(Topic ID: 220013)

System 80B HELP! Switch Issues

By robx46

5 years ago


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  • 17 posts
  • 3 Pinsiders participating
  • Latest reply 5 years ago by robx46
  • Topic is favorited by 1 Pinsider

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#1 5 years ago

I'm officially stumped on this. I've worked on a number of 80b games before & they can be a bitch but I'm at a loss here. I've spent weeks on this before & now have to swallow my pride & ask for help.
Have a gottlieb genesis I'm restoring from the dead. I'm treating it right. New power supply, new driver board, new swemmer mpu, new roms, new crimp connectors (& yes of course the infamous harness, all new).

Switches aren't doing anything, I can't start a game, register a credit or even get into test mode. Game boots fine & sits there in attract mode. & I believe I've ruled out every possibility. It might only be the coin door area switches at J5 on the MPU, I don't know if it is the rest of the switch matrix because I can't start a game or go into test mode. Game still boots fine & sits there in attract mode.

I've cut an end & tested every single diode on the 1A7J1 diode strip board that is tied to these switches & confirmed that every connection is being made back to the boards. I even burned & installed new roms just because I was out of other ideas. & I have 2 different power supplies here that are both confirmed good. Board is definitely getting a solid uninterrupted 5v.
& I again confirmed that every dip switch matched the original game settings.
Lastly every ground modification is done & was just double checked. All but the MPU has the ground mod which I was told wasn't required on the new mpu & I am using the newly wired harness with all new connectors & extra the extra ground wires added.
I had already sent the board back to the k's arcade & he confirmed all switches working on his raven & that the mpu is good. I'm just at a loss at this point.

#2 5 years ago

Have you tried simulating the test switch closure with a jumper lead across switch strobe and switch return at the MPU board edge connector?

#3 5 years ago
Quoted from CactusJack:

Have you tried simulating the test switch closure with a jumper lead across switch strobe and switch return at the MPU board edge connector?

Yes it does work when I do that, I just don't know what I'm missing here.

#4 5 years ago

I don't mean to be insulting here (honestly!), but, did you repin the connectors for the switch matrix? If so, is there ANY chance the pins are on the wrong side of the board (Didn't use original housings)?

IF you know its not the above, then do the same jumper trick at the very first occurrence of the same two wire colors at the playfield. Preferably, before any diode strips.

#5 5 years ago

I wish it were that! It isn't & I've confirmed continuity from the wires to the board.
I've definitely tried jumping the switches, nothing happens. Might it have to be the diode strip then? It did test good. & I know my connections are all being made. There has to be something simple here, I know it. Switch matrix really doesn't have that many components to it & is pretty simple.

#6 5 years ago

It looks like you have a problem with return 7.
All the coin door switches goto return 7.
Only advance left and right go through return 6.

#7 5 years ago
Quoted from Inkochnito:

It looks like you have a problem with return 7.
All the coin door switches goto return 7.
Only advance left and right go through return 6.

That would make sense, the connections are 100% good though. I have continuity on return 7 wire starting at the diode strip board connector, all the way into the mpu itself where I have test points on the board. & also the connection from return wire 7 connector to the diode board is also confirmed good as it has continuity to all the ends of the diodes that are all part of return 7.

#8 5 years ago

Like I said, BEFORE the diode strip(s). You want to simulate exactly what you did at the connector (which you stated worked). So do the same thing down on the lower cabinet (for coin door) or playfield (for playfield switches). Then, you want to do the same for the other end of the switch. Or, at least the first occurrence of the wiring in the lower cabinet. Attached is a snipet of Black Hole's lower cab. switches.

We would need a photo of the switch matrix drawing(s) to give you more detail as I don't have a Genesis manual to look at.

bhcabsw (resized).JPGbhcabsw (resized).JPG

#9 5 years ago

I know the playfield switch harness probably plugs directly to the MPU board, but does the lower cabinet switch wiring go directly to the MPU edge connector or is there a molex connector in between to allow you to disconnect the head?

Continuity (Beep Test) is rarely a good thing when working on pinballs. If you are using the Beep as your indicator, some DMM will trigger the beep for anything lower than 200 or 300 ohms. Unless you are actually looking at the ohm value and comparing that value to what you get when your leads are touched together (like 1.2 ohms etc.) than you should not trust what your ears are hearing.

#10 5 years ago

Gotcha. So when I jump the wires without the diode board connected either via switch to return 7 on the diode board connector, or simply jumping the 2 right at the connector, they work. connections again confirmed good.
It has to be bad diodes doesn't it?

#11 5 years ago

Try adding your own diode in line with your jumper. You can try a 1N4148 or 4004 etc. The problem is, they have a higher voltage drop across them (than the original ones gottlieb used) which may be exactly what your issue is (too much loss before getting back to the ICs.)

#12 5 years ago

Here is a part of the Genesis manual in case you need it....
Put a jumper over A1J5 1&2 and you should be able to get into the test menu.

Genesis (resized).jpgGenesis (resized).jpg

#13 5 years ago

I did enter test mode earlier today through jumping on the board. Got into the switch test & it turns out none of my other switches are working either, at least not without jumping the returns to the switches themselves.
Could it be that all the diodes on all the diode boards are bad? I don't have any other explanations at this point. I'll find out tomorrow I ordered some new 1n270 diodes.

#14 5 years ago

What do you read in diode test across some of the diodes with you DMM? Did you try using an external diode?

Unless HV was put across the diodes, I find it hard to believe all the diodes are zapped.

What ICs is Schwermer using for 7404 and 7400 in Switch matrix?

3 weeks later
#15 5 years ago

Just an update on this & document it. So it did turn out that all the diodes on my diode board were shot. I just never would have guessed it. Man Gottlieb sucks hard to work on sometimes.
Now that I can start a game I have the mpu board seemingly freeze up on game start... so the fun isn't over yet!

#16 5 years ago

Is it a multiball game? If so, the start process won't continue until it sees a ball sitting on the max ball switch on the ball trough ramp. And, if a 4 ball game, a ball also on the outhole switch. Gottliebs will seem to go completely dead until they can account for all needed balls.

#17 5 years ago
Quoted from CactusJack:

Is it a multiball game? If so, the start process won't continue until it sees a ball sitting on the max ball switch on the ball trough ramp. And, if a 4 ball game, a ball also on the outhole switch. Gottliebs will seem to go completely dead until they can account for all needed balls.

Yep actually just a contact needed adjusted. On the home stretch.

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