[link|https://www.ifixit.com/User/4647189/Gazz|@gazz92970|new_window=true], It would help if we could see the type of terminals on this capacitor, but in general any 50uF capacitor that's rated for at least 250 VAC will work. Here's a used one from eBay that's rated for 450 VAC that would substitute just fine.
[link|https://www.ebay.com/itm/255087221531|SoleusAir PE2-10R-32 Portable Air Conditioner Main Capacitor CBB65 50UF 450V - eBay]
Here's one from Amazon that will slip right in with no problems; the specs are pretty much exactly the same as yours.
[link|https://www.amazon.com/COCAPCO-250VAC-Capacitor-50x76mm-Listed/dp/B0BYZ6N5KS|COCAPCO CBB65 250VAC 50uF Run Capacitor 50MFD 50 uF MFD 250V AC SH B.P2/S2 50x76mm 40/70/21 UL Listed: Amazon.com: Industrial & Scientific]
Actually, forget the used one; here's a new one on eBay that'll work too.
[link|https://www.ebay.com/itm/334136519408|CBB65 Run Capacitor 50uF 50MFD 50 uF MFD 250VAC 250V AC SH B.P2/S2 50x76mm UL - eBay]
There are many others out there that are even cheaper, but they don't come right out and spell out the shipping right up front like Amazon and eBay do, so you'd have to factor that into your ordering. Just use this search string on Google and you'll find lots to pick from.
[quote]CBB65 SH 50uF 250VAC capacitor[/quote]
Here are the numbers you have to pay attention to:
* VAC rating has to be at least 250 or higher, never lower.
* uF must match; yours is a 5% tolerance meaning it can range from 47.5uF up to 52.5uF so get one that has that same 5% or lower tolerance; e.g., you can use 2% or 1% but not 10% or 20%
That should get you going; good luck and let us know how it all turns out!