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Atari Pinball repair.

DanLewell

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Joined
Jul 21, 2011
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1,041
Location
Northampton, UK
Anyone on here got any experience with fixing up Atari Pinballs?

I've got an old middle earth that has sat underneath my other machines all neglected. I want to get it up and running but know there is a problem with the board that I will try to troubleshoot but will almost certainly be out of my depth straight away.

I'll post a video of it later if I get some legs on it tonight.
 
I had a space riders many years ago, I never got it fully working due to lack of knowledge! But I think the electronics are fairly simple to be honest, look forward to the thread

Ronnie
 
Middle Earth - interesting, that def needs resurrecting. Last time I saw one was at Pins Anon HQ 10 years ago, where it always seemed to be under repair.

Everything is fixable ! Remember ..... 'where theres a whip, theres a way' :D

 
We fixed one of those about 9 years ago....a guy in Yorkshire...who I cannot remember at all bought it..the playfield was mint..he paid £380 for it.....think diy fix is the way forward unless you are going to keep it. As I seem to recal it took us ages to get a circuit diagram etc. For it. But there maybe one on ipdb these days.......it was like playing pinball in slow motion..I will see if I have any pics of it...:thumbs:
 
I'm sure there was documents when I had mine? even guys who were helping me get it working, lots of obsolete chips on the board. Mine worked but half the switches never registered. It was a space riders backglass was loverly. I bought it for £35 it was fully working, I was soldering a wire back on a coil (while powered) a blob of solder dropped onto the board! never worked right after that. sold it some years later for £100 ish on Ebay
 
I think I still have a Space Riders manual somewhere should anyone need one...
 
right, Its powered up and doing exactly what I remember it doing which is all of the coils (except flippers) going crazy, lights flashing and the score displays flashing up random crap shown in this video.

Apparently this is what happens when there's a reset issue with the CPU.

Reading online someone said the first thing to check is the voltages, to make sure the board is getting what it expects. So DMM at the ready, but there are no test points on the board to check the voltages so I've look at the schematic (http://mirror2.ipdb.org/files/1590/...l_page_28_blank_with_paginated_schematics.pdf Page 35 and 36) and it looks like I should be getting the logic power and logic Ground going to J10 of the main board.

Physically this is obvious as it comes straight from the power supply to the board. So I unplugged from the board to measure the voltage across the two pins that the voltage should be coming in on. But getting nothing. :(

connected it back up and turned it back on, expecting it to go crazy again but getting no life at all now. :(:(

So, I'm guessing there is a problem with the power somewhere. I can sort of work out whats going on with the power coming in, but only sort of, and I don't want to kill myself, so I thought I should check before I go poking around in anything I don't get yet.

20170515_211559_resized.jpg
The White cable going to the step down transformer at the front is mains from the socket. Getting 240V on that and getting 118V on the output of that transformer that goes to the transformer board at the back of the cabinet.

20170515_210950_resized.jpg
The black wire connects to the Transfomer board at the back through this EMI Filter. Getting 118V on both sides of that. 20170515_211228_resized.jpg

But then I get a bit lost. It looks like the load side of the EMI filter go to the connector block underneath it, 20170515_211238_resized.jpg

The front of which has wires connected that look like they go down towards the front of the cab (power switch, service socket etc) which makes sense as the voltage up to that point is present whether the machine is switched on or off at the front, as long as it is plugged into the mains. 20170515_211249_001_resized.jpg

But I dont know where to check next to see whats going wrong.

I've measured the voltage on those 2 big caps at the back. Getting 11.88v on the Grey one at the back, but nothing on the front one. I think this one is supposed to be the 5v one, which would explain the board getting nothing as well, but where does the voltage go from 118v ac to 5v dc and will there be anything that I can check or replace to try and fix it?
 

Attachments

  • 20170515_183407.mp4
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Looking at the Power Diagram:
upload_2017-5-15_22-23-20.png

I can trace the mains through the power switch and then back into the same connector it goes out on but now its on Blu and Vio wires.

The Blu goes into the connector directly underneath it. The vio goes to the cloud I've scribbled in teh top right. Is that a relay in there? what is it doing? and how is that wired to the Capacitor on the output voltage? then that too goes back to the connector directly underneath.

This 2nd connector has a few wires a the front that go back into the connector. They dont go anywhere else, so Im guessing this is the voltage program plug?

Then the other cloud bottom left, what wires is my voltage on now? Going into the transformer. Then out of the transformer I'm looking at the two Blu wires which Im guessing is supposed to be 5V AC?

Then into the bridge rectifier and it comes out as 5V DC which should be orange/Blue and Yellow/black, which goes to the Cap again, before going to the connector that goes onto the main board.

If I've read that all right, where should I be testing next? and what should I be seeing?
 
Ignore last night. I was being an idiot. I was getting no power to everything because I'd left the coin door open and there is a cut off switch... :mad::oops:

So, tested voltages again tonight and I getting voltage on everything, but I stupidly thought if the board needs 5v it would get 5v from the power board. Nope. Power board is giving it 14.7v.

So back into the manual I find the schematic for the processor board and it shows this little circuit, which I hope is where it takes the input voltage and plays with it to give us the 5v that the rest of the board uses. Typically this is about the only bit of this schematic that is split over 2 pages and the bit in the middle isnt copied, so I've had to guess what it says.

But the important bit is the voltage over C34 which should be 5V.

