by James_Douglas »
Sun Oct 13, 2013 5:32 am
OK, I think I have a handle on the "Big Caps". I found this write up on the net and it helped a lot.
Also, I got a WSR5-L6 schematic online and it shows that .005 MF-1000V capacitor in my WSR3 that is not on the WSR3 schematic.
My only question now is on the Mallory cap, since it has three posts with wires on it, what are the values?
Thanks all, James
*****************
Examining Wired Selection Receivers in my collection,
here's what I found:
WSR-3 (used in the M100A ONLY) Has a large capacitor
next to the 2050 tube, outside the stepper cover. This
is the motor capacitor, and was only installed on the
WSR-3 receiver for the M100A. It also has the
cylindrical cap under the stepper cover [Mallory type WS on my M100A -James Douglas], and the
square rectangular one mounted on the inside wall of
the receiver.
WSR-5 (used in the B, BL, C, G, W) Motor cap has been
moved to the Mechanism starting with the M100B. WSR 5
still has the cylindrical cap inside the stepper
cover. It also has the cylindrical cap under the
stepper cover, and the square rectangular one mounted
on the inside wall of the receiver.
WSR-7 (used in the R, J, JL) No cylindrical cap in
stepper area. It retains the square rectangular one
mounted on the inside wall of the receiver however.
None of the receivers in my present collection have
phenolic stepper plates. Although I've seen them
often, it never occured to me that some WSR-3's and
WSR-5's may have them, while others dont.
I'm puzzled that you have a WSR-5 receiver with no
square rectangular cap underneath. What is the serial
number? I can't say I've ever seen a WSR-5, or ANY WSR
without it. But as I am beginning to understand,
nothing was consistent.
Here are other things that don't seem consistent to
me...
Stepper Mounting Plates: Some are metal, some are
phenolic. Common sense would say that early machines
should have metal, later should have phenolic. But
this doesn't seem to be the case. Ron has suggested
that the phenolic was a wartime thing (along with the
cardboard stepper and CCU covers mentioned next). My
M100A's WSR-3 has a metal one, and while I have worked
on WSR-5's with phenolic ones, I have several WSR-5's
with metal stepper plates here in my collection.
Stepper and CCU Covers: Same issue.. My M100A has
original metal ones, but I've seen later machines
(even up as late as G's)with cardboard ones that I
feel were original. I cannot say I have ever seen a
WSR-7 (R, J, JL) with anything but metal covers.
My assumption with the above two puzzles is that the
metal parts must have come first, then Seeburg must
have switched to phenolic stepper plates, and
cardboard stepper and CCU covers at some point because
they were cheaper, but soon realized they were not
holding up, and went back to steel plates and covers
again.
Which brings me to the lower back doors covers. All
M100A's had a metal back cover plate, and my M100B has
what I feel as best I can tell an original metal back
plate as well. I have never seen a C, G, W, or R with
anything but a Masonite back cover. So I am assuming
that all A's and probably most if not all B and BL
models had metal back plates, then Seeburg switched to
masonite with the C, G, W, and R. Perhaps they
switched to Masonite panels at some point around the
BL or a the onset of C production, and then realized
that they kept getting damaged, and went back to metal
back panels with the 100-J. All 100-J machines had
steel lower back covers.
Remember a glaring case of this changing design and
materials issue was when Seeburg went to printed
circuit boards with the K, KD, and L models of 1957.
After experiencing technical issues, quickly they went
back to wired chassis and Amphenol plugs in the 1958
models 201, 161, and 101.
Another thing Seeburg never explains well is the
amplifier type MRA-2 of 1949. This amplifier's
schematic appears in the service manual for the M100A,
and is referred to as a directly compatible with the
MRA-1. The only difference appears to be that it uses
military numerical tubes in place of the 6V6's. A
label pasted on the chassis of an MRA-2 in my
collection reads: "The Hum Balancing Control located
near the 5U4 tube should be adjusted for minimum hum
if tubes are changed. This amplifier is
interchangeable with the MRA-1"
So what amplifier came stock with the M100A? an MRA-1
or an MRA-2? I am guessing all M100A's left Chicago
with an MRA-1. My MRA-2 came out of a M100B, I do not
know if it was original to it. All MRA-2 amplifiers
had the same blue nameplate on it printed MRA-1,
however the "1" is overstamped with a larger "1". Mine
is also using standard 6V6's, with the military tubes
long gone. So the existence of the MRA-2 amplifier
remains another mystery to me.
*****Here is a sidebar about 100-J machines I always
found interesting. How come some 100-J machines have
green tonearms, green record strippers, with green
plastic stripper plates; while some have red tone
arms, red record strippers with clear plastic stripper
plates? The second mystery to me is the often
publicized artists' conception of a 100-J with an
incorrect woven cane veneer pattern on the side. in
this rendering is some type of prototype reverse
screened/single strip Record Now Playing indicator
that was not produced until 1963 with the LPC-1.
Additionally some of the 100-J glamour shots have
german writing on different parts of the machine
instead of english. I always considered the HF-100-R &
100-J machines to be the height of Seeburg development
and design, never again equalled. After 1955,
everything seemed like a design compromise, and things
got too complicated. *****
John D. Rutoskey
Automatic Music Machines
Baltimore, Maryland