The thermistor pictured above is 100% Right, per RCA.

i'll have to order one in a couple weeks. Looks like around $11.

What is your location? I may have one or two, used but good. CTC18X-CTC201 (and possibly the ATC101/M134 chassis) all used the same part number thermistor per RCA. If you are in the US, PM me your address and I'll get one to you. I junked a curb-crawl RCA CTC203 in 2010, and another RCA not-sure-of-chassis in 2012.

Of note - most BPC sets of late (as WA2ISE correctly pointed out), use a PTC thermistor, usually 15-25 ohms. I had a stock of RCA 141239 thermistors I used or gave away, and they replaced about 90% of the 2 legged kind in 32" and smaller sets.

I scavenged the 3 legged TDK/Kamko thermistors from anything I junked, so I had plenty of both kinds at one time. I may still have one or two, but just about any 2-legged thermistor from a BPC set will replace any other. For a 36" set such as this RCA, the inductance/resistance of the coil places a bigger load on the thermistor, so you'll want to have the original type if possible for longer thermistor life.

Old sets using the thermistor/varistor combination used an NTC thermistor, and most are replaceable with a Workman FR191, FR291, or FRTV kit. Oneida, Ambassador, and GC Walsco had similar thermistors with similar part numbers (GB191, GBTV, etc.), typically 100 - 150 ohms cold.

Just please - don't go buying a 25 dollar thermistor on eBay - what a ripoff. My CTC16 has a new Workman I got off of eBay for 2.99, plus 4 bucks shipping. ......and then I found my stash of thermistors. :grumpy:


Cheers,

PM sent.

pm me your address i will send you one no charge.

PM sent.

Success! Installed new thermistor and working great. Thanks rcaman!:thmbsp:

http://i800.photobucket.com/albums/y...psuil6id3k.jpg

http://i800.photobucket.com/albums/y...pstgtgzyxt.jpg

I have ALWAYS wondered if Rusty would been allowed to keep those cars--since he was UNDER AGE_-when he bet on them.

BEAUTIFUL pix BTW..SO glad it is good now !!

those sets always had a nice picture.this one looks great.

LOL, Thanks. Im a big fan of any movie with the Griswolds. I imagine if they found out, he'd have lost them. Papageorgio, lmao.