I've measured mine and it is 4.83V. Is that good enough or will the board need it to be closer to 5V?

upload_2017-5-16_20-0-18.png
 
Cheers Phil, I'll happily try anyone at the minute. Any idea what Mark's username is?

I've put the playfield back in and getting the same result as yesterday. all going crazy. Reading where others have had the same issue they have suggested that it is the CPU constantly resetting. So assuming the 5V is close enough, it might be not getting the right info from the roms. Someone suggested removing them and resetting them. When I removed mine the legs were pretty much all black, so cleaned the legs with a fibre glass pencil and replaced.

Also removed the Processor and cleaned the legs on that in case that was the issue.

It's getting further now (I think) Coils not firing but lights are flashing still. Scores are flashing up still but they are trying to display what looks like an actual score rather than just random segments lighting up intermittently.

Put the logic probe onto Pin 40 (reset pin) which should be low if it is booting properly, and it is fluctuating from high to low repeatedly.

I'm now out of ideas, except maybe get some new roms burned. Has anyone got the kit to burn these roms? @Paul ?

If anyone has any other things for me to try, I'll give it a go.

Cheers.
 
It's best replace black legged chips and the chip holders...

You can cheat and put a better 5V on C34 (dont forget to put the other side on the earth) to see if that is the cause of the resets.
 

Tricky fix, the switch matrix and solenoid plugs were reversed at some point (Atari owners please put BIG labels on your plugs) causing a lot of damage which had been fixed before I received the board. The symptoms were that board was in reset all the time from an incorrect wake up on the watchdog circuit. Suspended the watchdog and replaced sockets on all previous work then repaired all the duff TTL chips (4) by using a logic probe to chase through the signals. Still in reset so restarted watchdog and resorted to Leon's test ROM, which showed everything working (Rats). Replaced games ROM's with new (still in reset) then tried a new CPU (long shot but I had one handy) as expected still in reset, in theory then it can only be the horribly rare and expensive static ram chips. Replaced with new RAM and that finally fixed the issue, both original chips were dead.
 
I'm sure middle earth has the biggest left sling shot rubber ever!

Atari games miss not having background sound. Believe the idea put forward by Ritchie/Jarvis for Superman was poo poo-ed by management.
 
I'm sure middle earth has the biggest left sling shot rubber ever!

Atari games miss not having background sound. Believe the idea put forward by Ritchie/Jarvis for Superman was poo poo-ed by management.

They possibly could have used an AY sound chip to loop a tune on the add on board triggered by the MPU but in those days it would have added significant cost and, at the time, there were still EM games in operation with no sound. And hey, when have pinball company finance executives ever gone with the designer ;-)
 
My first ever electronic pinball was a Middle Earth, bought from an arcade in Weston super Mare many years ago!

Glad it's all back up and running! :)
 
I'm a big fan of Atari video arcades from the 70's and the wiring in this pin looks very similar to the wiring of the video machines, in fact the OP's manual also looks very similar.

Glad you got it running again. :)
 
Haha, didn't notice the thread date last night, I've witnessed worse necro bumping than this before, it was worth a bump just for the Arari content which there seems to be very little of in the UK.

@DRD At least i wasn't asking if it was for sale! :rofl:
 
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I am resurrecting this thread because I have a similar voltage issue with a project Space Riders and am hoping someone can help out.

At power up the auxiliary board beeps and all light and displays flash. I do not have 5vdc at the MPU or power at the auxiliary board. The input connection at J9 pin 1 on the MPU should read 10vdc but registers close to 0. The lights in the cabinet bg are working.

Here is what I have done thus far to troubleshoot but the problem has not been solved.

1) rebuilt the power section of the MPU - new lm232, capacitors, etc.
2) rebuilt the power supply - new bridge rectifiers and the two large capacitors
3) reflowed solder connections coming off the transformer that connect to the fuse block
4) checked all fuses on the power board and at the cabinet plug.
5) checked continuity on the power/transformer assembly and from assembly to MPU connections and auxiliary board connections
6) showing no AC volts at the fuses and no DC volts coming off the rectifier
7) since the BG cabinet lights are working I am getting 117AC

Pulled the transformer to check for issues, none visible to but the design limits the level of inspection.

At this point the only thing really left is the transformer but those seldom go bad. I would welcome anyone thoughts.

Robert
 
........

Pulled the transformer to check for issues, none visible to but the design limits the level of inspection.

At this point the only thing really left is the transformer but those seldom go bad. I would welcome anyone thoughts.

Robert

Hi Robert

Transformers can go but it's very rare, have you checked your voltages from the transformer/PSU with a meter. Best to do this with the power connectors off the boards to start with - Dan posted some schematics above. The key one is the 5v across the input capacitor C34, so once you confirm your PSU is doing its job disconnect a the connectors from the main CPU board apart from the power one at the top of the board nearest the back of the cabinet (label them as it's easy to put them back in the wrong places or even upside down - see above). Then take the power connectors off the other boards and measure what you are getting across C34 when you turn it on. It should be 5v DC and less than 250mV AC.

Mark
 
The main thing is the AC volts from the Transformer, trace the wires from the transformer and measure for AC between the white and green wire, two red wires, the two yellow wires. the two violets (some are violet/green) wires and the two blues wires. They all should have AC at different levels. Some of the voltages such as on the red wires which drive the displays will be very high so be careful. M
 
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