>
>my amp supply lk-500 zb did a funny thing a while back when I powered it up
>after a long time in the closet and a cross country move. so far I have
>found a blown 1 ohm, 5 watt wire wound resistor. it was in two pieces so
>there is little debate on whether or not it blew...
>
// Where was it in the circuit?
>one area that was suggested as a potential problem was an internal short in
>one or both tubes.
>
// If you can see the anoode cooler touching the grid, you have an
internal short.
>I pulled them and did a vom check for short vs open across all pin
>combinations. both tubes are eimac 3-500z
>
>if one looks at the bottom of the tube with the plate away, there are 5
>pins. one is by itself
// This is pin 3. Count clockwise. Pins 2, 3, 4 are grid. Pins 1 and
5 are filament.
> and the other 4 make up the rest of the array. ... ...
>I would guess that the 3 pin set are connections to the grid and the 2 pin
>set is the filament.
>
>so from a low voltage standpoint, it does not look like there is a short
>between either the filament or the grid and the plate nor between the grid
>and the plate nor between the filament and the grid. maybe at 3000 vdc,
>things change...
>
>comments?
>
// If the anode cooler is not touching the grid, I would suspect a
parasite.
>jim
>N1NK
>x AB6R
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
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>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734, AG6K, www.vcnet.com/measures.
end
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