You can make your own...see my avatar

And before anyone asks

Yes, it does work.

No, I didn't make it.

BH Reset Board Hack.JPG

_{Post edited by woz: Added pic}

IIRC the reset board monitors the digit strobes. If the CPU gets locked up and the digits stop strobing then the CPU is reset. The purpose is to prevent locked on coils and lamps due to a locked up CPU.

Small resistor on the plug into TC1 -- pullup resistor of 3.3K to the Read/Write signal. Some MPU boards run fine without it, some will kind-of work without it, and some refuse to work at all without it.
So... if you leave the connector on the TC1 40-pin DIP and unplug the 7-pin connector from the reset board - does they work then?
If it does work, you need to add a 3.3K resistor to bottom of TC1 between pins 7 and 11 and then leave the plug off of TC1.

If you want it to run without the board you have to unplug it from the socket on the MPU board. If you leave that plugged in then just unplug the connector from the reset board the machine will not boot.

As others have mentioned the board is to keep something from burning up should the MPU lock up. Not such a big deal in your home where someone is likely at the game while it is on, but for a machine on location if it locked up somone may not be there or not notice that a coil was locked on and could burn the coil and or transistor up.

If you have one without the reset board be sure you don't leave it unattended while on. I have 4 80a/b machines and the only one without the reset board hooked up is the one with a new aftermarket MPU board in it that doesn't have a socket on the board for the reset. That being said I have never noticed any of them locking up.

I laugh every time I see that reset board hack, it's my favorite.

Steve

The reset boards are a really good idea; most of the other pinball systems had a watchdog circuit but System 80 doesn't.

Unfortunately, after 25 years, the caps are dried out and the boards' timing is off, so they don't work right. I re-capped mine and had good luck with it, but I have since sold them so I can't give a status report.

Other way around. If you leave the plug installed on the TC1 connector and pull the 7 pin plug -- the game should still boot. In fact, some games would not boot at all or ran intermittently without the DIP plug installed on TC1. This was due to an overloaded Read/Write line (another poor board design). The DIP plug had a pullup resistor installed that would add extra pullup current to the Read/Write line.

But as the last poster said -- if you leave it completely hooked up and you have problems, there is a good chance that the old electrolytic caps are dried out. As caps dry out, they decline in capacitance value - resulting in shorter and shorter watchdog periods.

Try the 3.3K pullup resistor on the boards that insist on having the reset boards installed. I have seen this resistor fix this exact problem.

This is totally opposite of my experience, I just double checked it on my Genesis and it will not boot with the connector unplugged from the reset board but if you unplug the larger connector from its socket on the MPU board it will boot fine.

That's not right...the only thing connected on Genesis is the IRQ (twice), reset and power. Disconnecting from the module at the 7-pin plug should do nothing other than reflections on a very slow O/C IRQ. If you have a fading RIOT on the edge - I can see how the IRQ antenna might have an affect...but have never seen or heard of this happening.

I've seen several boards that did not run or run right until the 3K resistor mod is done -- which is on that 40 pin DIP. You can see it towards the middle of your manual's page 23. This fixes an overloaded Read/Write line. The 3K adds quite abit of pullup and fixes lots of problematic boards. To test this theory, we install the 40 pin DIP plug -- if it fixes things then the 3K is what's needed. The original poster's comments describe the exact problem we see when it needs the 3K pullup.

No issues with the genesis, boots and plays fine, never had any issues with it other than cold solder joints when I first got it.

The lovely world of Gottlieb sy80's

I removed the reset board on my Super Orbit and it still worked fine. Those are made to stop a coil fire or if the CPU locks up when on location.

I just replaced most of the boards with a Pascal PI-80x board....freakin awesome. Recommend it.

I've seen several reset boards now where the electrolytic capacitors on them have failed causing reset issues (no boot or intermittently resetting in the middle of a game). I confirmed bad caps with my CapAnalyzer 88A capacitor ESR meter.

Note: be careful unsoldering the electrolytics from the reset board. The traces are very delicate and will lift off very easily, even with a Hakko 808.

