DE Checkpoint

[prock]

I've been meaning to put some sort of re-build log online for a while now so I'm going to try doing it now. As some of you know I've picked up a DE Checkpoint which needs some TLC to get it into 100% playable state. This was the state of the machine when I picked it up:

• Display isn't working - it has been tested in another game and is working so something else is wrong here
  
• Playfield in bad need of new rubber and a complete shop out
  
• Playfield is missing some art and has some wear marks
  
• Ramp has some cracks in the entrance. Otherwise the ramp is in great shape. Should be easy to fix without being able to notice the fix.
  
• MPU not registering the flipper button presses
  
• Cabinet and backglass are in great shape
  
• Some obvious issues with some transistors on the MPU board in the "Lamp Return" section
  
• Machine turns on and plays (mostly)
  
• GI work
  
• Sound and speech work but has loud hum (common in these DE machines I hear)
  
• Missing the "Pivot Shaft" for the 3 bank drop targets
  
• Wheel in backglass spins as it should
  
• Cabinet shaker works
  
• GI wires are soldered directly to the power supply
  

That pretty much describes the state of the machine when I picked it up. I set it up in my basement and played around with it a bit. This is actually when I noticed that the MPU wasn't actually registering the flipper buttons. When you start a game you are able to change the type of music you are listening to but the music would never change. I downloaded the ROMs and started up pinmame and confirmed that when you start a game and press a flipper button a voice tells you the type of music you have selected. This wasn't working so I'm guessing the flipper buttons aren't being registered. This is kindof odd because the flippers themselves are working.

The first thing I wanted to do was get the display working so I started testing voltages that were going to the display board. All voltages were fine until I made my first mistake as a newb... I somehow managed to short out one of the high voltage line. This consequently blew something in the high voltage section of the power supply. So that will be the last time I do something like that. I've worked on a lot of low voltage electronics and they are much more resilient when it comes to shorting things out. In any case, lesson learned but now I had a power supply to fix. Searching online I found a bunch of replacement power supplies but decided to order all new components for the board. I knew it was only the high voltage section that needed to be replaced because all other voltages coming out of it were fine.

I spent hours pouring through the power supply schematics and part numbers at Digikey and managed to get a list of parts together. I knew some diods were bad in the high voltage section because I tested them all. I ended up ordering a full replacement of capacitors as well as a full set of diods and a full set of transistors (except for the 5v 2n6057 on the large heat sync as +5v is working fine) as well as a few resistors just in case and a molex connector for the GI. All said and done it was less than $50 for all the components with shipping. Most expensive components of course were the caps.

Now that I had all my parts I started de-soldering components on the power supply. This proved to be more difficult than I was used to because there was A LOT of heat damage on the back side of the power supply. All the traces were lifting because of all the heating and shrinking they were doing over the years. After much trial and error I managed to get a system together that allowed me to de-solder components without doing much additional damage but it was time consuming. I spent several hours just de-soldering components. The end result isn't exactly pretty but isn't too bad.

Turning the power supply on for the first time after replacing everything was a bit nerve racking. I carefully selected which connectors to plug in as to not risk any of the other boards. I turned it on and...... nothing was smoking... I could hear the transformer humming... I quickly tested all voltages and was back in business!!! All voltages are once again fine. Quite the adventure for one little slip with the voltmeter. Next I re-connected all connectors (including my new GI connector) and turned the machine on and was greeted with the bootup voice saying... "CHECKPOINT!". One thing that was immediately apparent was that the somewhat loud hum in the audio was pretty much completely gone. It was like night and day. So perhaps the slip-up with the voltmeter was actually a blessing in disguise!

While I was wading through all the power supply schematics I was slowly removing components from the playfield and cleaning them up. The playfield is pretty much completely bare now and has 3 layers of Mothers pure carnauba wax. I'm just waiting for my order from Marco to come in and I'll start putting the playfield back together. I can't wait! Oh and I couldn't find anywhere online that stocked the drop target pivot shaft so I got my Dad to manufacture one for me... problem solved

Unfortunately the display isn't working so next job is find myself a 20 pin ribbon cable (even if it's short) and test it again to eliminate the cable. If that doesn't work then my next project is to pour over the MPU schematics and build another shopping list for the display. Great fun!

