US cabs, electroplating, and earth connections...

[biggestsonicfan]

Greetings all...

So when I began my journey after picking up an extensively worn Virtua Fighter 1 cabinet, I went in blind. I simply thought I could Evapo-rust and Naval Jelly the big rust spots off certain things and then sand it down to a nice metallic finish.







Little did I understand that there was a protective coating on the metal to keep it for rusting even worse, and rust it did again. So I gave it another sand then coated it in spray paint primer.

Well, part of what I saw before I dismantled my cabinet and failed to realize, is that all this metal is both electroplated and connected to the earth wire. Obviously what I have done has seriously affected that.

I would like to know the purpose of everything being connected to common ground, where cabinets in other countries don't seem to have this. And if it's necessary for the safety of operation, is there anything I can do at this point to salvage what I've done, such as citristriping the primers off and sending the metals to get professionally re-electroplated?

 

[Zepherino]

Others can chime in to correct me, but my guess is that all metal parts of the cab are grounded so that if something goes seriously wrong with the PSU/wiring, the cab itself doesn't become live and turn into a shock risk. Some styles of cabs have less grounding because they aren't made of metal, and are made of plastic/resin/fiberglass or wood instead. Even then, stuff like metal control panels are probably still grounded.

 

[tiff_lee]

For the purpose of earth/continuity bonding you just need a good connection between the metal surfaces. You will probably find the metallic fixings that screw into each panel is going to provide a good enough connection for zero potential difference as it interfaces with the threads but without testing with a meter you can't be sure, if in doubt you can sand back and expose some clean metal under the fixing heads to ensure good contact.

As above the earthing/bonding arrangement is to stop any potential difference between panels, so if one was to become live they all become live and with the cabinet being grounded your circuit fault protection circuit should trip on earth leakage current preventing electrocution. If you have a live ungrounded metal panel and you touch it, you then become the path to ground for that fault current but again circuit fault protection should trip at no more than 30mA to protect you.

 

[dos]

From my experience, the plastic cabs have more grounding wires going to basically everything metal you can touch. Metal cabs like Aeros don't seem to have much internal ground wiring, I guess the original finish on them is conductive enough to suitably ground everything attached to it (and it is tied to ground via the back power panel). The CP definitely has its own ground wire though. I actually posted a thread wondering what else on an Aero needs/originally had dedicated ground wires (as my cab had none) and the consensus seemd to be "not much".

 

[biggestsonicfan]

You will probably find the metallic fixings that screw into each panel is going to provide a good enough connection for zero potential difference as it interfaces with the threads but without testing with a meter you can't be sure, if in doubt you can sand back and expose some clean metal under the fixing heads to ensure good contact.

Oh wow I actually had not considered that at all! Makes perfect sense to me!

Others can chime in to correct me, but my guess is that all metal parts of the cab are grounded so that if something goes seriously wrong with the PSU/wiring, the cab itself doesn't become live and turn into a shock risk.

Ah yeah I figured that but I just didn't know if say covering a metal part in paint that was previously grounded would increase risk or not. Granted the top originally had a vinyl decal I think it should be fine mostly for the player controls. As for the service controls, I don't know if all those buttons use a shielded ground but I will indeed check (the degauss switch is welded to the panel lol).