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TELEGRAPHY
Have a look at the WESTON ELECTRIC TELEGRAPH TEST UNIT ...
TG-5-B
WWII U.S. ARMY / NAVY FIELD TELEGRAPH SET
RESTORATION
This SKETCH is from the TG-5-B Manual ...
The WIRING DIAGRAM is in the Lid ...
There are Slots for ...
The LINE BATTERY ( 3_3/8" x 2_1/2" x 1_15/16" ) of 22.5 Volt
and the LOCAL BATTERY made of 2 x 1.5 Volt »D«-Cells
Because the original-sized battery is no longer available,
I made the LINE BATTERY-PACK out of RECYCLED Laptop Li-Ion-Cells ...
5 x 3.7 Volt = 18.5 Volt Battery with a polarized connector-pair works well.
The Picture of the closed Steel Box: W = 6_3/4" x D = 4" x H = 4_7/8"
and its PLAQUE ...
The RECEIVER RELAY was disassembled and not working:
... The missing SPRING had to be replaced & put in an Insulation Pipe ...
... It holds the MIDDLE CONTACT in place & "in force" by the SENSOR-ADJUSTER.
... To center the Middle Contact, the HOLDERS had to be bent !!!
After solderings, correcting wrong connections, cleaning contacts ...
The TG-5-B works now with the BELL ...
HOW THE BELL WORKS:
( picture shows idle-state )
A SPRING with a HAMMER touch CONTACT "X"
The Input-Current (over contact "X") activates the electro-magnets ...
this causes the HAMMER to chime the BELL ...
at the same time the contact "X" opens ...
the current is interrupted and the HAMMER swings back ...
... etc. ... until the Input-Current is switched OFF.
The Bell works, but not the "INTERRUPTER"!
Disassembling the "INTERRUPTER" showed...
Left Half is an EARPHONE - Right Half is a MICROPHONE.
Repairing the Broken Wire in the Earphone was a strait foreward job ...
... ( see below ) - TEST with MUSIC was successful !
But the MICROPHONE ( right ) needs further attention:
Opened ( with a metal sheet ) the Microphone's Diaphragm-Ring ...
... Added CARBON PARTICLES (from another microphon) & COTTON ... ! ATTENTION !
The AMOUNT of both and the TENSION of the DIAPHRAGM-RING
are VERY CRITICAL PARAMETERS !!!
A DIAGRAM of a MORSE TRAINER ( W.W.Diefenbach »Morselehrgang« 1956 ) left ...
... USED AS THE TEST CIRCUIT ... and the re-assembled "INTERRUPTER" Unit right.
After TRIAL & ERROR ... Now the »TG-5-B« works again - "YAHOO!"
PS.: Sometimes the "INTERRUPTER" needs a "Wake-Up!" KNOCK
Authentic WWII HEADPHONES were found in a Flea Market in Berlin ...
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... and its missing "ARCH" is home-made from WIRE-HANGERS! My "Morse Trainer" from the '50s will become the PARTNER STATION ... ??? |
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( A BUZZER works like the BELL )
But not as simple as thought !!! The loop current is under 10 mA !
A 3-mA-RECEIVER is made out of ...
... a "Polarized Relay", SIEMENS T.rls.63a
HOW A POLARIZED RELAY WORKS ?
( Adapted from SIEMENS / 1961 "Einf.i.d.Fernsprechtechnik", p.100 )
The MAGNETIC ACTUATOR is embedded in a PERMANENT MAGNET.
Without current, the actuator rests either left or right.
A POSITIVE current through the spool enhances the magnetic field of the
permanent magnet on its LEFT side and weakens it on the right side.
A NEGATIVE current enhances the magnetic field on the RIGHT side
and weakens it on the left side - and therefore
the ACTUATOR FLIPS to the OPPOSITE POLARITY and RESTS THERE.
( Polarized relays may have more spools for special control patterns )
HOW TO MAKE A RECEIVER RELAY OUT OF IT ?
(1st) Set its contacts asymmetrically to get a definite rest-position
(2nd) Connect all ( if ) windings in a row to have the maximal sensitivity
(3rd) A POSITIVE CURRENT flips the actuator, the CONTACT will be closed,
and now the receiver relay can be used in the rhythm of the Morse Code.
The WIRE DIAGRAM of the P A R T N E R S T A T I O N
for the » TG-5-B « ( see top ) WWII TELEGRAPH SET ...
... with a "Graetz Bridge" because the polarized relay is (+/-) sensitive!
Ready to entertain neighbor's kids with a "Real Telegraph Line"
A LINE BATTERIE for the PARTNER STATION out of RECYCLED Li-Ion-Cells ...
HOW TO USE THE »TG-5-B« AS A MORSE-TRAINER ...
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