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Author Topic: NC303 and DeOxit  (Read 6001 times)
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Detroit47
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« on: February 07, 2014, 03:36:16 AM »

My NC303 has a case of the cruddy band switch blues.  I have sprayed it with three different contact cleaners with only mild improvement. I am ready to get desperate I've heard a lot of talk about DeOxit. Has anybody had any experience with a 303 and this stuff? I don't want to trash the band switch through my stupidity.

John N8QPC
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Jim/WA2MER
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« Reply #1 on: February 07, 2014, 05:11:39 AM »

DeOxit is great stuff, but it won't take off stuff that needs to be rubbed off. First, use it sparingly (no need to spray the hell out of your switches, and take particular care to avoid soaking phenolic wafers that can swell and become ruined). Second, take a Q-Tip or cosmetics applicator, spray it with the contact cleaner and then gently wipe the rotating contacts.  That should do it, unless there are other problems with the switch.

BTW, my reference to a cosmetics applicator is to things that look similar to Q-Tips, but have flatter and harder ends than Q-Tips.  Q-Tips tend to snag easily and leave behind fibers on the switch contacts.

jfd
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Rob K2CU
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« Reply #2 on: February 07, 2014, 07:12:19 AM »

DeOxit works very well. Obviously be sure to turn off the radio when using it. You might also want to stuff some paper towels in and behind the area being sprayed to catch any over spray, and clean up any excess on the switch. Those cosmetic do dads work well, especially the ones with a little dense sponge molded on the end. You might also carefully examine each switch stationary contact and ensure that the fingers are closed when the moving contact is absent. Likewise, when rotating the switch, observe that each selected stationary contact is opened by the rotating contact, both top and bottom. Sometimes these things get deformed, especially by some previous well intentioned butter fingered JN.

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AB3L
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« Reply #3 on: February 07, 2014, 07:19:35 AM »

I have had the applicator D100P pen for a while. You can put the cleaner right where you need it.


http://store.caig.com/s.nl/it.A/id.1607/.f?sc=2&category=188
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Detroit47
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« Reply #4 on: February 07, 2014, 08:34:41 AM »

I'm going to go see what Radio Trash has today.
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ka4koe
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« Reply #5 on: February 07, 2014, 09:07:39 AM »

Don't buy DeOxit from Rat Shack. Its a ripoff.
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k7mdo
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« Reply #6 on: February 07, 2014, 01:47:36 PM »

Anyone reading this have any idea how (or if) one can clean more than just the contact area of the switches?

I have two dumpster retrieved Viking II's and the one that looks re-storeable has some switches on which the silver plating has turned black.  It is obviously a silver oxide but it is one there pretty good and I haven't had any luck removing it, not even mechanically with things like erasers.

The really bad looking (non-restoreable) Viking has clean switches but I simply don't want to swap the switches out just to get better looking switches.

Tom
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« Reply #7 on: February 07, 2014, 02:16:31 PM »

  It is obviously a silver oxide
Tom

Ah, that would be silver sulphide.  Silver oxide is white, very hard to form in reality.

73DG
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W1RKW
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« Reply #8 on: February 07, 2014, 02:23:55 PM »

A liquid tarnish remover will remove the heavy black tarnish but the chemical will need to be rinsed off.  One should follow up with DeOxIt Gold or Shield rather than just the cleaner (red stuff).

Applying deoxit to just the metal contacts can't be stressed enough.  Anything with HV on it and you'll have a carbon track if residue is not removed from a wafer.

Also note that deoxit comes in various formulations some of them flammable. D100 or Dn5 is non-flammable and I think the D100 is 100% cleaner with no solvent. I found out the hardway when I ran out of the older Caig formulations which were fluorocarbon based and then banned.

As far as the NC303 goes, I've had good luck cleaning with deoxit on my NC300, again applying it sparingly to the metal only.  One thing you may want to look at very closely is each wafer contact where it is riveted to see if the contact moves as the wiper moves through the contact.  I have not seen this on my NC300 but have on other BAs where the rivets loosen up slightly allowing movement. A quick dab of solder usually fixes any looseness.
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Detroit47
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« Reply #9 on: February 07, 2014, 03:15:02 PM »

I may use some tarn ex on the wafers they are pure black,and then clean them with deoxit and put their lube on as well. I can make each band respond with a little rocking of the band switch. I will look for loose rivets. I was happy to see that my signal generator would make it down to 80 kc. So I could tweak up the IF. The 2nd if is good I will check out first if and rf amp after work. I'm off to radio trash now.

John
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w3jn
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« Reply #10 on: February 07, 2014, 05:23:06 PM »

Don'T spray ANY cleaner on any switch.

With the deoxit, apply a bit to a Q-tip and use the Q-tip to apply directly to the switch wafer contacts as you rotate the switch thru its range.  This will add just a bit of abrasive and ensure you don't wreck the switch by soaking it with unneccesary chemicals.
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KA2DZT
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« Reply #11 on: February 08, 2014, 02:01:10 AM »

I clean switches all the time with WD-40 and an old toothbrush.  Works well and never had any problems.  Also 2-26 cleaner works well.  HD sells it.

Fred
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Detroit47
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« Reply #12 on: February 08, 2014, 02:37:22 PM »

I've gotten my band switch clean but I don't know if I would recommend it. I tried Deoxit and that was pretty lame stuff. I wound up using Tarn-ex with a Q tip and following it with Deoxit as a rinse. I put a squirrel cage blower on the bench to dry the mess out since i soaked it. Tarn-ex is a acid based cleaner, so I didn't want any residue. So far so good it seems all is well and the switch works like new.
 Grin John
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