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Premier Radio Company
Los Angeles, CA
(model unknown)
Circa 1925
This has been one of my projects
sets that I was ready to offer as-found. I first checked the
audio transformers so I could state their condition and found
all three were original and good! After a closer
inspection of the chassis and front panel, I concluded this was
a very unusual, rare and interesting set. So I decided to
restore the electronics.
My Restoration Details:
1) The windows in the two
vernier dials where poked out and the paper scale behind was
damaged. I removed them and made new *scales and windows.
2) The voltmeter stuck
around 3 volts, it too was removed and re-built.
3) The battery harness had
rotted, so I made a new one with old style, cloth covered wire.
4) There were a number of
loose connections due to the way the set is assembled. many
connection are secured with nuts and bolts and over he years
many were loose. I tightened all of them.
5) The filament control was
broken and I replaced it with one of the proper vintage and
style.
6) Checked all the tubes,
replaced two.
7) Final inspection, a good
visual, inspection all component and wiring connections. With my
VOM, a resistance check was made to make sure there were no
shorts between the B+ lines, filament and ground. All OK. Next I
tested the original horn speaker driver and it worked loud and
clear.
Ready to Power up:
Using one of my
ARBE III battery eliminators, I
made the proper connections to all but the "C" supply. I left it
with the jumper in place eliminating the need for external bias.
Then I connected my 75' attic antenna, a good ground and turned
it on.
Tubes lit up, I tuned up and down
the dial, nothing else but silence. I got a nice 60 cycle hum
when I touched the grid leak resistor (which indicated the audio
section was working good) but silence returned when I removed my
finger.
Then with my trusty Fluke VOM, I
proceeded to make some voltage measurements. They were all as
you would expect to find for proper operation.
That left only one thing, since
the audio stages where all working, there must be an open or
short in the RF signal path. So I started with the plug in
RF coils. I had not noticed 'til now but all three RF coils
(actually transformers) plugged into a standard UX socket. I
removed them (one at a time) and checked for continuity.
Two of the three had an open in the secondary winding. Both in
the same place, right where the external wound green silk
covered wire went through the hole in the Bakelite coil form.
These were repaired, plugged back into their sockets and Voila!
- a station was present right where it was left set from the
previous tuning effort.
To my surprise, it tuned station
throughout the dial with equal volume at both ends with
excellent *tracking, this is most unusual in most battery sets
of the mid '20's.
When repairing the RF coils I
noticed what appeared to be just a black top, was actually a
badly faded label. Barely readable at first, but when wetted,
some faint detail was clear enough to scan and
re-master for re-reproducing (which
I so did). The new labels can be seen in one of my chassis
images.
Next, I replaced the 3rd audio
stage with a UX-112A and connected the appropriate bias for that
tube and the overall performance and sound quality improved.
Where I live, AM reception is not so great as I live in a bit of
a valley type area. One of my tests of a good sensitive radio is
it's ability to pick up a hard to get station in my area on the
low end of the AM dial (550 Kc to be specific). This radio does
so quite well, in fact, it's the first 1920's battery set that
I've had on my bench that would tune in this particular station.
In conclusion, overall this
is an excellent performing and easy to tune set but it's not
without some problems that I attribute it's design. For one
thing, it has a tendency to growl or howl if the volume
(filament) control is advanced too high. Of course, one sorta'
expects these old sets to make howling (or other) noises if the
controls are set to an area they do not like.
* the dial scales where
originally the log type (0 - 100 scale). When I disassembled the
dial assembly to replace the damaged scale, I discovered that
they had been updated with paper overlays calibrated in Kc (500
- 1500). I debated with myself as to simply removed the old
paper scales and put the vernier assembly back together with the
original log scale or re-do the paper. I choose the latter.
Additional Info:
This set has a small pull out tray (or table) below the front
panel that serves as a small desk style writing area. There is
room in the rear cabinet for the batteries. There is no info or
manual for this set, so I created an original style battery and
installation sheet and attached to the rear cabinet bottom
(battery area).
The 3rd audio stage is switchable
with the center switch label 5 -6. In the "5" position,
only 5 of the 6 tubes are used. The "6" position give an extra
stage of audio amplification.
The switch on the far left is for
antenna tuning, 3 positions allow for best reception. The far
left controls the bias of the 1st RF amplifier, the far right
control controls the filaments for all 6 tubes.
More pictures below (click
on to enlarge):
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