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 Stromberg Carlson Model 4a17
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 Return to top of page · Post #: 1 · Written at 9:24:21 AM on 19 September 2023.
Bowler's Gravatar
 Location: Bongaree, QLD
 Member since 26 October 2018
 Member #: 2308
 Postcount: 81

Hi All, what is the best way of repairing an EBF35 VALVE. I have tried tying wire around the base without success. However the valve works well when wrapped in aluminium foil. bowler


 
 Return to top of page · Post #: 2 · Written at 6:35:10 PM on 19 September 2023.
Redxm's avatar
 Location: Tamworth, NSW
 Member since 6 April 2012
 Member #: 1126
 Postcount: 466

Electrolube silver conductive paint

Ebay is one source, WES is another


 
 Return to top of page · Post #: 3 · Written at 9:56:28 PM on 19 September 2023.
DangerousDave's Gravatar
 Location: Toongabbie, VIC
 Member since 1 September 2020
 Member #: 2438
 Postcount: 131

I’ve had success with exposing the existing copper wire band around the base and repainting the glass with a carbon lacquer mixture. I then usually overcoat it with the gold or red paint as per original. Ground up carbon mixed in quick dry lacquer works well.


 
 Return to top of page · Post #: 4 · Written at 10:01:25 PM on 19 September 2023.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5303

I have had an article on that published in "Radio Waves" and with permission in Canada.

Two things happen with metallisation on Philips tubes: One it comes off and two; separation from the earthing pin, due to people dragging instead of prising the tube out by the envelope, breaking the bond.

I used conductive glue on a frame. You need to re-establish contact with pin 1 from the outside. Tube here is still in service. The article should still be buried on one of the Terabyte BU portable drives.

I will send Brad a photo of it; its a Pentagrid ECH35. Pin 1 metallisation. Glue probably Jaycar SKU: 127257. It needs coating.

Marc

ECH35 Radio Valve


 
 Return to top of page · Post #: 5 · Written at 7:32:48 PM on 20 September 2023.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2039

The "correct" way would be of course to spray new metallised red paint on the valve including the tie wire that sits at the top of the socket. This wire internally goes to pin1. After it dries you could stencil the valve number on.

However because I am lazy I just firstly wrap aluminium foil around the glass then hold it in place with tape. Then I wrap several turns of bare wire around the foil and tape this down too. The end of the wire is run to pin1 and soldered on. This works fine. I'll also add a small sticker to the valve with the type number written on it. Looks ugly, but it works well.


 
 Return to top of page · Post #: 6 · Written at 7:46:36 PM on 20 September 2023.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7342

Photo uploaded to Post 4.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 7 · Written at 8:52:42 PM on 20 September 2023.
DangerousDave's Gravatar
 Location: Toongabbie, VIC
 Member since 1 September 2020
 Member #: 2438
 Postcount: 131

By overcoating the conductive layer with red paint has the same effect and the result is quite nice. I do most of these types valves that I come across in repairs now. The gold finish is little harder to replicate faithfully.

Radio Valve
Radio Valve


 
 Return to top of page · Post #: 8 · Written at 10:13:12 PM on 20 September 2023.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 5303

With this one I was lucky, the wire wrap was still tied to pin1. So I placed a collar at the top & secured the spiralled silver wire, all the way down with Araldite (dobs).

Bottom end was soldered to the wire wrap. Only then was the glue applied to the cleaned glass, let set, then coated.

Naturally the tube, albeit experimental at the time, was tested and was good. One does not waste material on a dud.


 
 Return to top of page · Post #: 9 · Written at 9:49:23 AM on 23 September 2023.
Brad's avatar
 Administrator
 Location: Naremburn, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 7342

Photos uploaded to Post 7.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 10 · Written at 9:20:52 PM on 23 September 2023.
Robbbert's avatar
 Location: Hill Top, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 2039

That looks really nice.


 
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