When working on the R-390A be sure and replace C553 on the IF deck. This
cap blocks DC to the mechanical filter which may be destroyed if it
fails or leaks. I would put that task #1 on any inspection and
especially prior to resale.
k4che

On 7/23/2024 3:19 PM, Ray Fantini via Milsurplus wrote:
>
> I have worked on a boat load of R-390A receivers but only two R-390
> receivers. Never bought the cost reduction thing because as you say
> the changes on the cost verses the added reliability and ease of
> maintenance on the “A” make the early version of the R-390 a bit of a
> pig in my book. You can do a mechanical alignment on the “A” with ease
> but forget about it with the non A, recall something about the
> regulator tubes being they were some weird twenty four volt filament
> and were only ever used in the 390 so in Addition to all the heat they
> added they were hard to come by. Recall that I saw one 390 modified
> with an additional filament transformer so it was able to use regular
> 6080 regulator tubes.
>
> Weird thing about the R-390A, a Collins version will sell for twice
> the money of a non-Collins. The last R-390A I sold was only able to
> get $325 for it and that was one hundred percent working with covers.
> The issue was it was built by Motorola and not Collins, think I would
> have easily gotten $500 for a Collins radio although there is no
> difference.
>
> Think I paid about $200 for that radio but put maybe ten hours work
> into getting it right so unless I can pick up radios for $50 to $100
> don’t think I will be doing any more R-390A receivers to resell.
>
> Ray F/KA3EKH
>
>
> ______________________________________________________________
> Milsurplus mailing list
> Home: http://mailman.qth.net/mailman/listinfo/milsurplus
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[email protected]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html