>
> I have fixed that by discharging about a 1000 ufd cap charged
>to about 15-20 volts between the filament/grid. No promises!
>
The hat trick is to fix it so that the tube does not short when at normal
operating temp. To do this, you need a tube that exhibits a cold g/f
withstanding potential of 6 to 9 kV. To straighten bent filament
helices, we apply 10g for 20 - 40 seconds with a fil potential of c.
5.6v.
cheers, Mark WB8JKR
>
>
>On Fri, 31 Dec 1999 10:57:02 -0800 nospam4me@juno.com writes:
>>
>>I've got the source of much trouble here in my hand... a 3-500z with a
>>cathode to grid short. Anyone care to suggest a method to possibly
>>open the short. I won't trust the tube in an amplifier again, except
>>maybe a
>>construction place holder.
>>
>>skipp
- Rich..., 805.386.3734, www.vcnet.com/measures.
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