| BC-348R
RECEIVER PARTIAL RESTORATION, OVERHAUL & INSTALLATION  The replacement, almost ready for installation. |
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| As
with all things, priorities change and what may have been on the top
of the list gets moved to the bottom; so many things vying for attention
& importance only to be shoved aside and hopefully not forgotten.
So it was in having an actual original working radio receiver in "Heavenly
Body". After many, many years it will finally come to pass. |
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| Not
too long ago a discussion about getting the radios working was brought
up again and the present receiver in the aircraft was inspected and
found to be horribly unsuitable, in fact it is doubtful that it will
ever be able to be restored to any suitable condition for any operation
other than static display or used for parts. Like so many of its kind,
they became surplus after the war and could be purchased very inexpensively
and used for Ham radio operation or for short wave radio reception with
a relatively simple conversion done to it so it could operate off of
your household electricity. In the case of Ham operation, many were
modified in various ways to "improve" them - some mods were
good and some less than good and the latter is the category to which
the present receiver falls into, which brings us to its replacement. |
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| The
replacement was remembered and pulled from a storage container. Absolutely
filthy on the outside, itself at one time also thought unsuitable, but
in this business one learns never to throw anything away - you never
really know when you might need that part again! After its initial inspection,
the replacement was found to be not only suitable, but 100% unaltered
and 100% all there, including the dynamotor! In fact upon opening the
case, as you shall see, it's just about as clean as the day it left
the factory. |
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The
first order of business was to get the case cleaned and touched up.
I thought the dirt would never end, it just kept coming and coming;
all 50+ years worth. A quick preliminary check of the circuits was made to make sure nothing was shorted out or was going to cause a major problem. Part of that process was to pull the dynamotor, inspect, clean, lube, then reinstall. Next was an inspection and cleaning of the interior and a bit of grease on the tuning gears, yes gears - no string or rubber bands floating around inside here, and a touch of oil in the bearing journals for silky smooth tuning. |
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Receiver removed from case. Rear view, power cables & position of Dynamotor. |
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Then
the 24 volt battery was connected for a live test fire. It worked just
like it's supposed to. Great reception and spot on with alignment, though
I ended up replacing one tube (the 991), all the others checked-out
as acceptable. A special thanks to Ed Richards, K6UUZ in making himself
available and in his guidance. |
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Now that all seems well, the receiver will get "exercised"
over the next weeks or so in order to reform and give a workout to the
capacitors. Nothing like getting "Radio Beijing" on a hot
Sunday afternoon! |
 Final check, all systems are a "go." |
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UPDATE:
(from my post
on the forum) Finally have it installed, at last we have an original
working BC-348 in the ship. Probably the only flying B-25 in the world
set up like it was. I had to adjust some of the routing of the wiring
for easier maintenance and to minimize any RF interference that might
be generated from the dynomotor. |
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If
after reading this, you are up for a similar project, you will need
a complete manual and it just so happens that they are available for
free and in a pdf format from http://bama.sbc.edu/
under "Military Manuals". Make sure you get the right one,
they all might look the same, but there are subtle differences
inside between the models. |
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