April 7, 2010 Radio Work on The B-17 Project

Had a very productive day at the Mighty Eighth Air Force Museum today.  Carroll, Steve, and I arrived at 2:00pm.  Carroll brought along his new 28 volt power supply so that we could test the DM-28 Dynamotor that we serviced last week.  While we had the dynamotor out of the radio chassis, we applied the 28v to the input side of the dynamotor.  It works!!  The motor immediately started turning at the 4400 RPM to step up the voltage to 220v plus.  Carroll tested the output voltage with his multimeter and it was right on.  Wow, were we excited!  We let it run for a while then we took off the endcaps so that we could inspect the movement.  Everything looked great.  We then disconnected the power and re-installed the dynamotor into the radio.  Got it secured in the chassis and connected the wiring.  Then we applied power again to test the receiever under load.  As the dynamotor spun up we watched for smoke.  Nothing fried or blew up.  Yippie!  We let the radio run for about two hours since it probably has not run for decades.  I sure love the sound of that dynamotor.

While we let the radio run we turned our attention to another receiver that Kevin-KW4B donated to the project.  It's a very nice R-26 Command Receiver that operates in the 3 to 6 Mcps range.  Carroll tested all of the tubes with his tube tester and they all checked out fine!  Good stuff.  We need to get a dynamotor for this one and we should be good to go.

Next week we'll install a new tube in the BC-348 to replace the bad one we found last week, then we'll perform an alignment on the reciever using some more of Carroll's test equipment.  Once we're done with that then the next step will be to hook up an antenna and see if we can receive anything.  That will be fun.

To see more pictures and short videos of our work visit our club Facebook page called:
Coastal Amateur Radio Society