Aero City grounding question

[dos]

I'm working on an Aero City that had absolutely no grounding, just a single disconnected ground harness laying at the bottom with broken ring terminals. Very sad. I set about redoing the internal grounding based on the info I can find about what connects to the main ground lug and came up with this:

I know that the single cable with white connector goes to the control panel, with another connector at the other end going to a short cable with a ring terminal that attaches to the LS-32 mounting plate screw. I'm actually not sure if it had a connector at the earth stud end or if it was directly connected via ring terminal (entire control panel grounds were missing), but I added one to make removal of the entire power panel easier. So as far as that goes, we're good. My question is regarding the cables coming from the brown connector, this is the harness that was at the floor of my cab. Two cables come off it, both ending in ring terminals. Where were these ring terminals originally attached, and did those branch off to other places via additional ring terminated cables? I can make some educated guesses (monitor frame, coin mech) but I want to know how the cab was originally wired, if possible. Am I missing anything else to connect to the earth ground stud on the power panel? My Astro seems to have a lot more grounding going on and I'm wondering if I am missing more original cables.

 

[kikaso]

My guess would be the PSU and the noise filter. I don’t think the monitor frame is grounded on Sega cabinets.

 

[dos]

Thing is, I've looked at tons of pictures of Aero internals, even untouched looking cabs and neither of those ever seem to be grounded. Granted, I don't see grounded monitor frames or coin mechs either. Those wires coming off the brown connector are always going off to some unphotographed place

 

[nem]

Technically, as it's an all metal cab, you can get away with very few actual ground wires.

The PSUs on the Aeros that I have aren't grounded. I haven't checked if Earth ground is tied to DC ground on the PSU. If they're connected I wouldn't ground the PSU, but if they're not, there's no harm in grounding it.

And yeah, don't ground the monitor frame. Doing that can cause visible interference.

 

[dos]

Yeah I've removed monitor frame grounds from cabs that came with it for that reason. Always assumed it was just a problem with my house wiring as most grounded metal appliances I connect become slightly hot.

At least on my cab, the PSU is totally isolated from earth ground. I normally tie earth and DC if there is interference, but I've haven't had to do this with Sega PSUs.

Still wondering where there ring terminals coming off the brown connector were originally meant to go.

 

[Hackcell]

Technically, as it's an all metal cab, you can get away with very few actual ground wires.

The PSUs on the Aeros that I have aren't grounded. I haven't checked if Earth ground is tied to DC ground on the PSU. If they're connected I wouldn't ground the PSU, but if they're not, there's no harm in grounding it.

And yeah, don't ground the monitor frame. Doing that can cause visible interference.

About this grounding the monitor frame, is it true in all monitors? I have 2 metalic cabs with the monitor frame grounded and sometimes I get some interference.

Thanks!

 

[dos]

About this grounding the monitor frame, is it true in all monitors? I have 2 metalic cabs with the monitor frame grounded and sometimes I get some interference.

Thanks!

Yeah, I have found that removing the ground from the monitor frame will clear up a particular kind of interference that looks like wavy scrolling lines. Note that if you're seeing something that looks like weird colored parts of the screen that isn't really interference, just magnetism which can be fixed by degaussing. In some cabs that use the generic PSUs with screw terminals, trying the earth ground to DC ground can also remove interference.

 

[Hackcell]

Yeah, I have found that removing the ground from the monitor frame will clear up a particular kind of interference that looks like wavy scrolling lines. Note that if you're seeing something that looks like weird colored parts of the screen that isn't really interference, just magnetism which can be fixed by degaussing. In some cabs that use the generic PSUs with screw terminals, trying the earth ground to DC ground can also remove interference.

Thanks! One of the cabinets is a sega swing. The chassis (ms8-26) does not include a 3rd/grounding prong, but the cabinet didn’t come with an isolation transformer. Do I need to install one?

 

[dos]

Thanks! One of the cabinets is a sega swing. The chassis (ms8-26) does not include a 3rd/grounding prong, but the cabinet didn’t come with an isolation transformer. Do I need to install one?

I don't think any chassis has a grounding prong on the power cord. I know most Nanaos have isolated power sections built in so don't need an iso.

 

[nem]

I just checked the two kinds of PSUs I have in my Aeros and neither have Earth ground tied to DC ground, so if you want to add an extra ground wire to that, go ahead!

 

[dos]

I just checked the two kinds of PSUs I have in my Aeros and neither have Earth ground tied to DC ground, so if you want to add an extra ground wire to that, go ahead!

I may do this if there is interference, not sure yet, but thanks for the info.

Do you know where the two cables coming off the brown connector in my photo go to on your cabs?

 

[nem]

Do you know where the two cables coming off the brown connector in my photo go to on your cabs?

One goes to the L-shaped bracket that has the edge connector for the jamma harness at the front of the cab. The other one goes to the control panel.

I can't see grounding the PSU affecting interference. If you regularly have your hands on the PSU when the cab is running and don't enjoy possibly getting a mild shock from it, you would want to ground it. Otherwise I wouldn't bother.

 

[dos]

One goes to the L-shaped bracket that has the edge connector for the jamma harness at the front of the cab. The other one goes to the control panel.

I can't see grounding the PSU affecting interference. If you regularly have you hands on the PSU when the cab is running and don't enjoy possibly getting a mild shock from it, you would want to ground it. Otherwise I wouldn't bother.

Thanks for the info re the brown connector. Yeah grounding the PSU was a hypothetical and I was more talking about tying the ground to DC negative, which is a well known fix for interference when using the generic screw terminal PSUs. I have never had to do this with a Sega PSU though and don't really expect to here.