The PHILCO Phorum
38 116 question - Printable Version

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38 116 question - SteveJB - 02-20-2015

I have the set playing after a recap and changed resistors as I went that I could reach.  I didn't change the .05 cap in the rear of the rf deck yet-that's next.

It plays loud and strong but the tubes were initially in so tight that I had to use a small hammer and piece of wood to tap them out of the sockets from underneath the chassis.  I cleaned the tube pins and the sockets as best I could (sprayed with tuner cleaner and lube) but they are still fairly tight and may still be corroded. 

The 6A8 Mixer tube is very touchy when I get near it or when I touch it.  The volume goes up quite a bit just hovering over it. I think the contacts are corroded in that socket as it goes from quiet to loud just by wiggling it around.

What I'd like to know is what do you guys use to clean the inside of the tube sockets?  I am going to try to get some welding tip cleaners as they might help remove any corrosion.  I'd like small wire brushes but I have never seen them that small.  Any ideas would be appreciated.

Steve

PS All voltages are a bit low but overall look good except for one tube.  The 6K7 2nd Detector should read about 40,20 and 20 volts on pins 3,4 and 5.  I only get 0v, unstable and -2.5 on pins 3,4 and 5 respectively.  I don't have a tester, is this a sign of a bad tube?  I am going to recheck the components associated with that tube this weekend. 

RE: 38 116 question - morzh - 02-20-2015

I think if you have actual corrosion the only good way to do the first cleaning is something abrasive, like a small round file, or sandpaper, or....

Then you follow with some protection, like your Deoxit etc.

RE: 38 116 question - GarySP - 02-20-2015

Hello Steve.  I've used dental proxy brushes with good results.  Kinda like mini bottle brushes made of stiff nylon bristles.  Work good with DeOxit.  You can get them at any drug store.  Take care, Gary

RE: 38 116 question - codefox1 - 02-22-2015

Pipe cleaners can be used to ream out octal sockets too. And if pins are corroded, beg a used curette from your dentist or hygienist. Will still be plenty sharp for your purposes.

And check that 6A8 (assuming it is a metal 6A8) pin 1 is solidly grounded, and if the grid cap uses shielded wire, make sure it is intact. Weak ones will play fine in some radios, will not work at all in others.

RE: 38 116 question - Eliot Ness - 02-22-2015

I found a set of brushes very similar to these from one of the tool dealers that set-up at larger car shows:

http://www.harborfreight.com/5-pc-airbrush-cleaning-brushes-68155.html


You could maybe follow up with pipe cleaners and Deoxit for the final cleaning/protection.

If the corrosion is very bad you might want to run some tightly rolled up emery paper through it first, or try these stanless/brass brushes if the small ones aren't too big:

http://www.harborfreight.com/6-piece-tube-brush-set-61923.html

RE: 38 116 question - SteveJB - 02-22-2015

(02-22-2015, 12:24 PM)Eliot Ness Wrote:  I found a set of brushes very similar to these from one of the tool dealers that set-up at larger car shows:

http://www.harborfreight.com/5-pc-airbrush-cleaning-brushes-68155.html


You could maybe follow up with pipe cleaners and Deoxit for the final cleaning/protection.

If the corrosion is very bad you might want to run some tightly rolled up emery paper through it first, or try these stanless/brass brushes if the small ones aren't too big:

http://www.harborfreight.com/6-piece-tube-brush-set-61923.html
Thanks, I was going to head over there this week and look for the metal brushes. Good to see they have them.  I'll also look at that 6A8 more closely.