Classic Bally / Stern
These adapters will allow you to use LED's in your classic Bally / Stern's with -17, -35, M-100 and M-200 CPU board sets.  
No soldering, no crimping, no tools required.  
It converts your existing main lamp driver board to be LED compatible so you can use any pinball LED's on the market.
 
As pinball machines can sometimes change hands pretty rapidly, this adapter set is just as quick and easy to remove.  No permanent modifications are made, so it preserves resale and collectability of very clean and original machines. 
 
ALTEK main lamp driver boards do not require an LED adapter, only factory original main lamp drivers require LED adapters.
Some Bally titles use additional boards to control more lamps, and require additional adapter set(s) to completely convert a game. 
Spectrum:  Requires 2 of this set
Space Invaders, Xenon, Flash Gordon, Eight Ball Deluxe (All versions), Fireball II, Embryon, Fathom, Medusa, Elektra, Vector, Speakeasy, Mr. and Mrs PacMan:    Require 1 of this set, and one the -52 AUX board sets.
 
Kiss,  Future Spa,  Centaur, Centaur II:  Require 1 of this set and one of the -42 AUX board sets
 
Does NOT work in Gold Ball,  Baby Pacman, Granny and the Gators, or Grand Slam.
 
Troubleshooting Addendum:
Some customers report issues where the adapters either don't work at all, or actually make the strobing problems  even worse.  This seems to be caused by one of two issues:
 
1:  Check continuity on the wiring harness. May have faulty crimps,  and potentially a bad spool of wire. 
2: Check the voltage on the spot you're attaching the alligator clip.   It should be around 5.5v to 6v,   if it's 3v-4v,  it's way too low and the adapters won't work there.   Check other lamp locations either in the backbox or even under the playfield.