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Coil hum.

JMP

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Joined
Aug 12, 2011
Messages
3,466
Location
Lancashire
Got a diverter rod coil mechanism humming when energised. Have taken it apart and re-assembled with no difference, all screws tight etc. Nothing loose except for some play between the armature and coil sleeve but that appears normal..... Any suggestions? Is a coil replacement worthwhile?



Have read some web references on this where 'coil stops' are mentioned. What part of the mechanism is this? Thanks for any help.
 
JMP' date=' post: 1690117 said:
Got a diverter rod coil mechanism humming when energised. Have taken it apart and re-assembled with no difference, all screws tight etc. Nothing loose except for some play between the armature and coil sleeve but that appears normal..... Any suggestions? Is a coil replacement worthwhile?



Have read some web references on this where 'coil stops' are mentioned. What part of the mechanism is this? Thanks for any help.



Coil stop is the bit at the rear end ...as it were ....that holds the coil in place. Sometimes called Coil Stop Bracket. See diagram : )



http://www.pinballmania.co.uk/flipkit.htm
 
Thanks. Any ideas on the hum? Read somewhere it could lead to a melting coil....? Not sure if to believe that.
 
The coil hums because it is being pulsed on and off during hold (so that it doesn't overheat). There's really not alot to worry about. If the humming annoys you, it may be possible to reduce it by replacing the plunger and or end stop. Or it may not help at all.
 
Oh right, thanks. It's not that bad, I was just bothered it may get worse or should be replaced. Thanks for confirming Andy.
 
Is there an LM339 involved anywhere in the circuit ?

Does an opto open the gate ?



I ask because LM339's can flicker an output on and off really quickly. I had to replace one once on a Fliptronic board because a flipper was humming.
 
Rfm and Congo which I have owned both had diverters and ball stoppers (for want of a better word!!) and they hum when energised. I wouldn't worry. If Andy isn't worried, I ain't worried!!!! ;-)
 
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