[BC] CONTINENTAL 315R-1 5KW AM TROUBLE

[Alan Alsobrook]

Ok, I'm assuming that the arc is a fuzzy one rather than a BANG!.. This 
of course indicates that the arc is RF, not DC. Most likely this is a 
case of one problem causing many more (as arc's like to do).

This may seem like left field, but it's really not, first check the load 
and the output network of the transmitter, making sure the load is 
correct and the output network is all good. RF arcs from the plate area 
of the tube generally indicate an open or very highly reactive RF path 
to the output. Also check the phoenelic of the vac cap, it likes to 
carbon track internally.

I doubt it's low drive since you would have diminished rf output. Of 
course you need to do standard troubleshooting to verify your HV 
metering circuits and verify weather or not you are really seeing a true 
HV overshoot like your meters are indicating. Typically if that's a true 
indication it's followed quickly by DC arcs and breakers tripping.

PS I'm tossing this over to tech assist as well so it will have a better 
SN ratio..

BOYDSIRBOYD at aol.com wrote:
> to the brain trust,
>  
> I have for the last 3 days racked my head literally on this  transmitter (and 
> boy does that hurt).  the trouble I have is that the  high voltage on the pa 
> tube wants to arc (and a good size one too) to the  neutralization plate (C 
> 46). I have went through every power supply's in this  thing. the switch mod 
> bias +125 V / -125 V supply, the 28 V supply( I did find R  9 and R 6 both bad) 
> and the logic power supply.

-- 
Alan Alsobrook CSRE AMD CBNT
St. Augustine Fl. 32086 904-829-8885
aalso at Bellsouth.net