(Topic ID: 222839)

Help! Totally stumped. AC/DC Cannon motor

By TimeBandit

5 years ago

Topic Stats

14 posts
6 Pinsiders participating
Latest reply 5 years ago by Rensh
No one calls this topic a favorite

You

You are not signed in!

Find in topic

Linked Games

AC/DC (Pro) Stern, 2012

Topic Gallery

View topic image gallery

You're currently viewing posts by Pinsider TimeBandit.
Click here to go back to viewing the entire thread.

I have two AC/DC pros.

On one of them the cannon motor doesn't work. Neither during a game nor in test.

If I switch the CPU boards the problem follows the CPU board to the other machine.

Everything else on both machines is fine.

There is something on the CPU board that is affecting ONLY the motor.

What is it?? I have poured over the schematics for hours and can't get there. I've tried to get the scope onto the main CPU pins but I'm not 100% sure I have the right pin anyway, and it's all getting a bit tedious.

I'm sure someone smarter than me has a good idea.

Anyone want to chime in?

I thought maybe that initially but I have discounted it a couple of different ways. Switches are definitely not involved.

My last test had only the plugs connected on the entire board set that are required for the motor to operate in test mode. No switches connected except the coin door switches, and no lamps. One CPU board worked. One didn’t.

I think it goes all the way back to the CPU, but I want to confirm that theory of operation says there is one pin there just to drive the motor.

I probably should give a bit more info on what I have tested so far..

I have had the scope all the way back to U5 looking for a drive signal and I’m not getting one. So no, no signal at Q32. Everything else on the same chip is fine. I actually replaced U5 just to be sure.

My strategy at the moment is to just follow the signal path back until I hit the CPU. And that’s sort of what I want to confirm is the right thing to do.

I even connected the bad cannon across to the good machine, and it worked fine in test. So there is nothing wrong with the motor, or the power.

Quoted from herg:
The circuit that drives the motor is CPU bus -> power driver board -> HCT273 latch -> Q32 transistor. There is not a single pin on the CPU board that could fail that would only affect the canon motor.

Thanks Herg, that’s exactly what I was afraid of.

Quoted from pinballaddicted:
[quoted image][quoted image][quoted image]
We had a similar issue on a Stern driver board. With outstanding help from Chas at Stern and Ken from Lake Macquarie, we isolated the issue to that chip (1st photo). That particular chip is on both the driver and CPU boards. I cannot let go of stuff unless I work out what caused the issue. Our machine had a shaker motor fitted without the in line filter (pic 2). Electrical noise from the shaker motor stuffed that microprocessor and one circuit was locked on. It took a long time to do it but I feel this was the culprit. Before you do anything, change over the chip (pic 3) and reset the entire machine to see if you still have the same issue. Check the tracks and continuity of all connections for this circuit. I am assuming you had already checked all other circuits that are associated with that faulty one. I am also assuming, that you have isolated that there is no signal from the CPU board and the issue is not with the driver board (you swapped out the driver boards first).
I cannot find anyone is Australia with a test bench to test and repair this board. If you find one, please let me know. We have a few boards that we would like to be repaired. People keep posting how good SAM is and how bulletproof it is, well I think maybe not so, especially if the machine has mods. It worked out more economical for us to buy a new board than send our old board to Ks arcade (USA) for repair. Honestly the most economical and fastest place to buy the board is from Pinball Life, you will have it in less than 2 weeks. We bought ours from AMD to keep a good relationship going with them as they have always looked after us.
Good Luck!

Thanks for your input. I appreciate it.

First thing..I can probably repair your boards for you. I have all that stuff covered. PM me with more details if you like.

Second thing is ...... SOLVED.

I'm not really embarrassed by how easy the fix was, as I believe I have been pranked, haha. But still, I should have checked this but sometimes you just don't go to the easiest thing first for some strange mental block thing. Can you see where I'm going with this?....Yes, the cannon was disabled in the menus.

Sorry to create a useless thread, but maybe just the age old warning reiterated. Start with the easiest stuff first, lol.

Can you believe I changed U5??!!

Promoted items from Pinside Marketplace and Pinside Shops!

You're currently viewing posts by Pinsider TimeBandit.
Click here to go back to viewing the entire thread.

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!

Help – Contact – About Pinside – Support Pinside – Top