If you came out to monthly EARS meetings
http://www.ears-chicago.org you would have already learned proper pro audio parlance.
Meetings are usually the last Tuesday of each month. Each month we meet at a different studio to visit, conduct business, and have beer and snacks.
This month's meeting is at Delmark Records.
EARS Presents: A night at Delmark Records & Studio
Wednesday June 28th, 2023 at 7:00 pm
4121 N. Rockwell St. Chicago , IL 60618
(Street Parking is available)
Unless you're talking about a quad 4 pin xlr connector, calling something "pin 4" is not correct.
Tying pin 3 to a
chassis ground (that is the correct term) is far from a universal practice. Some mic manufacturers recommend it many others do not recommend it.
In any case, with the Sony mic you have no access to any pin 4.
If your Sony mic has hum then either the mic cable has become defective, was never wired right in the first place, or your input on the
console / interface has lost its ground.
To isolate the problem, change one thing at a time. First try a different cable. If the hum goes away with a different cable you know that it was the cable at fault. It can be repaired.
Then try a different console input. If the problem goes away, the other input that you used is bad. Make a repair in your tech shop.