[AMRadio] Re: R 388

John Lawson jpl15 at panix.com
Tue Jul 17 17:05:31 EDT 2007

On Tue, 17 Jul 2007, kk4tr wrote:

> Well Guys the Problem was easier than I thought it would be.  It seems that 
> when the last person to put the PTO in the R 388 Got everything right EXCEPT 
> lining up the endstop portion of the dial train with the Pto!!!  I used a 
> frequency counter as was suggested by one of the guys and discovered that the 
> PTO output was correct just a bit off   (2.75mhz to 3.75 mhz)  . I just 
> loosened the dial knob on the front side of the PTO turned it 1 turn clock 
> wise and I now have the proper positioning of the of the frequency display on 
> the slide rule readout. All that is left to do is center up the round khz 
> dial  and then do an alignment.  I want to take this opportunity to thank all 
> the guys especially John and Don and all the others for the valuable advice. 
> Without it I think the radio would still be in the corner gathering dust 
> while I tried to figure out what the next step would be.  Thanks very much 
> guys for the help.

      Even though there is an R-390 and 390A in the rack, I consistently 
use my R-388 as my 'daily driver'...  a couple of years ago the PTO 
developed a shorted bypass cap, so I took the opportunity to have the 
front panel and dial drum re-done by Howard Mills while I got the PTO on 
the bench and made it happy again.  When I re-assembled the radio, I got 
the Oldham coupler 180 degrees out of phase, and instead of stopping to 
figure out what was wrong, just slid the dial pointer over to 'correct' 
the error and put 'er all back together again...  of course the mechanical 
stops took over at the very high end, losing that last bit of travel, and 
the low end had no stops at all, endangering the PTO...  this also 
slightly misaligns the whole rest of the radio.

    So I futzed that back into correct alignment without having to R&R the 
front panel again... still, it was an easy mistake to do.

   Congrats on getting the Old Girl back in tip-top shape - what a great 
radio it is!   I've had mine for over 25 years...



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