Checking coils...

vbtalent

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Is there a good way to test coils to determine if one is better than another assuming you had two of the same coils?

VB,
 
If they are the same, check the resistance. If it is too low then it is shorted somewhere. That's all I know of although I'm not sure what you mean by one being better than the other. If they are the same they should perform the same unless one is damaged.
 
if they are truly identical (not only in physical size, but in wire gauge, # of wraps, etc.) they should ohm out approximately the same - assuming both are fully functional. They don't "wear out" per se or get weaker over their life. Failure of a coil is almost always a mechanical issue - broken coil wire or overheating caused by some other mechanical failure.

Beyond that, a "better" coil is most always a function of better mechanics surrounding the coil - i.e. coil sleeve, plunger, links, etc.

If you just have two coils laying around and want to know which one to put in your machine...use your MM set to Ohms, one probe on each lead of the coil. The coils don't need to be attached to anything or be powered in any way. You should get a minimum of 3 ohms. Anything above = good coil, anything below you should replace.

Sorry if that's too simplistic and I didn't understand your question.
 
All other things being equal, which would be the more powerful coil? The one with the lower or higher resistance?

I was thinking lower, but then I thought, higher resistance will generate more heat right? And high power coils are the ones that tend to heat up more quickly?
 
All other things being equal, which would be the more powerful coil? The one with the lower or higher resistance?

Lower resistance. By lowering the resistance you increase the current through the coil, there by making the coil "more powerful". You can do this yourself by taking off the protective paper and removing some of the windings on the coil. This is explained very well here http://www.pinrepair.com/restore/index3.htm#perf
 
You guys are right on target.

I have 2 coils laying around and just wanted to know how to make a decision as to which one to use for the game. Since resistance is involved do I need to remove the diode or can I test them while it's still installed.

more resistance = better coil?

Thanks,
 
You can test the resistance with the diode installed. However, lower resistance and stronger coil does not necessarily mean better. My JP had too strong of flipper coils installed and it made the game much more difficult and hurt gameplay. I changed the coils out to the correct ones and it plays much better. You now have more ball control since it isn't slamming off the playfield items that are closer to the flippers. Flipper passes are easier. And the ball used to fly off the return habitrail because it went up the ramp so fast. Not to mention that it saves wear and tear on stuff.

The designers usually put a lot of thought into which coils they use so putting in stronger ones isn't always the best idea. That being said, sometimes the coils may be chosen for cost issues and the game could benefit from something stronger. My BF was a case of this, it needed a stronger right flipper coil to make the left ramp shot consistently.

Also keep in mind that lower resistance = stronger is a rule of thumb. There are other factors such as the wire gauge along with the number of turns that influence the strength. Granted, the gauge and number of turns (length of wire) directly influence the resistance and therefore the strength, but how the two factors are varied also has an influence.
 
You don't have to remove the diode. A typical diode will have a resistance reading of 100k+ ohms. Since your coil will be much lower, that's the reading you'll get. To make sure, because of the construction of the diode, when you take your coil reading, put the red lead of your meter on the banded side of the diode. That way the diode won't read at all.
Better is a gray area. Do you like stronger, faster, more powerful play (lower resistance) or do you like slower relaxed less powerful play (more resistance). Each manufacturer used different coils based on the build of the machine (more or less voltage in the coil circuit). The best thing you can do is compare your resistance readings of the same type of coil. If either of the two coils you have are close to the compared coil, then either will do. Just make sure the coil doesn't read a noticeable difference higher or lower than the compared coil. Anything less than 3ohms will be considered a short and that's not good (with the exception of the flipper coils).
 
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I should have mentioned the coils are direct replacements for the game. Im not trying to change what came original just looking for the better of the 2.

VB,
 
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I should have mentioned the coils are direct replacements for the game. Im not trying to change what came original just looooijg for the better of the 2.

VB,

Pick the one that looks better. Better yet, post a pic and let the group pick the best one.
 
You can test the resistance with the diode installed. However, lower resistance and stronger coil does not necessarily mean better. My JP had too strong of flipper coils installed and it made the game much more difficult and hurt gameplay. I changed the coils out to the correct ones and it plays much better. You now have more ball control since it isn't slamming off the playfield items that are closer to the flippers. Flipper passes are easier. And the ball used to fly off the return habitrail because it went up the ramp so fast. Not to mention that it saves wear and tear on stuff.

Definitely.... Stronger coils are good in some instances but take that away with the bad.... Drop targets take more of a beating, ramps and playfield plastics as well!
 
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