[Amps] SB221: Can you saftely mix and run an Eimac 3-500Z with and RF Par...

[rlm]

On Apr 4, 2004, at 7:32 AM, Gudguyham at aol.com wrote:

> In a message dated 4/4/04 10:19:29 AM Eastern Daylight Time,=20
> jaking at es.co.nz
> writes:
>
>
>> How much can you safely miss match tubes? Does this extend so far
>> that one could run an different brand tube, Ie an RF parts 3-500ZG-RF=20=

>> or a
>> Taylor 3-500ZG with and Eimac 3-500Z?
>>
>>
>
> Hello Jeff, have a look at the tube, I will bet that the pin came=20
> unsoldered
> from heat and sparking occurred in between the tube pin and the outer=20=

> pin.
> The sparking causes an insulation type deposit between the inner pin=20=

> of the tube
> and the outer pin.  If you can generate enough heat to remove the=20
> outer pin,
> clean it up and the outer pin and re-silver solder the pin back on,=20
> the tube
> may still be good.

=F0  However, the old solder is Pb-Sn (lead-tin), which should not be=20
mixed with silver solder, so first remove the old solder with=20
solder-wick before flowing in silver solder.  Also, in this application=20=

use rosin-flux, and not HCl-based  acid-flux,

> Take an ohmmeter on lowest scale and measure the filament
> resistance using the tips of the probe underneath the isolated base of=20=

> the tube
> where the pin emerges from the glass.  Read the resistance of the=20
> filament,
> it should be about .6 ohms.  If it is, then measure the resistance=20
> using the
> pin.  If it is higher, that proves the connection of the tube pin to=20=

> the outer
> pin is bad.  You may be able to save the tube if you can resolder the
> connection after you clean up the sparking deposits.  Good Luck and=20
> let us know.  As
> far as the mixing of tubes, Perhaps the 2 mismatched will work OK,=20
> maybe it
> won't.  Try it out and see what happens. That is the only real test. =20=

> I do not see
> any problems with testing them, the only thing that can happen is that=20=

> less
> than optimum performance will be realized.  You may be surprised that=20=

> it will
> work just fine!  73 Louie
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>
Rich Measures, AG6K, 805.386.3734.  www.somis.org/