Hey Joseph, thanks for reaching out!
I recommend going with the Greystone Built-In RV Microwave # 324-000106 as it looks to be the most similar both in power rating, and in size (19" wide x 13-1/2" tall x 14-1/4" deep overall dimensions, but 23-3/8" wide x 15" tall with trim kit).
Attached is a review video for your reference! view full answer...
Thanks for the picture! In order to recommend a replacement I am going to need some measurements of your Apollo Half-Time Convection Oven. The High Pointe RV item # HP99ZR you were looking at might fit depending on the cut out dimensions for your microwave. It measures 20-1/2" wide x 14-3/4" tall x 18-11/16" deep and has a trim width of 24".
If you could email me the dimensions or comment in the box below of your microwave or cut out I would be happy to make a specific recommendation for you. view full answer...