The power supply schematic above is from the KIM-1 manual from 1976 (http://users.telenet.be/kim1-6502/6502/usrman.html#D). What is the purpose of the .47 and 1.0 ohm resistors and why do I not typically see them on more recent transformer/voltage regulator power supplies?

 

Reduce in-rush amps to downsteam capacitor, which is 0 volts on start-up),
until the capacitor charges up to operating voltage

 

Reduce in-rush amps to downsteam capacitor, which is 0 volts on start-up),
until the capacitor charges up to operating voltage

OK, makes sense, thanks. I wonder why they felt it it necessary for the 6502 board...and I really do not see them as a standard with many ps supplies. They also have designs showing GPIO operation of solenoids with no diodes.

 

Thee diodes in your diagram are rate at only 2 Amps & 1 Amp.
The 1N4001 Diode is rated at 30 amps max in-rush.
They experience a 16 Amp in-rush = ( ( 12.6 v x 1.4 ) - ( 2 x 0.7 ) ) / 1 Ohm

Newer diodes with a higher in-rush rating may not need "turn-on" limiting resistors
Also, the Capacitor ESR limits amps in-rush
I did not include Capacitor ESR in the above formula

There may be "built-in" diodes in the output stage of some IC's.

 

A lot of times they are wire wound "fusible resistors". You see these in audio amplifiers all the time.

In-rush current limiting is one use.