I'll post some pictures eventually... just don't have any time to put them together at the moment.

[Malibu-ss]

I am pretty sure I tried a different ribbon cable

[prock]

How sure is pretty sure?

I spent a little time looking at the MPU schematics last night and today a bit. Turns out that the sound and the display rely on a lot of the same components and the sound is working.. soooo..... It could be the PIA chip however the CPU does a self check on boot up of all the PIA chips and no errors come back. That leaves me with a resistor arrays 21 and 22 along with a bunch of 470pf caps to replace. This is where a oscilloscope or logic analyzer would come in handy. Does anyone have one I can borrow or know of one I can get my hands on for an evening or two? It might save me a lot of headaches trying to track down a problem by randomly replacing parts.

[prock]

Here are some really bad pictures of my power supply. In the original image shown here:

You can see all the diods that I replaced. Diods D10 and D11 were bad but I replaced all diods in the picture regardless. I replaced C4 (the really big one, replaced with 4 smaller ones), C10, C11, C12, and C13 as well. All resistors tested okay so I left them alone. I also replaced TR1, TR2, TR3, and TR4. If you look closely you can see all the heat damage in the high voltage section as well as on some of the traces. In any case here is what it looks like now:

I may replace the 12V regulated section one day because I have the parts but it's working so I'm going to leave it alone for now. Also worth noting but not shown is the new GI connector which I installed an is working fine.

I began re-building the flipper board last night and started at the power (+50v) side of things working my way backwards. I'm about half way re-building it. I'm currently working on replacing all the transistors which there are a lot of. I really wish I has a method to test them as opposed to replacing them all... they are cheap so why not I suppose. De-soldering is a bit less painless now as I got a good process but it's still pretty time consuming. Hopefully I can get it all done tonight and will have some working flippers again.

[prock]

Flipper board has been completely re-built now and working like a champ. The MPU is still not detecting the flipper button presses but at least now I'm sure that it has nothing to do with the flipper board. I'm not going to worry about it until I get the display working. Oh did I mention I had to re-build the flipper boards because of my slipup with the voltmeter? Flippers stopped working completely after that. Turns out it was the NAND gate ICs which got fried. Guess I can now be happy that the flippers are working and with mostly new components on the flipper board to boot. So I think now I'm finally back at square one.

[prock]

I've been thinking about my logic analyzer problem. I need a way to confirm that signals are getting to the display board through the ribbon cable. The most ideal solution is to get my hands on a commercial logic analyzer somehow but I doubt I'll be able to do that. After much thought and searching online I found devices which are made to do exactly what I need them to do, confirm that logic is getting to the display board. They are called logic probes and cost about $50 here in Winnipeg. Rather than spending the $50 I started thinking about building my own with components that I happen to have kicking around. I found this: http://code.google.com/p/arduinoscope/ As luck would have it I have an arduino so I'm golden. I'll be setting my arduino up as a logic probe this weekend and hopefully narrow the problem down.

[prock]

I got the arduino acting as a 6 channel logic probe yesterday. Works pretty good for what I need it for. As a result I have confirmed that the ribbon cable is working. I could see the blanking pin going on and off when I turned the machine on. If I left the coin door closed I could see some logic being passed to the display however I'm not sure of the protocol and can only monitor 6 pins at a time so I am unable to confirm if it's valid or not. If I opened and closed the coin door and started a game I didn't notice any logic on the cable at all so I'm not sure if the analyzer is fast enough or not. The arduino I have funas at 16MHz so I'm assuming it should be. I might have to go a step further and monitor only one pin at a time to ensure it's fast enough.

To confirm I was getting valid results I unplugged the ribbon cable going to the audio board and monitored that for a while. I got some really good results from that and could see the high/low values as different sounds were queued to play. Pretty cool.

I noticed that with the audio ribbon cable unplugged it played the "Checkpoint" audio anyway. I'm assuming that's just programmed into the audio board to do that. That got me thinking, shouldn't the display board do the same thing? Would it display something even though the ribbon cable is unplugged when the power gets turned on? Anyone with a DE machine that can confirm this for me? If that is the case than it's probably safe to assume there is something wrong with the display board... Perhaps the EPROM? Although I haven't ruled out the MPU yet I've ordered a new eprom set for the display and hope to get that this week. It's cheap so why not.

