[Johnson] FW: Pacemaker

[Langston, Mike]

I have started the alignment sequence in the manual. VFO alignment
(tracking) proceeded with no problems. Next section is xtal osc. Time
out while I built an RF probe. Turned the rig on it's side and turned it
on to let it warm up (standby position). 3-5 minutes later a slight
buzzing sound and the 5A fuse let go (one in the xfrmr primary - got rid
of the fused plug). Replaced with 5A slo-blo and watched closely this
time when I turned it on. Same time delay and started hearing the buzz.
The 6146 final looked like it was on fire inside with a pulse that
matched the buzz frequency. Turned it off.

 

Tested the 6146. Filament lights but reading is 2000 on my Stark 999.
Minimum good reading is advertised as 4100. A new 6146B tests 4500-6000
(I've got a bunch of them). This same tube tested good when I first
checked it.

 

Could having the rig on its side have caused something to sag and short
inside the tube? I've had finals self-oscillate before (HT-44) but there
was no associated light show. I don't really want to ruin a 6146B just
to satisfy myself that there was nothing wrong with the original tube. 

 

Any ideas?

 

Thanks in advance.

Mike KL7CD

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