Marantz 3650 preamp filter push button knob

[IGSTER]

I lost the filter push button knob on my Marantz 3650.
I was wondering if anyone could help me out as to where I can pick one up.
My knob has a round female opening.I see alot of square openings but for some reason I cant find one wirh a round opening.
Any help would be appreciated.

 

[wlhd1610]

I had a 3650 in for a restoration a year or two ago with a missing pushbutton cap.
The owner and I searched eBay,and various other places and came up empty.
It's a very rare piece.
My last resort was to machine down a longer 2330b pushbutton cap and fit it on the black sleeve.

Bob

 

[IGSTER]

Bob,
Thanks alot I really do appreciate the reply.
I was hoping for better news.
Hopefully someone has a 3650 they are parting out.
I included a couple of pictures of the missing piece.
I will be using your tip until I find one.
Thanks again