I was recently given a Williams Contact that I'm working on getting back up and running. I've been ordering parts and need some coils, as 5 of them were completely burnt up. In going through things, I've noticed a a number of the coils in the machine don't exactly match those listed in the manual. Some differ by the letter prefix. Others are completely different. I assume some (probably all) of the differences are of no real concern, but would like to make sure. I don't really want to order coils I don't need at $10 a pop.

Side note - I've tried to read as much as I can on this before starting this thread. I understand some things. Using an SG-23 750 DC coil as an example. I know 23 represents the gauge of the wire used and that the 750 tells you how many turns the wire takes in the coil. DC is obviously for direct current. Mostly, I'm confused about the prefixes of the coils I have differing from the manual. I've read that it has to do with which way you should install the sleeve. I've also read that it has something to do with which side of the bobbin you should install a diode. I really have no idea.

The minor difference in prefix club.
Pop Bumpers
Two of the pop bumper coils were fried. The remaining coil is an SG-23 750-DC. The manual calls for G-23 750-DC on all three. I assume there's no real difference? PBR has both available. Any advantage to ordering 2 of one type over the other?

Ball return.
The coil in place is an SA-23 800-DC. Manual calls for A-23 800-DC. I assume I can just leave this as is.

Moving target coil
The coil in place is an M-36-5500. Manual calls for SM-36-5500. I assume I can just leave this as is.

Center post
The center post mech has two coils. One matches the manual.
The other coil in is a G-23 750-DC. Manual call for SG-23 750-DC. I assume I can just leave this as is.

The bigger differences:

Kicker/Slings
The game has two ball kickers down by the flippers. One is burnt out.
The remaining coil is an SG-23 750-DC. The manual calls for G-25 1000-DC. So, what I have differs in prefix and both gauge and turns. Any issue here? My limited understanding is that the 750 coil would be stronger than the 1000. Similar to above - PBR has both available. Any issues buying a 2nd SG-23 750-DC vs. buying a G-25 1000-DCs? Would the difference be noticeable?

Drop Targets.
Now this isn't even close. There are two coils in place. An SA-3-23 750-DC and a G-23 750-DC.
The manual calls for two SG-24 875-DC coils. I assume the coils in place are a bit stronger than needed. Any issues here?

Hmmm. As I typed the OP up, I realized something. If I wanted to just move coils around - I could have more things matching the manual. It's like someone played musical chairs here.

If I move the two G-23 750-DCs from the center post and drop target mechs to the pop bumpers, I could order 1 more of them and have all three match the manual. Then move the SG-23 750-DC currently on one of the pop bumpers to the center post mech.

If I really wanted to match the manual, these moves would leave me needing:
Two SG-24-875-DCs for the drop target assembly
Two G-25-1000-DCs for the right and left kickers.
One G-23-750-DC for the 3rd pop bumper.

With extra SG-23-750-DC and SA-3-23-750-DC coils on hand for the parts bin.

I don't really mind switching the coils around if there's any real benefit. Any opinions on this? Or should i just leave the drops assembly as is, order replacement coils to match the ones currently in place and call it a day?

Post #3 - I noticed that my little heart icon went gray again so I did something about it.

Thanks Lloyd. The more I thought about it and the more I let my OCD/Anal retentiveness think about it, I think I'm just going to move coils around as described in post 2 and order what I need in order to have things match the manual. Especially if the sling coil is overpowered - I don't need them launching the ball into plastics.

Give Prada a belly rub for me!