[Amps] grid fuses

[Will Matney]

Peter,

Would you send back a gassy, or even slightly gassy 3-500Z to the manufacturer to have it gettered or a new vacuum pulled on it? I'm still sticking with what we first started with here, that tube none others. Large transmitting tubes can be cured if sent back as they cost enough to justify it. Actually Tom makes a good point about them. The main thing in question is, do you believe an arc can happen in the correct vacuum for that particular? To me, a tube shouldn't break down and arc at its recommended anode voltage, or it's maximum anode voltage. To my opinion, even though the tubes came out of a box, they could have been sitting on the shelf of the seller, or the manufacturer for a good while long enough to loose a little vacuum. One would never know unless they looked at a date code, etc. Still at that, they shouldn't arc in service.

Best,

Will

*********** REPLY SEPARATOR  ***********

On 7/22/06 at 3:22 AM Peter Voelpel wrote:

>Not really,
>
>its quit common that tubes like YL1050, TH347 etc. which are very high gain
>metal ceramic tetrodes for linear mode of small tv-transmitters and linear
>service arc internally from time to time.
>It does not matter whether they are new out of the box or being in service
>for a long time. 
>Those tubes are extremely expensive and nobody throws them away.
>Everybody uses the circuitry in the power supplies which the manufactory
>suggests and never a grid fuse or grid resistor but direct ground
>connection.
>The YL1056 in my 2m amp is running now perfectly for almost 20 years with
>regular arcs even in standby, it does not matter at all, the P/S quickly
>resets and during a contest I do not loose any qso by that.
>
>73
>Peter 
>
>
>-----Original Message-----
>From: amps-bounces at contesting.com [mailto:amps-bounces at contesting.com] On
>Behalf Of Will Matney
>
>If a tube arcs internally, it's gassy as an arc can't form in a vacuum. It
>needs to be replaced no matter what
>
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