[R-390] Re: new search

[Paul H. Anderson]

On Sun, 5 Aug 2007, Bill Hawkins wrote:

> Ralph,
>
> Don't go out of your way to get the autotune power supply, unless
> completeness is your passion.
>
> That supply ran four 391's with one large transformer and selenium
> rectifier. Output was 28 volts at 24 amps, IIRC. Don't think there
> was a filter capacitor. The power only went to the motor, through
> a marvelous switching system.

The original one is the PP-629, and was used to power the autotunes on a 
pair of R-391's and a CU-286 antenna tuner.

I have used 10A labmda 28 V DC power supplies to good effect for a single 
R-391.

> As Roy Morgan said, don't even think about tearing up all of those
> pot metal castings until you can turn the shaft by hand, or maybe
> with a six volt battery. An old, dirty receiver probably has oil
> and grease that is no longer slippery. Best to clean and relube.

I don't recommend using 6 volts - that will more likely just heat the 
motor and not turn it.  Make sure everything turns by fingers first.

The oil and grease turns to glue after 50 years, so you need to get it 
out.  I'm sure this depends to some degree on past maintenance and how hot 
the receiver has been getting since the last lube job.

> Ah, but don't take apart the stacks of sliding stops if you can help it. 
> Complex reassembly. And don't lubricate the clutches. They are supposed 
> to work by friction (or is that the 389?).

The clutches need to slide - the old sticky grease won't let them slip 
when they need to, and it will tear the unholy patooties out of the 
autotune driveshaft and gears.

> If everything turns smoothly as is, you may have a radio that didn't
> work and wasn't used.

Heh - I ran across a 67 EAC that was like that - very nice, but had a 
loose clamp deep in the RF deck that was why it was cheap.

> The MC and KC knobs do have the locking screws in the center, right?

Remember not to tighten these too tight - just a smidge tighter than 
finger tight is all it should take.

> I wish you a cheery Good Luck. You should know that saying that does
> not help you, it only makes me feel better.
>
> Bill Hawkins

Yeah, good luck - every R-391 deserves a great home and a tender 
restoration!

Paul