Salvaged degaussing coil? - Videokarma.org TV - Video

Phil Nelson · #1 10-15-2006, 04:16 PM

OK, I understand that my newly acquired CTC-11 (my first color set!) will need degaussing.

A few weeks ago, I salvaged various bits from a broken 1980s Sears color set that my wife had bought for $2 at a garage sale. Among those things was what looks like an automatic degaussing coil (2nd photo, where my son is holding the salvaged coil in front of my CTC-11).

I have a book that explains how, with a portable degausser, you would turn it on holding it next to the CRT, slowly move it away after a few seconds, then turn it perpendicular to the CRT before turning it off.

The coil measures around 4 ohms resistance.

Question: Can I just wire on an AC cord and stick it into my variac? And if so, what would be a reasonable voltage to use?

The book explains the theory of how some automatic degaussers work, but gives no clue to actual working voltages, values of thermistors & varistors, etc.

Phil "new to color" Nelson

captainmoody · #2 10-15-2006, 05:23 PM

Hi Phil,
Go with a regular degauss coil like the shops (used to) use. That one will melt down if you give it power longer that a few seconds. It is intended to be used with a thermistor.

Chad Hauris · #3 10-15-2006, 06:50 PM

You probably could safely put the coil in series with a 100 watt lightbulb...I am not sure if the effect would be strong enough but it shouldn't overheat it that way.

blue_lateral · #4 10-15-2006, 06:51 PM

They come across Ebay all the time. Meissner made one, as did a lot of other companies. Go for the big round one, rather than the little oval kind.

Mine is custom made by a friend who was working in a motor rewind shop at the time (a long time ago).

The one referenced in this thread http://audiokarma.org/forums/showthread.php?t=85071
looks just like the old ones (pretty much) , but for 50 bucks... I'll bet you can do a lot better on Ebay.

John

reeferman · #5 10-15-2006, 08:59 PM

I have used a Weller 140 watt soldering gun for 40 yrs with excellent results. Hold the gun on the face of the CRT (in the center). Turn the gun on and start making an outward circular motion while moving the gun away from the screen (experiment, won't hurt anything, especially thr gun). Get a few feet or more from the screen and turn the gun off. The less wattage the gun, the longer the "hang time" in front of the screen. Piece of cake.

I think I still have a rinky-dink one I bought in the '60s, measures I guess 8" or so. If I find it, it's yours for the freight, but the 140 watt Weller works better.

RetroHacker · #6 10-16-2006, 05:36 AM

You can use the degauss coil from a junk TV and wire an AC cord on - but like previously mentioned it'll melt and heat up real quick. What you need to do is get two or three junk degauss coils, and coil them up together so they're about six or seven inches in diameter, and wire them in series. And look for bigger sets to salvage - like 27 inchers, they'll have larger coils. Wire the coils in series and put a momentary push buton in there (one that's rated for 120v and lots of current), and wrap the whole mess in tape.

-Ian

bgadow · #7 10-16-2006, 01:10 PM

I have had good results with soldering guns, better results with a bulk tape eraser I found in a junk pile, best results with the real thing. Several old TV repairmen gave me their old ones-maybe you could ask around. But all of the above will work fine. I tried a salvaged coil from a later model set and the thing started smoking before I could even unplug it.

Tony V · #8 10-16-2006, 01:23 PM

I picked up a NOS one on ebay awhile back for $15 postage included so their still available.
-Tony

blue_lateral · #9 10-16-2006, 02:26 PM

This looks like the real thing

http://cgi.ebay.com/Degausser-Degaus...QQcmdZViewItem

John

Geoff Bourquin · #10 10-16-2006, 08:49 PM

I saw a coil new-in-box at Frys in Seattle area a couple days ago for $39.95.
I have 2 coils. One factory-built for servicers from about 1960. The other is the internal coil from a tube-type TV. I doubled it up, added a cord and switch, and taped it real good. I've been using it for 25 years. It'll degauss your TV from across the street! Oh, and it does get very warm. I avoid powering it up for more that 30 seconds, and after a minute it's uncomfortable to hold. I can't use it in an explosive atmosphere, as the spark in the switch when I disconnect that much inductance really lights things up.

Phil Nelson · #11 10-17-2006, 02:40 PM

Thanks for the advice. I have a couple of big old soldering guns, so maybe I'll try that trick first -- after I do all the other restoration work!

Phil

Whirled One · #12 10-20-2006, 08:31 PM

By the way, another source for new service-style degaussing coils is MCM (www.mcminone.com). Product # 72-790 is the nice big round style, and it's $32.95; they also have the smaller (and wimpier) plastic-covered ones for $20.95. Note that these appear to go on sale quite often, however (you can check their active sale flyers online), so you may want to wait a bit.

[Note: I've never tried either of MCM's deguassing coils, so I can't really vouch for them aside from the product descriptions in their catalogs/web site. I've had pretty good luck dealing with MCM in general though.]