ID this receiver

[Alex Eisenhut]

Found this in my junk. Yes I hoard... 
It must be more than 30 years old.
It is obviously a pretty good analog receiver for a 27MHz RC toy. But what is confusing is why it's a module, why it has screw holes, and why the crystal is removable.

It isn't the usual all-in-one toy RC PCB but I don't quite recognize it as the usual "pro" Futaba-ish RC radio receiver of the 1980s/1990s analog era either.

Anyone ever seen something like this? What does it come from? It has no markings on the case or the PCB.

The transistor that is at the antenna is marked 901 with some squiggle. It's cool, but I don't recognize it. A 2SK901 is a power MOSFET.

I might power it up later but I'm in the middle of "sort and decide to junk" of all my ridiculous boxes of nonsense.

[themadhippy]

why the crystal is removable

so you can switch to another frequency  easily.In the uk the crystals were colour coded and you'd put  similar coloured flag on your aerial so other users could see at a glance what frequency's were being used.