[R-390] Dead R390A Need HELP

[Craig C. Heaton]

Good Morning Tom,

You have come to the right place. Just about everyone on the list has played
with these beast for some time. Going back through the archives and reading
earlier posts will help with issues. I don't think there is anything new
under the sun with R-390A's that hasn't been solved with this motley group.

Do down-load (and print) the Y2K manual, it might be in a second revision
and is 312 pages loooonnnng. It is a must read!! There are several sites
where it can be found, a search on google is a step in the right direction.
Most of your future issues can be solved with a VOM of sorts,(DMM, VTVM,
Dual FET-VOM,etc.)sig-gen(URM-25D is referred to in the Y2K manual), and a
tube tester is sort of nice to have.

The issue of capacitors will of course start quite a ruckus here, there are
the replacers and keep everything original sides of the story. I let a
Sprague TO-6A decide which caps get to stay and which have to go. All of the
brown beauties in my R-390A were bad, poor, or no insulation resistance.
Several of the electrolytic were shorted and or leaky.

You haven't bitten off more than you can chew. The R-390A was the first
receiver I've ever worked on. The Y2K manual will take you through every
step. I think the only thing missing in this document is a step by step
(with pics) description assembly of the gears. It can be found elsewhere on
the web, I can give a URL if needed.

I'll take a guess the receiver from Fair might have been modules put
together for a complete radio. It has to be in mechanical alignment before
an electrical alignment will bring things together.

Got mine running in less than two weeks.

Keep'em glowing
73's
wd8kdg
Craig

-----Original Message-----
From: r-390-bounces at mailman.qth.net
[mailto:r-390-bounces at mailman.qth.net]On Behalf Of Thomas Guest
Sent: Thursday, September 22, 2005 3:40 AM
To: r-390 at mailman.qth.net
Subject: [R-390] Dead R390A Need HELP


Hi everyone,

I am new to the R-390A but do antique radios. I may have bitten off more
than I can chew at the moment but I hope that will change.

I picked up this set from Fair Radio (used repairable) and powered it up and
get almost nothing.

I have replaced the killer cap in the IF, the 8 ufd audio section cap, and
the electrolytic tests good at full rated voltages. Fuses are good. I have a
short antenna 20' hooked up to the balanced input with the other half of the
connector grounded to the chassis. The ballast tube is good. The brown
beauty caps in the set have NOT been replaced! I see B+ of 285Vdc at the
back panel fuse.

I have a Hallicrafters R-42 speaker (600 ohm input) tied to the set and get
only a faint scratching noise from turning the volume control.
No signals across the board on this set. The carrier meter deflects about ½
way (my meters are not the factory ones) and I get no deflection on the line
meter.

Problems that I did find was the VFO was not connected to the front panel
knob, & the rear terminal strip was loose and could have been shorting the
RF gain jumpers to the chassis. After fixing these issues still have the
same results.

Any ideas on where to look next?

Or is there a way I could inject signals into the set to prove out a section
at a time?

Thanks in advance.
Tom Guest





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