First off, welcome to AK. Secondly, no need to apologize for asking legitimate questions, that's what forums like this are for. Worst cast is everybody ignores you.
The Kenwood receiver is a really nice unit. A keeper, well-built and (relatively) easily maintained. My initial thoughts on the input selector not working are thus: on many amps of this vintage, Kenwood among them, the actual switch that changes the input is placed on one of the circuit boards, often towards the rear of the amp. The knob on the front is connected to the actual switch by a mechanical linkage. Sometimes it's just a long stick that connects the two, sometimes it's a flexible cable, it depends on the particular type of switch employed. Take off the top cover, I think you'll find that the mechanical link has become, well, unlinked and that the knob is no longer connected to anything. Hopefully it's just been disconnected by someone or has popped off, because if it's broken your likelihood of finding a replacement is pretty close to zero.
A time delay system is used to add a small delay between the time the signal is sent to one speaker (or driver) and other drivers. In concert setups where there may be a significant horizontal back-to-front distance between drivers, this is used so that the sound from all drivers reaches the ears of the audience at the same time, or as close as they can get it. I'd guess yours might have been used for some home-brew style home theatre system, perhaps to compensate for rear vs. front speaker placement or to simulate surround sound by adding delay to the rear speakers. If you want home theatre, buy a HT receiver with built-in DD/DTS decoder and mutlichannel amp, it'll do far and away a better job of creating a realistic surround-sound environment. The delay unit is probably still useful. Many have a decent crossover, and if you do ever have a multi-driver multi-cabinet speaker system it will correct phase distortion/cancellation.
The reverb amp has also largely been replaced with the HT receiver effects. Reverberation is reflected sound, like multiple echoes. It is reverb that gives us the sense of space in a large hall or cathedral. Your amp has the ability to adjust the decay rate of the sounds. I don't know anything of that model, but it's likely pretty primitive compared to the DSP models on the market today. Might be nice hooked up to a guitar amp speaker, one of those 500W full-range models if you happen to play guitar.
As far as putting together a decent system, if you're on a limited budget I'd keep the Kenwood 11 (I'd keep it regardless because it's much better than most amps you can buy today for under $500 MINIMUM). You will find that the biggest bang for buck in audio is speakers. Good speakers have at least 10X more effect on the sound than any other component at almost all price levels. Spend the majority of your money on good speakers, you've already got a good amp. You probably already have a CD/DVD player and some sort of iPod, you can add a turntable anytime.
Dave
