I'm not sure if this information is what you're looking for or not. Eventually, I got what I needed. As I mentioned, the converter that was in my popup originally included 3 DC circuits with fuzes, a circuit breaker for the 110 volt circuit, and an on-board GFCI outlet. When the unit began to fail, I assumed I'd be able to find something functionally identical. What I ended up finding was not the same, but it was close enough. I got a WFCO Ultra III 30 Amp Power Center - 8700 Series.
The first thing I needed was information. While trying to find a replacement part, although the products I was looking at on the internet were, in fact, appropriate for me, I couldn't actually determine that. We always camp in places with electrical hook-up, and I really had no other need for a battery. However, nearly all of the product specifications that I saw were focusing on how well they charged the battery - I couldn't actually determine clearly if they provided the AC & DC things I needed. So I finally ended up going to a brick-and-mortar store (a fair distance from my house).
The guy at the store knew the answers to my questions. (1) No, I did not need a battery just to make the electrical system happy. (2) The new converters don't actually provide an on-board AC outlet, but no big deal. (3) He asked if I had A/C -- no, but it is a possible future addition. (And a few other details) Based on that, he recommended the 30 amp AC / 25 amp DC model.
Also, the new one has room for 2 AC circuit breakers, but they aren't included. So he sold me what I needed for that as well.
I'm sure I paid more than online. And if I had been able to get the information I needed online, I may not have selected this specific brand. (In fact, I have since found some poor reviews on this model). But it's fine, the guidance was worth a lot to me.
Physically, it fit pretty well - only slight modification to the original opening. Regarding the wiring, I had taken a video as I disconnected the old one, and that helped a lot as I wired the new one. And since my old unit had a GFCI outlet on board, but the new one has no AC outlet, I merely replaced the first outlet in the circuit with a GFCI.
When I powered it up, it worked perfectly. The new one is all new technology -- much lighter than the old. And it is quiet -- no hum at all. When I turn on enough lights to consume some level of amps, a quiet cooling fan starts up.
So far, so good. We haven't actually gone camping yet.