MCR Filter Assembly ... Identifying Cap Terminals

kentmurphy

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Folks I need some help. I am trying to replace the two filter caps in the filter assembly in my Kick, but I can't identify the positive and negative terminals on the old caps. Each cap has a red dot painted one terminal. Would this happen to be the positive terminal?

Below is a pic of the same filter chassis / assembly which is in my Kick. This is not a pic of mine.

http://home.comcast.net/~dark.paladin/tron/images/tiger10.jpg

Thanks
 
If the caps are filtering AC voltage then either follow the circuit from the AC input to the cap (the positive will be facing the input), or test for continuity with a multimeter from the AC input to the caps terminals. You won't get a reading on the negative terminal because the cap will block the DC from the multimeter.

If they are filtering DC then do the same thing but from one of the rectifier diodes.
 
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Thanks guys and thanks for the link tng25.

Since I assumed the positive terminals were marked with a red dot, I completed my rebuild last night and the hum bars are now almost completely gone. There is a faint hint of bars, but they are barely noticeable. I replaced the fuse block, all fuses, the line filter, and the 2 large filter capacitors. I had no idea there were 4 diodes on top of the filter assembly and the metal can laying on its side was an oil filled capacitor.

How the heck were you able to find a source for the oil capacitor????

Thanks again.

Yes, the red painted terminal is the positive one. I rebuilt my Tron PS recently. Here's a link to the write up. Hopefully something there will help.

https://sites.google.com/site/3vmearcade/Home/tron/tron-mcr-suitcase-rebuild
 
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common to you, but uncommon to me ... why would an arcade game need a motor start capacitor??? .. :)
 
No idea why it needs it. I found the source from digging through KLOV threads! Probably didn't need a new one, but I tend to 'shotgun' my repairs so I don't have to worry about it in the future.

-Torin
 
No idea why it needs it. I found the source from digging through KLOV threads! Probably didn't need a new one, but I tend to 'shotgun' my repairs so I don't have to worry about it in the future.

-Torin

A few times.....I have seen the oil cap cause a hum bar. It can (and does) go bad.

Edward
 
why would an arcade game need a motor start capacitor??? .. :)
Sometimes people refer to any large capacitor a "motor start" capacitor, but there are three capacitors used on that transformer assembly:

- The 55kuF (12v supply) / 100kuF (5v supply) are typical smoothing capacitors. These are expensive so replace them if you are using the original linear power supply and you've measured enough AC ripple to justify the cost.

- The 3.5kuF is the constant-voltage transformer's tank circuit (see explanation). As it says, this is a cheap way to handle incoming voltage fluctuations. It's uncommon that you'd need or want to mess with this one.
 
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