Techno Stuff
How They Work - Reflex unit
Inside the reflex unit
The unit has a grey metal shell in between two metal plates. The mystery for many people is what is inside the thing.
big time |
| remove the shell |
|---|
Removing the grey shell is easy. It's just sitting in between the two black plates by tension and there is usually a solder lug bent over holding it in (the solder lug is shown in the highlight circle bent up/away). Sometimes you may need to loosen one or more of the screws at the corners of the black plates if the shell is clamped in tightly, but usually that's not necessary. The simplest thing to do is remove the unit from the back door and then you can slide the shell out by pushing on the ends of it (its shape is three sides of a sqaure).
When the shell is off, here's what you'll see.
big time |
| inside the reflex unit |
|---|
No doubt you spent the weekend before last taking apart the differential on your land rover, so you'll immediately recognize what is going on in this unit. The main shaft the wipers are connected to is spun one way or the other by a bunch of gears.
What we really care about is the stop pin sticking out of the hub. This pin limits the travel of the main shaft. In the image, we see a bolt sticking through the housing from the left. I labelled it the "operator gaff bolt" because it can be moved around (bally thoughtfully provided a few holes to screw it into). Once the pin hits the bolt, the shaft can't rotate any further. This allowed the operator to adjust the reflex unit so it never reached the most liberal position. There is also a stop that prevented the shaft from stepping up beyond a certain point. It doesn't matter on big time, but on many games more wires and rivets are used on the reflex unit, and it would be very bad if the wipers turned so far that they started connecting rivets that should not be connected.
Based on where the gaff bolt appears to be on most games we've looked at, Bally probably put it in originally, and how they did it is not really a bad thing. In onse sense, what it does it limit the range that the reflex wipers can move. If the bolt is installed at the 3:00 position, the wiper range in big time is limited to around a 100 degree arc. Whether this is good or bad depends on how the wipers are positioned on the shaft, which we'll get to on the next page.
In rare cases, the stop pin gets bent and allows the wipers
to travel outside the range that they should.
