[AMPS] Blue Flashes from SB-200

[Vic Rosenthal]

Dean Wood wrote:
> 
> Whenever I key the SB-200 with my transceiver, I see
> varying degrees of blue flashes on both 572B tubes.
> At very low drive levels (10W), I see a blue tint on two
> sides of both tubes.  At high drive levels, blue flashes
> actually jump through the top of the SB-200 chassis,
> providing for quite a light show.

Blue glow from the glass of the tube envelope is harmless; it's caused by
electron bombardment.  If it appears that the area inside the plate is glowing
it may be a sign of gas in the tubes, in which case you will probably need to
replace them.  Are you getting normal output, plate/grid currents, etc.?

73,
Vic, K2VCO
Fresno CA

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