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

[BOYDSIRBOYD at aol.com]

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.
 
that's the last problem I have with it now.
 
here's how it died Thursday evening,,,  the power dropped like it was  
suppose to in the evening, but then a hissing cracking noise was coming out of  the 
transmitter (as I was told). the owner turned the plate voltage off,  then 
turned it back on with the same result.  he called me and I went in to  find the 
suppressor grid cap (C 51) had blown open because when I  fired up the plate 
voltage that's where the arcing was.
well I got a replacement the next day, just to make sure I changed  the pa 
tube (in case in was shorted and caused the original  problem). well the high 
voltage came up and it started arcing  from the output of the pa tube to the 
neutralization plate just behind  it. also found the long circuit board behind 
the meter panel and the control  panel had burned. that killed any 3 phase meter 
reading, but it would work with  all the rest.
I also replaced it and all meters work fine.
 
and that's where I am now.
 
BURT in Columbia sc  told me about the continental fm rigs doing the  same 
thing because of the plate transformer internally shorting, I needed to  isolate 
the transformer from the rest of the transmitter. I tried that with a  board 
between the transformer and the bottom plate of the transmitter. no  luck,,  
same arcing..
 
now meter information,,, as soon as I hit low power button the high voltage  
meter pegs ( max on meter is 15kw volts), the transmitter should go no higher  
than 14kw volts.  the plate voltage starts to come up but arcing occurs  
before the meter reaches it's place on the scale,  the plate current  comes up and 
arcing occurs when as the meter reaches it's point.
I feel the plate transformer has a short causing the extreme arcing on the  
pa tube...
 
ok all engineers what are your thoughts??
 
bill   wdab  wasc  wcsz  wtoy  wabv 
 
P. S. and PAUL WALKER, no comment from the peanut  gallery.



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