Amps
[Top] [All Lists]

Re: [Amps] 3-500Z pin becomes unsoldered

To: amps@contesting.com
Subject: Re: [Amps] 3-500Z pin becomes unsoldered
From: Pete Smith N4ZR <n4zr@contesting.com>
Date: Mon, 19 May 2014 05:25:55 -0400
List-post: <amps@contesting.com">mailto:amps@contesting.com>
For whatever it is worth, I had this problem frequently in contest service, even with the higher-capacity Harbach fan. Finally, I swapped the filament springs for two from the grid, polished the tube pins and the insides of the contacts, and have had no problems thereafter. I could have done these things one at a time, but who believes in the scientific method anyway?

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 5/14/2014 9:55 AM, Carl wrote:
That Johnson 122-275 ceramic socket goes back to the 50's when just about everything used expensive Eimac forced air flow cooling and the cast aluminum sockets with chimneys cost more than the tubes. Johnson received an OK from Eimac for horizontal cooling in their 4-250A/4-400A transmitters and amps and other companies followed suit.

The SB-220 cooling is well thought out and sufficient as designed. The problem is builders and other owners who cannot read the manual and dont place the fan blade at the proper point on the shaft and/or leave off that small aluminum air deflector on top of the perforated cover. Failure to clean the blades and lubricate the motor just adds another level of problems.

The socket uses a rivet to assemble the pin and when the tube pin overheats that compression bond is weakened. A cure is to gently compress the pin to original spacing and then use a D-550 or similar gun and a bit of diluted hydrocholric acid, also sold as plumbers soldering fluid, and flow some silver bearing solder to bond it all together. Use a toothbrush and the acid to remove the heat bluing. Flush out the acid residue with a water and baking soda mix in a spray bottle.

Others may be more comfortable replacing the socket (-;

I dont like the Chinese sockets as it is easy to rupture the tube seal especially with the older all glass base without the brown compression ring. Ive heard a few stories of that happening with both versions.

In the hundreds of 3-400/500 amps Ive worked on only a very small number required replacing the socket which were broken by a users brute force attempt to restore tension.

Carl
KM1H




----- Original Message ----- From: "Alf Pousar" <alf.pousar@surffi.net>
To: <Amps@contesting.com>
Sent: Wednesday, May 14, 2014 4:15 AM
Subject: [Amps] 3-500Z pin becomes unsoldered


If your solder lugs are dripping the solder due to heath, clean the lug using a good desolder wick and wrap the wire around and trough the lug. Then take some small wrapp wire and wrapp around the lug.
Then... solder with high temp ten/silver solder and the problem is gone.

Alf  OH2QM
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps


_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps


_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps

<Prev in Thread] Current Thread [Next in Thread>