Had a few of the single players over the years. Very bright & colorful play fields which last very well. Some nice themes and well designed games. Some weird ones as well. Some decent cabinet art, which was unusual on EM pins, Very popular over here in the UK, at the time. Basically the EM games are Williams inside, all the coils, steppers, score units, relays, score motor, most things are Williams. The first couple of games actually had Williams on the apron, changing to the triple Z apron a bit later. The three Z's were for the three Zaccaria brothers, who owned the company. The pops are the same design as late Gottlieb EM which will fit, though the art differs on the Z capped ones, others have designs that are close enough to allow Gottlieb ones to be substituted, unless it has to be totally original. Early games had a chime box which was the same design as a Gottlieb one. The electronic sound cards on later games, which also make the Biri Biri at 4 million, are very difficult to find. The one on Combat has an extra board to produce the explosions as the game is played. The later games also had an electronic card to make the pop bumpers and some other lighting flash, to give higher scores.There is a lot of info' on www.zaccariapinball.com, including many schematics, plastic scans and wiring diagrams for the sound card.
Some of the art was by Lorenzo Rimondini and he signed some back glasses, on the tail of Concorde on the Supersonic back glass, for example. It was common for two different back glasses to be used during production. I know there were two versions of Supersonic and Moon Shot, and probably others.
All in all, they're not at all bad games to own and play. As well built as US games, with better play field protection, better clear coat is the reason for that.

Just got these. They'll come up real nice with a bit of effort. Play fields are excellent, hardly a mark. Perfect inserts and key lines. Aerobatics back glass is perfect, Ski Jump needs a few touch ups, only minor. Cabinets are very nice. The Aerobatics is RAF Red Arrows themed, great for the UK. I wish they'd have put the bird on the Ski Jump p/f instead of the bloke. Bad choice in my opinion.
Aerobatics back glass.jpgAerobatics play field.jpgSki Jump back glass 005.jpgSki Jump play field.jpg

That Combat is in superb condition, as you say, MINT. Does it have the Biri Biri at 400,000?

Here's the green window bar version.
Moon Flight 0044 008.jpg

Mate,
You can get pop bumper caps from PBR. They're slightly domed instead of flat, the red lettering reads 1000 points when lit and is a bit darker but they fine and look great fitted.
http://www.pbresource.com/pfbumper.htm

What is the coil part number. It should be on the others, it'll be a Z with some numbers. It is a Williams coil really, so PBR will most probably have it. Just find the W coil with the same numbers and it will be identical.

Mate,
PBR list a Williams G22-550. I recently bought a chime box from a Lucky Fruit and that was a copy of a Gottlieb chime box, the chime coils Gottlieb used in a 1970 game are A12092. I reckon one or the other should work. Try mailing PBR with your coil dimensions to have them compare with the two and see if one is the same. Probably only the length of the coil matters, the plunger should be the same diameter, worth double checking. A standard chime/bell plunger should fit, I would think.