[Milsurplus] R390

[Gordon Smith]

HI Mike,
Here is a basic discussion on the differences between the "A" and 
"Non A":  "The R-390A was a cost reduced R-390. To do this, they 
reduced tube count from 32 down to 26. One stage of RF and 4 stages 
of IF, rather than 2 stages of RF and 6 stages of IF. Also, the "A" 
has a simpler, more conventional power supply without the regulator 
tubes.<P>The biggest difference is that the "A" has, with very, very 
few exceptions, mechanical filters."

Discussion can be found here: 
https://www.antiqueradios.com/forums/viewtopic.php?t=5427

So you should be able to find out quickly what version yours is

73, Gordon KJ6IKT


At 08:55 AM 8/23/2020, mike christie via Milsurplus wrote:
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>I've  inherited  an R390 it doesn't have a data plate on it so I 
>can't tell if it's A or not.  I have it up and running but the 
>sensitivity is really bad on all bands.  I can hear WWV on 10 and 15 
>Mhz but not really strong and I went to the Amateur bands and I 
>could hardly hear anything there either.  All the controls are 
>working such as the BFO, limiter, Broad & Sharp,  RF gain etc.  All 
>the tubes are lit and I am getting background  noise. I've switched 
>between antenna inputs and I get the same results.  When I'm tuned 
>to WWV the Dial is correct for at least on  10 & 15 MHZ. Also I can 
>hear when the antenna is plug in also.  So since I'm getting back 
>ground noise on all bands,  I'm thinking I've got some bad tubes at 
>least on the front end.    I've used one when I was I in USMC so I 
>know what their capable of.
>Can some give me some pointers as to what maybe the problem?
>Thanks
>Mike
>W1ZFB