[Boatanchors] RME-45 Tips

[Bob Groh]

Thank you for the list!  I've got a RME-45 on the restore list and this
will come in very handy when the radio makes it's way to the bench.

73
Bob Groh, WA2CKY

On Tue, Mar 21, 2017 at 6:40 PM, David Stinson <arc5 at ix.netcom.com> wrote:

> 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.
>
>
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