Hi Jim,
Be sure that the ceramic is clean on the tubes. Even oily fingers can cause
some leakage at high voltages.
Also be sure to connect unused elements together when testing.
When checking plate to grid, tie the cathode and filament to the grid.
When checking grid to cathode tie the filament to the cathode and plate to
the grid. Never leave any elements floating during hi-pot testing.
73
Gary K4FMX
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com]
> On Behalf Of Jim Barber
> Sent: Wednesday, April 04, 2012 9:32 PM
> To: Amps@contesting.com
> Subject: [Amps] YC156 BVT measurements
>
> I just picked up a "virtually new" YC156 - with 12 minutes runtime. I
> decided to test it on the BVT against a used/good MRI pull I have the
> shelf. Since the BVT is new to me I found some interesting things and
> thought I'd post for comment:
>
> LEAKAGE
> Anode-Grid NEW USED
> -------------------------------------------
> 5000 - -
> 5500 - 5uA
> 9000 - NOT TESTED
>
> Cathode-Grid NEW USED
> -------------------------------------------
> 600V 5uA 5uA
>
> So... Since I'm new at interpreting these results, here they are for
> comment. Do you agree?
>
> (1) I need to getter the used tube before putting it into service
>
> (2) Cathode-grid isolation is surprisingly low on these tubes, but since
> both new and used tubes tested identically across those elements I'm
> going to assume this is normal. I have a third tube that I can pull out
> of storage and test to increase the sample size, but I want to collect
> any comments first.
>
> Thanks,
> Jim N7CXI
>
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