Koyo KTR-1661 rectifier

[CarlQB]

Hi
New to Videokarma, but have been on AudioKarma for a while.
I just got this Koyo 8-band transistor radio for cheap.
I'm looking at replacing the electrolytics in the power supply and amp section. I have some basic electronic knowledge but this is my first radio. Probably not the easiest for a newbie but this is such a nice unit with a wood case I couldn't let it pass.
It runs on 6V, and has a 2-diodes rectifier as shown in the schematic. I understand how the rectifier works, but can someone explain the purpose of resistor R74, between the 120VAC and +6VDC ?
I don't get it!

Thanks!