[R-390] Re: R-390 power plug.

Wed, 10 Apr 2002 10:00:00 -0700

David,

In Korea in about 70-71.

I had a radio intercept van. It had 8 R390 receivers.
4 racks two receivers each.

The whole van ran off the 24Volt generator on the
truck's gas engine, or off a "small" gas powered
DC generator.

The engine generator was not a stock item.

Those 8 receivers had the dynamotor power supply for the R-390
power supply. Our run time on the DC for the van was a little as we could.
Once a month we did a 1 hour maintenance run.

When the R390 came out of the van into the shop, we dropped a
110 Volt AC power supply into them and did the maintenance that way.

We would pop the dynamotor brushes and look at wear.
As our run time was less than an hour per month, when we
looked twice a year the parts looked like new to us.

We had a spare receiver with supply and 1 spare supply.

At the school house at Ft Devens in 1969 I saw one
R390 with the power supply. It was a show and tell unit
only for education. there was no 24 volts to run it in the
building.

The Ft Devens School House R390's were all AC power supplies.

All the van stuff I ever seen in NAM, Korea, and Devens was all
AC except for the one van.

All the filament strings added up to 24 volts (2 x 12.6 or 4 x 6.3)
the dynamotor only had to make up the B+ (25 watts)
Some one thought the dynamotor would be "cleaner" than
the vibrator power supplies used in the battery radios of the 1930's.

So these things were rare back in 1970 just to start with.
Pop an add up on E-pay for a kilo buck and see if you even get an offer.

Roger. KC6TRU.

                    David Ross                                                                                         
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                    an.qth.net                                                                                         

                    04/09/02 06:53 PM                                                                                  
                    Please respond to                                                                                  
                    ross                                                                                               

390 folks -

  Jim Temple mentioned DC power operation with an R-390...

  There is a dynamotor power supply for the R-390 & R-391 -  has anyone
ever seen one? I'd sure like to find one...

best
Dave Ross    N7EPI    [email protected]
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