Sys80 Ground Mods or not?

vipe155

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So, I just picked up a System80. I've known about the work they might need, etc. for awhile because I've read the repair guides knowing I wanted to have a Gottlieb one day.

The game has a Ni-Wumpf CPU board in it. Besides that, everything else seems to be stock, but one of the guys at the place I bought it from said doing the ground mods would be fine, but not necessarily needed. He pretty much said that if the game isn't going to be on all day (it's not), you don't need to worry about it. So, does that advice sound ok, or should I fix that stuff anyway?

Also, I need a 10 ohm, 5 watt resistor for a replacement spinner motor. I'm having trouble finding one; Can I use a 10 ohm, 10 watt or something like that and get similiar results?
 
So, I just picked up a System80. I've known about the work they might need, etc. for awhile because I've read the repair guides knowing I wanted to have a Gottlieb one day.

The game has a Ni-Wumpf CPU board in it. Besides that, everything else seems to be stock, but one of the guys at the place I bought it from said doing the ground mods would be fine, but not necessarily needed. He pretty much said that if the game isn't going to be on all day (it's not), you don't need to worry about it. So, does that advice sound ok, or should I fix that stuff anyway?

Also, I need a 10 ohm, 5 watt resistor for a replacement spinner motor. I'm having trouble finding one; Can I use a 10 ohm, 10 watt or something like that and get similiar results?

You can always go up in watts/volts but not in ohms so yes you would be fine. Most of the time the watt/voltage rates typically never max at the original value so more is OK. Seems most of the time the larger the wattage the larger the component size FYI.

As far as grounding mods - absolutely.
 
you can always go up in watts/volts but not in ohms so yes you would be fine. Most of the time the watt/voltage rates typically never max at the original value so more is ok. Seems most of the time the larger the wattage the larger the component size fyi.

As far as grounding mods - absolutely.

+10000000000
 
I would say it's a must...IF it's Haunted House, Black Hole or any of this era of pins, it's a definite necessity!

It's kinda a weird. My buddy has a Premier Victory, and that thing hasn't had any mods done, and still running like a champ... At the same time, I have a Gottlieb Genesis (almost same era), and that would act all crazy til I did the mods!!!!

I heard you don't really need on System 3 machines.... Can someone clarify that?
 
If you want a bunch of coils to lock on and noxious smoke to pour out of the machine one day when you're having a party and decided to leave the game on unattended then sure... don't do the ground mods. You'll save like $2!

A game might run fine for years with no ground mods. Then again it might not and it just might cause you all kinds of pain in the process. Why even risk it with something so cheap, easy and recommended as a necessity by pretty much everyone who's ever heard the words System 80.
 
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If you want a bunch of coils to lock on and noxious smoke to pour out of the machine one day when you're having a party and decided to leave the game on unattended then sure... don't do the ground mods. You'll save like $2!

A game might run fine for years with no ground mods. Then again it might not and it just might cause you all kinds of pain in the process. Why even risk it with something so cheap, easy and recommended as a necessity by pretty much everyone who's ever heard the words System 80.

I get the point.... I was just asking since I'm only used to Williams/Bally games, and the Gottlieb stuff is actually fairly different. Also, I just wanted to see what the reaction was to the opinion the guy at the shop gave me.

Does anybody sell a ground mod parts kit? Reading through the pages of pinrepair.com, it seems like you have to search through it to figure out what parts are required.
 
Pretty much the point of this mod is to eliminate molex connectors because the molex connectors will loose connectivity due to the male pins getting "crusty" for lack of better term. When this happens it'll cause strain else where and/or flakiness. You're simply eliminating molex connectors and securing the ground wires down with crimp connectors. You're ensuring a solid ground is consistently made and maintained.
 
That's a big help. So, is there not many parts besides wire? I guess I thought it required a bunch of board work/transistors/diodes/traces/etc.

Nope. Just wire. You're just ensuring that there is a good connection between each board and a common ground.

The original connectors become tarnished or lose tension. Worst case scenario is some driver transistors become biased as a result and some coils lock on.
 
Nope. Just wire. You're just ensuring that there is a good connection between each board and a common ground.

The original connectors become tarnished or lose tension. Worst case scenario is some driver transistors become biased as a result and some coils lock on.

I've got all the backbox ground mods done except for the Ni-Wumpf CPU/MPU board. Anyone know where (or have a picture of where) to run the wire for that?
 
the ground !!!!!
on the board
the ground rail
negative side of a capacitor
grounded through hole mount

:)

Umm, the Ni-Wumpf is a little different. There are no large capacitors with + and -, nor do I have a schematic or the knowledge of where the ground rail is.
 
Ok, ALL the backbox mods are done. The only thing is the power supply in the lower cabinet. I've looked at example pictures on pinrepair, etc. and none of them show what looks like this games setup. Here are a couple of pictures:

IMG_1330.jpg

IMG_1331.jpg


I assume that the ground goes through those connectors. So what can I do to modify this and ensure the connectors don't cause issues later? Also, I am replacing that Orange Cap as soon as the replacement gets here.
 
pinrepair.com has a section showing how to deal with that......basically you solder all the ground wires together just before/after the connector plug. By doing that you are tying all the ground wires to every available pin on the connector. In the event one of your pins or connectors takes a crap, there are numerous other paths for ground to travel.
 
pinrepair.com has a section showing how to deal with that......basically you solder all the ground wires together just before/after the connector plug. By doing that you are tying all the ground wires to every available pin on the connector. In the event one of your pins or connectors takes a crap, there are numerous other paths for ground to travel.

I saw something like that, but what do you really do there? Strip a small section off of each wire, then wrap bare wire around all of them, then solder?

Even then, the connector still is a weak point. I wonder why they didn't just solder direct to the copper strip without any kind of connector at all?
 
I saw something like that, but what do you really do there? Strip a small section off of each wire, then wrap bare wire around all of them, then solder?

Even then, the connector still is a weak point. I wonder why they didn't just solder direct to the copper strip without any kind of connector at all?

The connector is the weak point -- but if you tie all the wires together than you have several of the contacts running in parallel. Before, if you lost just one contact, you would be hosed. Now you could lose more than one and still be grounded.

Agreed that a direct connect to the ground strip would be best connection. But in doing this, you make it more difficult to remove the cabinet transformer board in one piece or other assemblies. Probably wouldn't matter because most of us never plan on removing these anyways.

Ed
 
I saw something like that, but what do you really do there? Strip a small section off of each wire, then wrap bare wire around all of them, then solder?

IF I was gonna do this, I'd probably just cut the wires 4-5" from where they enter the plug....strip both ends of the wires...then tie them all back together, soldering them together as I went. Per the photo at pinrepair, it's not a very attractive proposition, so I'd probably have some large heat shrink wrap around to finish things off nicely.
 
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