What's new
Pinball info

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

System 80b - 12v issue ??? SOLVED

Sgt GrizZ

Sgt GrizZ

Registered
Joined
Jul 21, 2011
Messages
11,336
Location
Ex PinballInfo Admin . MIA Brighton Hove beach
Alias
Ive
Calling all Gott Sys 80b experts.

OK - my Night Moves A2 power supply board has been playing up. So I have another to put in.

Just double checking readings before plugging anything in and I have found that even with the game OFF and UNPLUGGED I am still reading 12V+ at the connector going into the small A2 power board

HUh ???? :hmm::hmm::hmm::hmm: What's going on - is this normal ? Concerned about proceeding any further.
 
Dodgy multi-meter, batteries dying maybe? I seem to remember a cap on the transformer board in the base, could that be holding some juice?
 
ronsplooter said:
Dodgy multi-meter, batteries dying maybe? I seem to remember a cap on the transformer board in the base, could that be holding some juice?
Click to expand...

You were right @ronsplooter .... capacitor ! Good call.

Just checked with Sir Squires, who knows this NM very well as it used to be in Swavesey ...as you know. Anyway yep he confirmed it. It came to light because with power off I was attaching it to the new board and got a nasty crackling noise as I did it. Which of course is always worrying :rofl:

Phew - so nothing to worry about. Until the next thing goes wrong - gotta love pinball machines !
 
OK - still got a problem.:(

The 12v (actually measure 14v) is present at connector.

As soon as connected to the A2 power board this drops to about 1.6v ??? This is the same whether the 5v connector from the board is connected or not.

This is happening on the original A2 board , and also on my new replacement board.

Any ideas ???

The ground at the 12v connector checks out fine all the way back to the transformer panel.
 
I'm thinking you have a disconnect on the earth somewhere. Has it had the earthing mods done? Before and after the earth connector that then feeds the side of the transformer.
 
Moonraker said:
I'm thinking you have a disconnect on the earth somewhere. Has it had the earthing mods done? Before and after the earth connector that then feeds the side of the transformer.
Click to expand...
I was wondering earth but it is good to all boards connected to the A2 power board.

And there is still the issue when the A2 is only connected to the 12v - with nothing else in the equation. Same with replacement board.

I don't think the earth mods have been done but this game has been rock solid since it's Swavesey days.

Sent from my D5833 using Tapatalk
 
I believe you have a difference in earths. Seen this before on a DE game, cap showing -12v or -18v when there was an earth disconnect. I think it was smoothing a BR and the answer was to tie the br earths direct rather than them going through a connector.
 
Quickly check connections at a12j6 as thats the 12v out from the bridge, pins4 and 5 are the live tho would be weird to have two pins bad. 're earth you can easily slave onto 1 or 2 on the power supply j1 connector or board directly. Also check cap at the 12v bridge
 
Last edited:
Poibug said:
Connector pins at connector fatigued? Quite common
Click to expand...

Redid connector. No change - as I suspected really.

Can someone explain to me why the 12v is dropping to 1.5v when the connector is attached to the board . It's fine ....as soon as attached the voltage drops. Happens with the old original board and the brand new replacement. I'm suspecting now that my original board isn't at fault and something else is amiss.

Not sure what to turn to next - beyond doing the whole ground mod palaver ...but I dont really want to do all that without knowing that *IS* the issue for sure.

Bleuuuugh. Hungover today so prob not the best time to be thinking about it :rolleyes:
 
Is it a ghost voltage, ie when under load it disappears so not actually 12v, rare but have had it happen.A test lamp good for that, if lamp doesn't light you have a problem at the connector near the bridge, or the actual bridge .slaving an earth as previously mentioned worth doing
 
Moonraker said:
. Has it had the earthing mods done? Before and after the earth connector that then feeds the side of the transformer.
Click to expand...

Interestingly ust following a discussion on Pinside and one of the guys on there says that it is not necessary to do the ground mods on the later System 80b games - as by that point Gottlieb were using trifurcon crimped connectors - much less likely to fail.

I'm gonna leave mine as it is. The old 'if it ain't broke ' rule :D
 
You must log in or register to reply here.
Back
Top Bottom