Mirco Challenge 4 Player Pong Repair Log

Kaizen

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Donor 2015
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I've had this cab for a couple of years now, I won it on an Ebay auction and had it shipped up from Melbourne to Brisbane (Australia).

http://www.arcade-museum.com/C/Challenge.html


Video of the game play.

https://www.youtube.com/watch?v=KQ-Mz5B-uCs

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It was working when I got it but it's been stored away since then, waiting for a cosmetic restoration. A friend of mine also has one with a faulty PCB which he dropped off for me to have a look at for him.
I dusted the cobwebs off and powered it up to check both boards.

My board has issues with the paddles, the right side has them doubled up and the ball is missing when you try to start a game.

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My friend's board was totally dead.

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The crystal was working but the 7404 directly below it was faulty, I replaced it but there are further issues.
A quick check of the voltage (+5v only on these boards) and it was sitting at 6.38 vDC. One of the four 5k pots had corrosion on the connector and they were all a bit scratchy.
Rather than working on top of the cab, I decided to get it onto the test bench.
I have a 3.5" reversing camera monitor with AV (composite) input and runs off 12v the board only required 5v so I used a PC power supply to run both.

Four new 5k pots and a couple of switches completed the setup but I didn't have any of the connectors that plug onto the board so I soldered all the connections for the controls to the underside of the board. Power and video were connected via modified crimp connectors so I could still swap between boards.

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I've started to write up a pinout, theres no schematics in the manual that came with it which I've scanned and uploaded to KLOV.

http://www.arcade-museum.com/manuals-videogames/M/Micro Games Inc Challenge Service Manual.pdf


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There's going to be that one guy down the road who is extremely grateful for this. Thanks for posting
 
While doing research on it I can see there a lot of posts from looking for help with this machine and not a lot of documentation is available.
Having the correct pinout will certainly help especially if you only have a PCB.
 
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I've made a little bit of progress on my PCB this morning, I found two 7400's with stuck outputs (2A & 2F).
I socketed and replaced the IC's at both locations with no change. I also cleaned up a previous repair at 3C.
After a bit more probing I found another 7400 at 5E with a stuck output, replacing that has brought the ball back into play.

https://www.youtube.com/watch?v=JE7RuxeRbaM

The ball won't rebound of the bats or lower border so there's still plenty of work to do...
Scoring is working fine, there's still the issue of the bats on the right side being doubled up.

I've cleaned the pinout up and uploaded it to the Mirco Challenge KLOV page.

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I had been trying to get my PCB to a fully working state so I could take references to compare with the totally dead board.
After a few hours I thought I'd take a break to see if I could at least get my friends board to a state where it's putting out some video on screen. After getting him to check the voltage on his cab, he found that there was no +5v DC volt supply. Hmm... not good.
The first thing was to go over the tracks and check for any damage, I repaired some obvious broken tracks that were caused by the board being scratched.
The board had been messed with by someone (around 1992 by the date code on the 555's that were replaced) before he got it so I thought it prudent to recheck their work as the quality of the repairs was a little average. I started with the capacitors that had been replaced.
The first cap I checked at 3H had the wrong value, 100uF compared to my board which still had the original caps in place which was 5uF.
I found another at 9F which was 220uF and on my board it was 35uF then next to the P2 plug there was a 220uF instead of 33uF.
This cap was connected in reverse across the +5v and Ground where the supply enters the board and had let the magic smoke out, fortunately it was the newer vented type and didn't go into nuclear meltdown.
How do you miss that big arrow with a - pointing to the + on the PCB ??

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That probably explains why his power supply wasn't putting any voltage out.
 
I'd like to look at a few different 4 player Pong schematics for comparison of the way the different sections of the boards are put together, I believe most were copied from the original Atari Pong schematic with a few modifications for the 4 players.
I've had a look at the Midway Winner drawing but I was hoping a few people here might share whatever 4 player Pong schematics they have.
TIA
 
After about 15 hours working on my friends board I've had some success. I still need to work out an issue with the 4 Player side of the game, the second set of bats don't become visible when you add a second credit but the 2 Player game is now working perfectly except that the ball speed is supposed to increase after hitting the bats a few times.

I foung 11 faulty chips so far and a few 9316s (74161) that read as 74163 on my tester whereas brand new ones read 74161. A couple of them were running hot so I replaced them anyway so possibly 16 faulty chips.

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https://youtu.be/blurrkF4G4A

I haven't tested the sound yet and will wait until I get the board plugged back into my cab but I need to sort out the voltage regulator issue before I do that. It was running at 6.38v when I checked it earlier this week.
 
