AN/URT-3 RF Oscillator - Restoration Page 2

The RFO is a tube-type frequency synthesizer based on multiple oscillator, multiplier, divider, and mixer modules. The frequency can be set with 10 cps resolution either manually by 7 knobs (XX.XXX XX0 Mc) or remotely by dialing up one of 10 channels, each set with 7 miniature rotary switches.

Switch wafers within the modules are activated by Ledex rotary actuators, advancing one switch position per pulse. The actuator keeps pulsing until the switch shaft gets to the position it is seeking. The manual knobs are on the same shafts as 7 of the 21 Ledex units - the knobs are used for manual control and the Ledex actuators for remote control. The other 14 actuators are slaved to the 7 masters - turning a knob may make 4 or 5 other Ledex units start seeking a new position. All in all, it is a marvelously complex design! (Note - the closely related AN/SRT-14 design does not have remote control so knobs and module switch shafts are slaved together with multiple small "bicycle chains")

The RFO is built around a central chassis with removable modules mounted on right, left, top, & bottom sides. The front panel is also removable. This page shows removal of the modules for cleaning. RFO page 1 shows the initial cleanup of piles of mouse poop on the top of the unit. This page shows removal of the modules for access to the main chassis. RFO Page 3 shows cleaning and reassembly.

RIGHT SIDE
rfo-18.jpg (59182 bytes)
right side module shaft couplers		 rfo-19.jpg (60145 bytes)
right side module shaft couplers		 rfo-20.jpg (59955 bytes)
right side Ledex rotary actuators		 rfo-22.jpg (57333 bytes)
Right side modules removed to access interior cover.
rfo-23.jpg (61670 bytes)
Right side interior cover removed -
Another mouse nest!		 rfo-24.jpg (63744 bytes)
Right side interior cover removed -
Another mouse nest!		 rfo-26.jpg (62172 bytes)
Right side interior cover removed - 		rfo-27.jpg (62187 bytes)
Right side interior cover removed -
rfo-28.jpg (61576 bytes)
Right side interior cover removed - 		rfo-43.jpg (61305 bytes) rfo-44.jpg (61624 bytes)  
rfo-45.jpg (58294 bytes) rfo-46.jpg (62272 bytes) rfo-47.jpg (61873 bytes)  

LEFT SIDE
rfo-32.jpg (59025 bytes)
Left side modules		 rfo-33.jpg (59280 bytes)
remote dial-up stepper switch		 rfo-34.jpg (59374 bytes)
Ledex pulser motor/switch at top		 rfo-35.jpg (60884 bytes)

TOP
rfo-30.jpg (60537 bytes)
Top modules		 rfo-36.jpg (59051 bytes)
after removal		 rfo-37.jpg (60036 bytes)
cleanup needed		  

FRONT PANEL
rfo-41.jpg (64475 bytes)
Front Panel removed		 rfo-40.jpg (61071 bytes)
Chassis behind front panel		 rfo-39.jpg (54953 bytes)
front panel and chassis
rfo-42.jpg (64662 bytes)
remote frequency select switches -
10 channels XX.XXX XX0 Mc

Modules awaiting cleaning
rfo-48.jpg (60121 bytes) rfo-49.jpg (61203 bytes) rfo-50.jpg (55392 bytes) rfo-51.jpg (61833 bytes)

Chassis awaiting cleaning
rfo-01.jpg (55589 bytes)
Right side & Top		 rfo-02.jpg (53533 bytes)
Top & Left side		 rfo-03.jpg (54174 bytes)
Left side - coax switch box is not removable		 rfo-04.jpg (50452 bytes)
Left side - channel stepper and Ledex pulser