[HBR] HR-10 to HBR project

[Walt Hutchens]

> The S-meter is a mess.  It's Shurite-style but open construction with a
> blank black stick on face (the scale is on the plastic dial); the needle is
> oddly bent; it sits at about 10% with the power off (no sign of a zero
> adjust other than realigning the meter body with the dial) and it seems to
> hang sometimes.

As fixed as it can be for now.  After removing/replacing the meter the
needle is straight, the zero location is about 5% and there's no longer any
sign of a hang up. 

It does seem that the mechanical zero is a matter of how the meter assembly
is aligned with the dial plate.   But the various screw holes aren't
properly placed to allow this to be done accurately.   The new panel will
require a complete disassembly of that part of the set so that's the time to
solve that problem.

Removing/replacing that meter without disconnecting all the switches and
disassembling the panel isn't a fun thing to do.   Oh and don't forget
restringing the dial cord.

I noted that touching the mixer tube sometimes led to a 20 db variation in
signal strength.   Standard fix: reheat all the joints on that socket --
that one IS a mess.   After doing that, the set was dead.  Oscillator okay,
no mixer cathode voltage, no SCREEN voltage ... the 47k resistor on the
screen had been replaced, evidently using rosin in place of solder.   I put
in a new part and all the troubles disappeared.

The 1680.7 kcs crystal is bad.   Since these crystals are socketed, you can
test them in the set, one at a time.  The high crystal -- 1682.4 kcs --
works exactly as you'd expect, namely, a narrow high peak at the IF.   The
low one, however, gives a much lower peak and considerably off frequency.

Unless I luck into someone disposing of a radio in parts, this will
ultimately require another whole radio.   However that bridge can be crossed
later: It works well enough as it is to do the conversion project and that
can hardly take less than a couple of months.

The Heath replacement part price for those crystals was $5.   That's about
what they'd cost today, with adjustment for the change in value of the
dollar, if bought as custom items.  However they should be replaced as a
pair.

Maybe I'll ask one of the crystal manufacturers for a price.  They'd be
cheaper to ship that a whole radio!

I wonder what fraction of the "I don't know anything about this radio" items
sold on eBay are ever made operable.   They are always dead when received
and that story generally started when the original owner couldn't find the
problem.  

The new panel -- 15" wide, 7" tall -- has been ordered.  And the solder lug
needed to allow a solid ground of the filament circuit has been installed.
The next thing is an IEC C14 connector for the line cord, then, I think,
starting on the front end revisions.

Walt
KJ4KV