SP - 1970 - Cartridge (Cart) machine was the workhorse for thousands of radio and television stations. The RP/SP series were among the most popular of all cart machines. The venerable "cart" began its ascension to the standard for broadcast stations in the early 60's.
International Tapetronics Criterion 90-3 cartridge machines.
Schafer 903 Radio Automation System (circa 1974)
RCA 70-D Transcription Turntable-  This is the RCA Type 70-D, Model MI-11801,  Transcription Turntable with RCA Type 72-D, Model MI-11852  Recording Attachment. This piece of equipment was used in broadcast stations for playing records and for recording onto transcription discs for future playback.

(Courtesy of  Western Historic Radio Museum  Vintage Radio Equipment and Memorabilia  From 1910 through the 1950s P.O. Box 73 - Virginia City, Nevada 89440  Owner/Operators: Henry Rogers - W7HTR   Sharon Rogers - KK7EI  www.radioblvd.com )  R- Most ET's were 16 inch in diameter and required a large turntable and special needle to play.
Ampex model 351 reel-to-reel tape machine. The workhorse of the time.
Scotch brand reel to reel magnetic recording tape.
Electrical Transcription  (ET)
Technician cutting an ET (Electrical Transcription)
- The first automation systems came to broadcasting in 1956  when the first Schafer Automation System was installed at KGEE in Bakersfield, California. The
owner wanted to program his station all night long without a person being there.  The automation system included  a couple of Seeburg record player changers to
play 45s and several Ampex reel decks for commercial. 
KTRB's first transmitter.  A homemade 250 watts transmitter built by Bill Bates in 1932.
Engineers working on the construction of KBOX in 1949.  R- KBOX's first transmitter manufactured by Collins transmitters.
J.D. West (Lee Mackenzie) KEJC at the computer.    
KDJK production room control board in 1985
1948 control board built by Raytheon.
Automation system including two cartridge turntables loaded with carts. 
An old Rekokut turntable modified to play ET's by Gary Avey, Chico, CA.  Note the penny on the pickup arm for added weight.  A time tested method to help prevent skipping during playback.
Computer automation,  the standard today.
Broadcasting Equipment 1930's to 1990's
Cartridge and reel tape bulk erasers.
Mackenzie Repeater Tape Cartridge Machine
Schafer model 800 automation system (tube type)  in 1969 at KDTH Dubuque, Iowa.