Hi Kitty!
If I may chime in.....
"If you set the drain knob to "wash drain" will the spinner still drain ?"
Anyone can correct me if I'm wrong on this, but it seems to me in both of my A50's that it is a diverter valve between the two tubs.
However, it seems that priority is given to the wash tub.
I once forgot to change the control back to spin drain when loading a soapy batch into the spinner. The water level that the load created in the spinner plus the detergent sudsing up caused the spin tub to never reach full speed.
The water was spraying out the hose into the sink, but I couldn't understand why I could not "hear" the spinner reach full speed.
Stopped and checked a few times and the outer spin tub was still full of water and sudsing up even more from the action. Checked it 3 times. Then lifted the lid for the wash tub and noticed nearly all the water was gone.
"The light bulb went on".
I checked the dial and sure enough, I hadn't switched from wash/drain to spin/drain.
So really, it will drain the wash tub, won't drain the spin tub, will never reach full speed, and could "cut-out" due to overloading the motor.
Which brings me to your first question and one that many have replied to.
"Why can't you spin-rinse?"
Although others have offered their opinions and/or suggestions, I once overloaded the 1980 A50's spin basket during the brief time I was able to use that machine.
And ya know what happened?
The motor "popped"!
And it rendered the spinner completely useless. It was several hours before it 'reset' itself and worked again.
So I learned a lesson, and maybe some of you A50 users/owners/collectors have never experienced, but the spin motor will CUT OUT and reset itself if you overload it.
And that's Maytag dependability for ya!
Even if the user overdoes it, the machine will stop, rest and come back to you when it's darned good and ready!
Hope that helps.