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I have a Atari Pong Doubles and 2 boards, one partly works and the other is untested I need to get to one day. I do have a PDF of the schematics and wiring harness which I'll try to post here and a picture of one of my boards. Maybe it will help but it's clearly a different board layout.

Ok it would not let me upload the PDF so I took a screen shot so I could up load it here. If you would like the PDF send me your Email in a PM and I will send it to you.
Well it seems it loaded the PDF after all but I'll post the jpgs anyway.
 

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Thanks for taking the time and effort, much appreciated.

This PCB repair is now completed, all functions have been restored.
The speed up occurs at hit 4 and again at hit 12, the game really becomes brutal at that speed.

https://www.youtube.com/watch?v=cpt4xfP276s

I worked out why there was no increase in ball speed, at some stage someone decided it was too difficult at the faster speed and disabled it by adding two jumpers, see image below.

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The entire board containing over 90 chips will now be socketed allowing for easy replacement and testing of chips in the future.
All the 40 year old chips will also be replaced with new ones and hopefully this thing will keep going for another 40 years.
One of the most challenging parts of this repair was reading the chip numbers, they are mostly manufactured in 1974 so all date codes start with a 74. Easy to get caught out when you have a date code of 7404 and the chip is a 7408.
 
There's going to be that one guy down the road who is extremely grateful for this. Thanks for posting

That guy is me. Picked up one of these as a throw-in for a bulk game buy I helped with recently and this thread helped me troubleshoot and get it working. Turns out that the board worked fine, one pot needed to be replaced and monitor needed new caps. This thread, and the pinout in particular, were super helpful. Thanks!
 
Glad it was of some assistance, repair logs are an essential part of getting some of these old games that have little to no information available back up and running.
I appreciate the work that others have done in providing a record of their repairs and do my best to reciprocate where possible.
 
I own one of these! It was listed on Craigslist as PONG TABLE for $40. The guy said it worked great. I drive the 30 minutes into town and he calls me and says "I'm sorry Jeff, I thought it worked fine but when I plugged it in the screen is all messed up."

No problem. I still want to see it.

I take a look, he says "$20 and it's yours." I buy it, and never even plug it in to try it. When I get home, sure enough, the screen is all messed up. Horizontal hold. One tiny tweak and she looked flawless.

Just last week I replaced two of the original 5k pots on the player 2 side because they were jittery. Took the new pots just fine. It's honestly one of my favorite machines. It's classic, timeless, difficult, and 4 people can play. AND you can totally spill a beer on it with no worries.
 
Need help switching to 4 player

I just picked one of these up and it was converted to free play. It will start 1 and 2 player games, but will not start 4 player. I assume this is because 4 player was activated on the 2nd coin. Looking at the game wiring I don't see any modifications that would have been done to make it free play. Any advise is appreciated!
 
There is a picture in the first post that shows the pinout of connector p4. It looks like free play is toggled from there. Maybe it's jumped or there is a toggle switch?

Edit: sorry just looks to be for leds
 
Thanks for your response. Connector 4 is for the led display for the free game feature. Connector 3 goes to the coin mech. I did notice the orange wire on this connector was different then the diagram. It was pinned in the middle so I moved it to match the diagram but still no luck.
 
Wish this thread was around when I still owned mine. It worked, except for the player Pots.

As for the free play issue, how is it setup for free play? It is a button or switch to mimic the coin drop? If so, can you trigger it again?
 
Wish this thread was around when I still owned mine. It worked, except for the player Pots.

As for the free play issue, how is it setup for free play? It is a button or switch to mimic the coin drop? If so, can you trigger it again?

It starts a game without a credit by hitting the start button. Some how the game is set to free play but I don't see anything jumped. I suspect if I could get the game back to getting credits I could get it to go into 4 player on the 2nd credit.
 
and now I've got one of these in my garage. When it arrived the speaker was disconnected and now I know why. It sounds like its playing the "score" sound constantly, one forever buzzzzzzzz. I can coin it up and the scores do zero out but I never see the ball, only see one paddle (when its set to player vs game mode) and I cant start a game.

No schematics, pre-cpu. UGH....
 
Still trying to figure out why I've got the constant buzz through the speaker and no ball on the screen. I did find a bad 161 at 5g but changing it made no difference. I'm not keen on shotgunning boards but without schematics or an idea as to what part of the board generates the ball that might be my only choice.
 
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