This is the best picture I've had on a 50s 21" set, I've had 60s and 70s 19 and 23" B&Ws look this good, but not the earlier ones (I think it's mostly that the CRTs are usually a bit week on the 21" sets I find).
I ordered 1 of these film caps:
http://www.mouser.com/ProductDetail/...pVP4v9aA%3d%3d
But searching around they also have them:
here:
http://www.digikey.com/product-searc...=0&pageSize=25
And here:
http://www.ebay.com/sch/i.html?_from...p2045573.m1684
There's probably other sources too. I couldn't find any non-polar electrolytics with that high a voltage rating, and had to go with those big film caps.