[ARC5] Tip: Before You Power Your BC-230 Transmitter...

[David Stinson]

While attempting to get a crystal-controlled TX coil set 
to function on 3885 KC, I just got a nasty surprise.
The BC-230 transmitter (SCR-183) uses a coil 
and variable cap in series for neutralization.  
See:
http://home.netcom.com/~arc5/SCR-AH-183/BC230TX.JPG

In this coil set, the neutralizing winding- "C" on coil 121 -
was open.  I have about 20 TX coil sets 
(some will be offered for trade shortly).
So far, I've found four of them 
with open neutralizing coils. 
Winding "C" is on the small bobbin mounted inside
the plate tank coil (the one with the tap wheel).
Getting it out for and "autopsy" was a little tricky;
you must remove all the solder from the crossed
wire pieces used to mount it and remove them 
gently or the thin ceramic coil form will break.
I found it wound with fine wire which had
become very brittle; it had opened in several places.
I didn't see any corrosion, nor do I see an obvious 
path for a high voltage to burn the wire, but under magnification,
the open ends look black.  The wire crumbled into many 
pieces with handling.  For the 3-4 MC coil set,
the form had 21.5 turns on it.  I rewound it 
and it now works fine.  
So before you try tuning up, be sure to check 
the coils in your set for continuity.

73 DE Dave AB5S