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 Post subject: New resistor in old grid leak housing
PostPosted: Mar Sat 03, 2018 4:14 am 
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Joined: Sep Mon 18, 2017 2:23 am
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Location: Plymouth, MI
I have a Philmore grid leak that's gone bad and I was wondering how you get the ends off without destroying the grid leak all together. I have one radio that someone else did this procedure on and they did a great job. What do you use to re-seal the ends? Super glue? It probably would work. Any tips from some of you who have done it would be appreciated.

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Dan

I know just enough to be dangerous.....
(Member - Michigan Antique Radio Club)


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 Post subject: Re: New resistor in old grid leak housing
PostPosted: Mar Sat 03, 2018 6:23 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 12573
Location: S. Dartmouth MA 02748-1225 USA
I have a few times...

I used a Weller soldering gun and wedged the brass end of the leak in between either the tip or the heavy extension from the body of the gun. The tip remains in place connected. Trigger the gun and current will flow, mostly through the brass end of the leak. It will expand in short order, loosening it from the glass. It was probably held on with sodium silicate.

I use two pairs of common pliers that I had put heat shrink over the ends so the pliers now have a soft jaws. With those pliers, one of which I pluck the cold end of the leak from the gun and the other grasping the hot end, twist off the hot end. Note there will be solder so it may splash. Letting the glass and the decal cool, repeat on the other end...

Sometimes the glass tube will crack and spoil. If the label could be scanned, possibly a facsimile could be made.

FWIR a 1/4 or 1/10 watt resistor will fit within the glass tube...

The brass ends will have to be re-heated to move the balance of the solder. Using the pliers with soft jaws so not to scratch up the nickeled brass. A scraper made from a small old triangle file is used to remove the last of the solder so the cap will fit on the end of the glass tube. The wire for the resistor is measured and a drill, a little larger that the lead of the resistor is passed through the center of the end of both caps. The resistor can be painted or not to hide the color bands.

Do a dry assembly of all the parts to estimate where the resistor should be soldered to be in the center of the glass tube and then solder one end. Assemble completely and solder the other. It should hold together on its own. However, a tiny drop of liquid super glue should make the package complete.

The same can be done to A-K grid leaks... however, the brass ends will have to be drilled for a larger, standard borosilicate glass tube, it is a common size. Then follow the same procedure to assemble.

As you know A-K used a different configuration of grid leak and clip holder.

Oh, if you have a resistance soldering station it would do the same work as the Weller gun.

Darn, I wish I could have brought home the American Beauty resistance soldering station I had at work. Very pricey unit. My replacement could not even figure out how to use it. Much of the resistance work had gone away by the time I left... Cats meow to solder wire into large Amphenol connectors. Never melt the insulation

GL

Chas


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PostPosted: Mar Sat 03, 2018 4:17 pm 
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 Post subject: Re: New resistor in old grid leak housing
PostPosted: Mar Tue 06, 2018 2:28 am 
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Joined: Sep Mon 18, 2017 2:23 am
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Location: Plymouth, MI
I finally got around to restoring my Philmore grid leak. I used a soldering iron to heat the brass ends and melt whatever the adhesive was that was holding the ends on (packing peanuts on a pair of needled nose pliers gave me a good grip without damaging anything). After removing the insides of the grid leak, I cut the leads on a 3.9m ohm resistor, put the resistor in the glass tube and bent the leads around the glass. This saved drilling the tiny holes and soldering. I reinstalled the brass end caps with gorilla glue and got a good snug fit over the resistor leads. Then I tested it.

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Dan

I know just enough to be dangerous.....
(Member - Michigan Antique Radio Club)


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 Post subject: Re: New resistor in old grid leak housing
PostPosted: Mar Tue 06, 2018 4:24 am 
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Joined: Jan Thu 01, 1970 1:00 am
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Location: S. Dartmouth MA 02748-1225 USA
WOW :shock:

First class Dan!

Looks great, I like the padding on the pliers too!

I'm surprised you had such a loose fit on the brass ends that the leak could be assembled without drilling.

Hey, what ever works!

Chas


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 Post subject: Re: New resistor in old grid leak housing
PostPosted: Mar Tue 06, 2018 2:59 pm 
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Joined: Sep Mon 18, 2017 2:23 am
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Location: Plymouth, MI
Thanks Chas!

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Dan

I know just enough to be dangerous.....
(Member - Michigan Antique Radio Club)


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