[R-390] Frankenradio gets its Front Panel Restored

Wed Apr 24 18:00:37 EDT 2019

Hi Ed,

Thank you!  I’m still learning, tweaking and finding issues but so far the radio is working great with all the mismatched modules.  I had a sensitivity issue that wasn’t evident in use, but showed up in stage gain tests.  I found a weak 6AK6 in the IF bank, replaced it and now the stage gain checks show proper diode load voltage at the low end of sig gen injection which is a good thing.  Right now I’m listening to Radio Guinea on 9650 kHz loud and clear.

When all is ironed out: a line out oscillation, ovens blowing a fuse, etc. I’ll do the full sensitivity check.  I don’t expect to be disappointed as I was seeing 3 uV for 10 dB (S/N + N)/N before the tube change.  Diode load went from -3.7 to -7 just with that and I haven’t tweaked in the IF stage to match the new tube (not that I expect much from that since I already aligned it.)

John

From: Ed Rafferty <dktedr at gmail.com> 
Sent: Wednesday, April 24, 2019 1:58 PM
To: jgedde at optonline.net
Subject: Re: [R-390] Frankenradio gets its Front Panel Restored

Hi John,  your radio looks great!  Im curious about how all the components are working together for you  today performance wise,  have you had a chance to evaluate the build yet?    

  Interchangeability of modules  worked well while  I was working on  the UHF bench (USN) with  ARC 51, and ARC 52 radios and others (HF),  some modules really performed exceptionally well,  and those (modules) would usually wind up on our bench unit  for swapping  out with  other radios  modules that came in for repair.  Module repair and tune up was a mainstay. 

 We usually had a pool of good working and repairable modules that allowed us to turn radios around quickly.  I worked with tube radios  up until about 1990, after that, it was all solid state. 

Just curious about  how your  radio  is acting for you .  

best regards,

Ed  N4MDA,  

On Tue, Apr 23, 2019 at 7:51 PM <jgedde at optonline.net <mailto:jgedde at optonline.net> > wrote:

Back together..  Lots of glare..

From: jgedde at optonline.net <mailto:jgedde at optonline.net>  <jgedde at optonline.net <mailto:jgedde at optonline.net> > 
Sent: Sunday, April 21, 2019 9:19 PM
To: 'r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net> ' <r-390 at mailman.qth.net <mailto:r-390 at mailman.qth.net> >
Subject: Frankenradio gets its Front Panel Restored

I call her Frankenradio since every module is from another manufacturer:
Teledyne, Motorola, EAC, etc.

I really had no desire to take the front panel off since it was in somewhat
nice shape, but since the restore was coming along so nicely, I couldn't
leave it be.  Stripped it, filled it, Alodyned it, Rustoleum Dark Machinery
Gray, and squeegeed in ivory acrylic paint for the engravings.  Didn't come
out half bad I think.  Not perfect but WAY better than it was.

Put in new orange drop and film caps to get rid of those paper punks in the
if chain, took apart the meters and cleaned them up (yes I know.) , full
alignment, AGC mods, audio mods, limiter mod, carrier meter mod, etc.  Still
a couple of electrical issues, but it nonetheless works very very well.

Pics attached.

Having fun.

John

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