If you're always in front of your game when it's powered on, the reset board isn't a huge deal.

If you have a party and your friends are not all pinball collectors familiar with what a locked coil looks like, the reset board (with new caps) is extra insurance for when you go to get a drink and the game gets all crashy.

I gotcha. All gone now. PI-80X to the rescue! LOL....I only had it off for about a week before the board came. Wondered what would happen.

I have a non working jacks to open and the reset board is there with a missing harness. I don’t see or feel a resistor installed (on back side) on the tc1.

How do I correctly get the game to boot without the harness? Resistor between pin 7 and 11?

Otherwise if it is needed I’ll let my neighbor know and will need a source for the harness.

image (resized).jpg

https://www.pinwiki.com/wiki/index.php?title=Gottlieb_System_80#Reset_Board

I don't think that would be the cause of the booting issue, though.

The game will boot without the reset board. Problem is the MPU is probably wonky as old as it is. If you get it up and running without the reset board, you need to be careful that no coils are locked on or they will smoke and take out parts on the driver board too. Have you tried to boot the game? Does anything work? Have you checked all the coils to make sure none look burned or read less than a couple of ohms? Check/inspect/reseat all the cables in the backbox especially the big one from the MPU to the driver board?

I am really good at soldering and fixing boards, but at this point I don't even mess around with these 40+ year old boards. If they don't work, I yank them out and put in a Pascal or Ni-Wumpf. To me even if its an easy fix, the next problem is right around the corner when I have guest over or the machine is being used in a tournament. I would rather just fix the game so it works until I am pushing up daisies.

This is in reference to the Read/Write pullup resistor that Gottlieb added to the 40 pin DIP adapter. Games will work without the reset board but some boards do refuse to work without the Read/Write pullup resistor.

The 3K resistor is there for two reasons:
1 -- it provides a stable Read/Write signal at board power-up. There is a tiny fraction of time at power up where data can be written into Z5 but due to gate Z36A, this data write is prevented. The resistor does provide a proper biasing to the Read/Write line at time of powerup.
2 -- more importantly - A rockwell 6502 has a minimum VOH of 2.4volts, a 4069 requires a minimum VIH of 4 volts.
In other words:
The Read/Write output from U1 (pin 34) guarantees the output will be 2.4 volts or higher for a logic 1.
The 4069 located at Z36D (pin 9 input of Z36) requires the input to be 4 volts or higher for a logic 1.
The 3K pullup resistor pulls the Z36D input closer to the required voltage range.

This is fixed with a 3K resistor between pins 7 and 11 on the bottom of TC1 on the CPU board and you can see the photo of this mod on the link provided by ForceFlow.
Do realize that even though this problem exists on all System 80/80A/80B boards but only a very small fraction of these Gottlieb boards exhibit any symptoms. The chances that you have one if these that exhibit symptoms is quite slim.

LOTS of things can cause the board to not boot. Starting with the easiest:
Do you have good 5V power to the board with solid power and ground connections?
Is there any battery corrosion on the board?
Is the shared Interrupt Request line (IRQ) being held low by a bad RIOT?

Oh man, if it was my game, pascal all in one and be done. But it seams my neighbors and friends aren't as free with their repair/money as I am...but I hate troubleshooting with "maybe" working boards....

Yeah, i'm working on validating each power line off the transformers now. so once I verify those I can check for the booting.

What/where is the IRQ and RIOT? have not dove into that yet. Since thee displays don't show, I figured I need to get all the power lines verified and it seams the caps for the rectifiers are shot, so that is my start tonight.

You can end the misery by sending that board to me for repair.
—
Chris Hibler - CARGPB #31
Http://chrishiblerpinball.com/contact
http://www.PinWiki.com/ - The new place for pinball repair info

G-P-E Ed...I copied the info you provided above to the PinWiki section. Thanks for the beefier explanation!
--
Chris Hibler - CARGPB #31
http://www.ChrisHiblerPinball.com/Contact ... for board repairs
http://www.PinWiki.com - The Place to go for Pinball Repair Info