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Hello all, I have been playing around trying to get my old sb220 working. Just a run down of what’s done inside the box. First off I have 2 mismatched tubes one old eimac and one newer graphite style. Could this be my issue right off the bat? I put in the nomadradio bias board. And it appears someone before me did the “self bias mod” on the relay. Not sure if that conflicts with the nomadradio board. I have 3.4kv plate voltage, under driver I’m pulling both plate and ride current. Driving with 40w rms 80w peak AM. When I key the amp I see no difference in power on the meter. Iv checked the band switch and relay. Any ideas on where to look next are appreciated.

[QUOTE="JimboSlice, post: 854759, member: 66356"] Hello all, I have been playing around trying to get my old sb220 working. Just a run down of what’s done inside the box. First off I have 2 mismatched tubes one old eimac and one newer graphite style. Could this be my issue right off the bat? I put in the nomadradio bias board. And it appears someone before me did the “self bias mod” on the relay. Not sure if that conflicts with the nomadradio board. I have 3.4kv plate voltage, under driver I’m pulling both plate and ride current. Driving with 40w rms 80w peak AM. When I key the amp I see no difference in power on the meter. Iv checked the band switch and relay. Any ideas on where to look next are appreciated. [/QUOTE]

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