Matt,

The bit in the aluminium box appears to be a solid state rc relay. This is similar to the ones on the team delta web site and i bet if you take it out it says team delta on it.

http://www.teamdelta.com/products/prod2.htm

The three wires going into it on the right hand side of the photo are the rc leads. It's not unusual for these to go to a connection box where they're soldered or a pcb with some suppression capacitors on it. You don't see them so much now as the need for suppression on 2.4ghz is less.

The two outgoing red wires from this on the left are the switched circuit. These pass through the relay on the left which is a 'buffering relay' designed to take the load of the coils on the valves. Trace these back and i bet the just create a loop between your live and negative terminals (again at this age they probably take a really arduous route through various PCB's etc which are now realatively unnecessary due to the new rc gear.

The relay on the left seems to operate the valves. I suspect the blue wire coming out is a negative and the other two are switched circuits (mainly because the blue wire seems to go to both valves.

Trace all the wires out and see where they go but it actually seems fairly simple.

It's a good enough system and you don't need to replace it unless its failed.

Test it without the roboteq connected if you have a receiver battery.

Gyro I would lose and just learn how to drive it without. Never used one, never seen the point and the only one i tried to connect made the speed controllers do strange things. At least do your testing without it and then connect to see if that's the problem.

I see no bec there so you may be simply relying on the bec from the roboteq. It may be ok on 40meg but they tend not to be man enough for a 2.4ghz set and cut in and cut out so best to put one in or use a 4.8v receiver battery. (team delta stuff does not do 6v batteries very well)

Andy