Nitro Ground Shaker - switch wires clipped?

[vinito]

I was putting the playfield back together on this NGS and discovered that a couple of the leaf switches had tabs with a sharp "tit" on them, like a wire was clipped off.

Further inspection and comparing to other leaf switches revealed that it looks like somebody clipped the diode off, which basically leaves the switch dead.

#1) I am assuming this is some hack from a previous "repair", but there's the outside chance it was a design adjustment after-the-fact. There are two like this. Both are behind the rubber bumpers in the upper-right corner of the playfield - one is just to the right of the "B" rollover and the other just to the right of the "D" target. These are supposed to work, right?

#2) The schematic indicates that switch diodes are IN4148 and I might have some, but I wonder if some 4004 diodes will work as well (I have a ton of those).

Any help on these two questions is appreciated.

Here's a couple pics of what I'm looking at:

Good switch:



Clipped switch:

[Ballywannabe]

ALL playfield switches should have a diode on them for the NGS - my guess is that someone thought they were clipping capacitors off, which is OK but means the switch may not always get read on fast hits.  A 4004 should the trick if you have not got any of the 'faster' diodes.

cheers
Ian

[vinito]

Thanks. I figgerred they ought to be hooked up.
The diode being clipped out actually breaks the circuit, so those switches are dead without them. I'll try to find the right ones to put in there. I might have a couple.... somewhere in the pile 

Man, a lot of parts sure get accumulated in short order. I have little electronics stuff scattered everywhere now.

[Strangeways]

As Ian pointed out, they are "dead" switches.. 1n4004, or 1n4007 will work fine..

Ops used to snip the capacitors when the switch matrix was playing up, not diodes - so it does seem strange