[Milsurplus] BC-375

[Jack Antonio]

Hi Ron and the group

A search of the archives for this reflector should
bring up some information on the BC-375, gotchas
and tips on getting it going. You might have to
go back a few years though, but they are all good
reading.

Keep in mind,, these rigs are happiest when
they are used as designed, the mods made to
make them more "ham-friendly" usually destroyed
the engineering and craftsmanship that made them
work in the first place.

There is a downloadable manual on the kg7bz.com
website. If you don't have a manual, get one and
read it before starting work on the radio.

To summarize the things to look for,

1. The high voltage fuses have a tendency to
fail open over time.

2. Contacts on the keying relay can oxidize,
manually operate the relay and check for
continuity. (WIth no power applied)

3. The power resistors can also fail open over
time. Check all these.

4. All the tube biases are developed from
the PA grid current. A bad oscillator tube
or PA can result in no grid current, ergo no
bias, ergo lots of current draw, ergo blown 
fuses.

5. Neutralization is vital for a clean signal.

6. As designed, the B+ voltage is continuous,
not keyed. So even with the transmitter in
standby, there is still 1000V floating around
inside,  BE CAREFUL!

7. The filament circuit is a little complicated,
get the manual and read the section on setting
all the jumpers in the filament circuit.

8. When firing it up, apply just filament voltage
first, make sure the tubes all light, the filament
voltages are all OK, and the keying relay pulls
up OK.

But when you're all done, it's a fun rig to
put on the air.

73

Jack

Jack Antonio WA7DIA
scr287 at sbcglobal.net


----- Original Message ----- 
From: <TVComlGuy at aol.com>
To: <milsurplus at mailman.qth.net>
Sent: Monday, May 31, 2004 9:10 AM
Subject: [Milsurplus] BC-375


> I just picked up a very nice BC-375E in the box along with three TU's and  
> the antenna tuner.
> Reading in my Surplus Conversion Manual it says that you shouldn't try to  
> put these on the air due to their instability.  Is this true?  I would  like to 
> get this on 80 and 40.  Does anyone have a schematic for a modern  power 
> supply to supply the voltage for it or even an original power  supply.  I have a 
> couple of Heathkit HP-23's that supply 700 volts at  250ma.  Would this work for 
> the B+.  Any help would be  appreciated.
> Thanks,
> Ron, KB0WAR
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