Isolating Transformer ... err .. why?

[Halo]

Hi there

Firstly, want to say what an awesome FAQ, I read it through and also found the 'How TV works' very enlightening!

I've got a few questions really. A lot of arcade cabs have an isolating transformer specifically for the monitor. Although I have looked at a lot of articles on the net .. I'm really looking for someone to give me an idiot proof, non-technical reason. Is it to specifically isolate mains power? If so .. if I intend to use an arcade monitor in a mame cab, must I also isolate it? And, finally .. what is the purpose of this isolation? Is it to protect me from being fried, my PC / Jamma boards from getting friend, or both?

I've got one more question, which kind of relates to this in a roundabout way. I'm planning to convert an old broken cocktail cabinet which I bought that was trashed. I'm in the process of gutting it ready for a PC / monitor .. and theres green earth wires EVERYWHERE!! They're connected to the coin mech, the locks, the service switch box, ther control panels .. there must be about 15 of them! Why so many? Why not just run three or four up through the bottom?

If you haven't guessed, yes .. I am a beginner

[tom61]

Is it to specifically isolate mains power? If so .. if I intend to use an arcade monitor in a mame cab, must I also isolate it? And, finally .. what is the purpose of this isolation? Is it to protect me from being fried, my PC / Jamma boards from getting friend, or both?

Yes, yes, both.

Probably all the grounding is for reduction of RF interference.

[delta88]

using an iso transformaer removes any ground signal/current(?) from the AC signal goin into the monitor chassis.

[Halo]

Thanks

[JasonF]

Actually, an isolation transformer as used in an arcade game is totally for protection (for both humans and electronics, particularly the monitor's).  Randy has got a great write-up about it:

http://slot-tech-ftp.serveftp.com:8080/general%20electronics/isolation%20transformers/isoxfmr.htm


Edit by moderator: fixed URL

[Halo]

Actually, an isolation transformer as used in an arcade game is totally for protection (for both humans and electronics, particularly the monitor's).  Randy has got a great write-up about it:

http://slot-tech-ftp.serveftp.com:8080/general%20electronics/isolation%20transformers/isoxfmr.htm


Edit by moderator: fixed URL

Hey .. that's great! Thanks very much for the link