Spin bought his first pin

[SubaruBrat]

Scott,


Need help with 1979 System 1 Gottlieb "Count Down"



Got this and it does not boot.
Not sure if the MPU is working or not.
Removed the battery and scrubbed the board for the corrosion.


Looking for the next few things to check.
Pin powers up with lights (No score board lights)


Behind the Glass their is a light not light marked 6 volts test point it is not light.


This is my first pinball so would like some help.


Thanks
Virgil Spinelli AKA Spin

The background

Spin you picked an interesting one to start with. This game is a Solid State (SS) pin, and perhaps one of the more unusual ones. When we talk about SS we are referring to a game controlled by a simple computer Vs a system of relays and other devices to turn on lights and take action from switch inputs, those are referred to as Electro Mechanical (EM). In the mid 70's the existing pinball manufacturers were all transitioning to SS from EM. This reduced costs, made the game more reliable, and allowed for all sorts of things not possible, or not easily possible before; light patterns, digital sounds, dot matrix displays etc. Gottlieb, although experienced and talented in creating EM pins was lagging years behind the others in SS development. Since it was apparent that they didn't really understand the technology they built sort of a hybrid EM/SS game system that still used a great deal of EM methods and technology with a third party built computer that was primitive (4 bit) and had reliability issues. This impacts owners today since all those proprietary ICs are long since out of production and have become rare. The rest of the system is a decade behind the competition. When Bally was building digital speech cards Gottlieb was using three analog tone circuits.

So, why would anyone want to own such a poorly executed design? Because it has some really great games.

My favorites;

Close Encounters
Dragon
Charlie's Angles
Countdown
Hulk
Buck Rogers

The short story

The stock board set is a pain, it has diagnostics that the user can't see or control and many of the components are rare if you can find them. It was also poorly built and protected so failures are more frequent. It can be repaired if you can find the parts. The good news is there are so many popular games that there are several companies making replacement boards built using modern components that include real diagnostics and are repairable. So if you can't fix a board you can just replace it.

These guys sell a MPU and driver board

These guys sell a driver and power supply

These guys sell wireing harnesses

Before you do anything else, download and read this start to finish twice, pinrepair is your best friend.

The longer explaination

If you are inclined to replace the MPU because you think it is not booting rather than try and repair it you have to first find out if the current MPU has everything it needs to boot. The first thing you need to do is check the health of the power supply at each stage leading up to the MPU. The lights he described as coming on are likely the general illumination which is just that, a circuit of lights to light up the game. Pinrepair has a very specific procedure for checking out the power supply all the way to the MPU. If you get through that and have power then you need to start looking at repairing or replacing it (with some other checks first).

In the Pinrepair link above search for Testing the System1 Power Train.

More great info can be found under the section titled; Before Powering On: The Power Train and the Power Supply (Repair/Upgrade)

Other reasons it might not start include the SLAM switch, of which there are two, and the MPU won't start the game unless they are working or defeated. There is a simple one wire jumper to defeat it and I suggest doing that.


Once you check out that power supply let us know what you found. You might also want to start checking retailers like Marco Specialties, Lakeside Pinball and others to see who has the rubber set for your game, I would also add a new ball.

Other things to order are;

-100 #47 bulbs minimum (or enough to replace every bulb, these draw less power and the game runs cooler and breaks less because the components are less stressed.
-New leg levelers if needed
-Novus #1 and #2 cleaner and polish

Also look around for any broken targets, standoffs, etc. that you will need to order. If you keep the stock power supply you will want new capacitors. And once you get it working there are some basic mods descibed in pinrepair that you will want to do to make it more reliable.

[Spin]

So here is where I am at.

I have 2 displays out (Well displaying improperly)
Payer 3 & 4 displays work
The Match display inop.

2 of the 4 drop targets will not reset.
I have new solenoids so it is not that.

Other than that the pin is working OK.
Any help appreciated.
Thanks
Spin

[Leathco]

You got great help in SuburuBrat. Congrats on the pinball machine, I'm hoping to pick one up if I can find one at the right price.

[RetroPom]

Never heard of it before - So had a look on IPDB:
http://www.ipdb.org/search.pl?any=co...type=quick#573
Looks interesting - Doubt I will get a chance in RL,LUCKY YOU , so pleased to see a VP versiob available
http://www.pinballnirvana.com/modules.php

Will have to give it a bash

[Spin]

My back 2 drop targets are driving me crazy.
Just can not figure why both are out.
I had 1 out now they both are out.
Ugg

[Spin]

OK back in the machine.
I now have 3 of the 4 targets working.
Back green targets still not working.

Also my Top displays and the lower match/ credit display out.
I have swapped the top displays so they are good. They display a 1 occasionally.
More to follow

[SubaruBrat]

Spin, I PM'd you back, what steps of the test procedure were failing or giving you trouble? If you swapped the displays and the top ones worked in the lower locations you are looking at the high voltage (not as high as compared to other brands) that runs the displays or the decoders. The first check is to make sure you have 60v present at the top displays and credit/match display, it probably will be fine. If you do barring some bizarre wiring problem your likely bandit will be the display driver.

This is a fork in the road, the displays are driven by one of those rare and difficult to replace spider ICs that make up the 4 bit controller board, and some 7448 ICs that are about $5 each and not as hard to find. If you replace those and they displays work then cool, if the 7448s are good and the spider IC is bad your likely better off buying a new controller board. You could always swap the 7448 controlling the a top display (Z16) with the one controlling the lowers (Z17) and see if your problem swaps places. If they are socketed on your board this gets real easy, otherwise just order a new 7448 and replace the 7448 at Z16. Since the 7448 at Z16 controls the top displays and credit/match segment it is a strong possibility that it is your problem. You might just be a $5 IC away from having your displays all working.

(I just checked on Ebay, there are three sellers right now that have the 7448s.

[Spin]

Got the message.
Thought that I would return posting here to let others feel and live the pain and enjoyment of fixing a pinball.
I am off to test further.
More to follow.
BTW Thanks for the help
Spin

[Spin]

Made progress tonight.
Got the targets working.
Replaced both of the transistors under the playfield.
Got a replacement chip in the 7448, My top 2 displays are now working.
The Credit/ ball (lower display) has garbled characters still.

And I still have never seen the Tilt and Shoot again lights light?

Making progress. Thanks

[Spin]

Stuck on where the weird display problem is.
garbled characters in the match/credit display.
Lights up but characters are weird.

Haven't found the missing 6 volts that should be in the back board test point.