[Boatanchors] RME-45 Tips

[David Stinson]

One of our members wrote me about his RME-45
project, asking about things to look at.
I'm copying this here for general information
and in hopes others who have revived an RME-45
can help him with "hints and kinks."
73 Dave S.
--------------------------

1. Did you find a way to get at the caps and resistors around the 
converter socket (7J7). Looking at it quickly, they look 
completely inaccessible.

Most of the cap changes were done when I got
this rig. There were some errors I had to fix.
Photos of 7J7 base:
https://goo.gl/photos/RrYBwdNKuVqfH8r6A
https://goo.gl/photos/vCeKJ5Xgf43UAsNE9

At the base of that tube, I replaced one cap.
The other and resistors were still good.
I pulled the BFO shaft and used a thin
iron for the work.

2. Do you have any helpful hints?
Get the correct manual for your version of
the set. It's way helpful.

Carefully go inch-by-inch, top and bottom
and address every ground point you can
find. Give screws a little "tweak." Make
sure solder joints are good. Yes; it's very
tedious and if you do it right, it will take
a day at least. And it will pay you
excellent dividends. As time goes on,
I am finding more and more Hi-Z ground
points in boatanchors that cause baskets
full of problems.

Do not attempt to un-solder anything from
the band switch. I promise- you will break
it and you will be unhappy with your new
"parts" radio.  Clip the leads and solder to them.

As-designed, the B+ is way too high. This
one was like 360 Volts IIRC. It caused an
insulation failure in a RCA jack in the middle of
the chassis that had B+ on it.
Photo:
https://goo.gl/photos/N9GjucLJBQzGc7MX8
I removed the wire since I didn't use the jack.
But there's more phonolic in the set with B+
on it. My solution was to remove one side
of the B+ winding from the 80 rectifier and
tie the two 80 plates together, changing
it from a full-wave to a half-wave rectifier.
This dropped the B+ to about 225 Volts.
The transformer seems happy with it.
Set performance did not suffer and no
noticable hum in the audio.

The audio volume knob is also the "noise
blanker" control. You pull and push
the knob to operate the Noise Blanker.
The blanker actually works fairly well, though
it does reduce audio level and narrows the
response. But the "Normal" position is
with the knob OUT, and I'm forevermore
bumping the thing. I'm going to eventually
find a way to turn that around.

One of the reasons they built a pre-selector
for the rig is that it has a bit of an image problem
above about 12 MC. Hasn't bothered me much.
The rig is very nice for SWLing and AM phone.
A bit drifty on the high end but settles fairly well
after some time.

The dual tuning mechanicals have a problem with
wear to the gears that makes tuning on the
high bands "tricky" if you're afflicted with it,
and I am. One of the guys said there's a
"trick" you can do, turning one of the gears
around to engage an un-worn area of the
shaft. I haven't attempted that yet since
I'm not trying to get DXCC with it, just listen
casually to AM and SWL. I got the matching
speaker at a local auction and like the way the
set looks and sounds.
https://goo.gl/photos/LbSaKwnLPHHMpjqz6

I didn't have to touch the crystal filter, and
I'm glad. I'd probably have munged it.
It works pretty well. I was impressed.

You might want to put a couple of
diodes across the meter to protect it.
You aren't likely to find a replacement.

Align carefully according to the manual, but
don't expect the big bandspread inner dial
to match exactly. They almost never do,
especially if your tuning gears have the wear
noted above. It's never going to be an Icom.

The sloooooow tuning can be a little annoying,
but you'll appreciate it on the higher bands.
Sensitivity on higher bands is much better
than a Hally-Scratchers or Hammer-Head.

Off/On switch being on the TONE control
is kinda odd. TONE does work well.

If it doesn't come with a fuse holder in
the transformer primary, I'd put one there.
Mine had one already. Haven't looked
at the value but probably something like
a 2 or 3 Amp slo-blow.