[Malibu-ss]

I can try it with my Star Trek tonight and let you know

[prock]

Awesome, thanks man!

[Malibu-ss]

Ok.....I disconnected the ribbon cable from the DMD on Star Trek.
The game would not even boot up without it plugged in.

Very weird

[prock]

hmmm yeah.. very odd. When I turn Checkpoint on with the coin door closed the GI all turn on and I get the "Checkpoint" sound but then all lights shut off and stay off. When I open the coin door everything turns on again.. I add a few credits using the switches and I can start a game (doesn't matter if the door is open or closed at this point).

[prock]

Got my new EPROMs yesterday but had company over and couldn't test it. Put it in just now and I now have a working display! It looks awesome! Cant wait to put this thing back together... marco order came in with all the parts. Guess what I'll be doing this weekend!

[prock]

I can now explain whats happening on my Checkpoint. When I turn it the display flashes "open door" until I open the coin door. As soon as I do that I get the "insert coins" screen and it goes into attract mode. When I push the service buttons I get a loud "boing" sound that plays each time I press the button. It takes some time to scroll through the screens because of that. I have to read the manual because I'm unsure of why it wants me to open the door right away. Perhaps because there are no batteries in it? I also need to figure out how to go into test mode so I can test everything before putting it back together. I'm so pumped right now!

[Malibu-ss]

awesome dude!!
open door is because you have no batteries in the game

[prock]

This may sound weird but I cannot get into diagnostics mode. I had about 5 minutes to look at it tonight and wanted to run through the diags. I followed the manual... turn it on, open coin door, set the FORWARD/REVERSE button to REVERSE (down) and press the STEP button.... I keep getting into audit mode. I installed batteries and no longer get the issue where it wants me to open the door when I turn the game on. Any ideas? I should probably check the switch for proper operation first but lets assume it is working as it should. I still get a loud "boing" sound when going through the audit screens. I also noticed that the forward/reverse button seems to have no effect when I'm going through the audit functions.

EDIT: Tested the switch and it is operational. Up=on, down=off. Need to trace the wires back to the board and ensure that I have connectivity to the board. Guess this is where the fun really begins.

[Malibu-ss]

maybe the little switch is no good............I have had it happen

[prock]

I tested it this morning.. seems to be working. When the switch is in the up position there is connectivity, when it's down there is no connectivity. I'll dig a little today and see if I can find any info online regarding this.

[Malibu-ss]

try entering the test menu with the button down,then try with the button up......it should let you in different modes that way

[prock]

I had tried that this morning... Either Up or DOWN has no effect.. I always end up in the audit screens. After looking at the schematics I found that CN14 is where the diag switch wires run to... I'll do some connectivity testing tonight to ensure the wires are good and there are no shorts. I'd imagine they are but better test them in case.

[prock]

Managed to get the pin mostly put together this weekend. Having some fun with the plastics under the ramp to try and figure out where everything goes. I have some good video footage so just have to wade through that. Guess you can never have enough pictures.

I got the diagnostics working today. All I needed to do was re-seat the coin door plug just inside the coin door. I had already re-seated the plug at the MPU so I knew it wasn't that. Most things checked out okay. Couple known problems like a row of bulbs that are out because of a blown transistor and of course the knocker solenoid doesn't fire (cause it's not there).

The other problem that showed up was a string of flashers not working. I had purchased some 63 bulbs to replace some flashers but is seems that the flasher circuit for that string is outputting too much voltage as it burns the bulb each time I put a new bulb in. The whole string of flashers was burned so I imagine it was a problem from before. On a side note it turns out I need some other flashers as well... 63 is the turn type bulb.. I need something like 555 but the flasher version (don't know the number offhand).

Sooooon it will be playable... very soon!

[Malibu-ss]

you are probably needing 906 bulbs

[prock]

Yup... #906 are the ones. I've got some on their way to this end of town so that should fix things up. On a side note #63 bulbs were the wrong bulbs... needed #89. Explains why they burned right away..

Quick update... got the machine almost back together. I have one plastic to put on above the ramp and some wires to solder back to some light sockets and a switch. I have to find some screws to mount the knocker solenoid. Also have a bit more soldering on the MPU to get the row of lights working. Need to install the pivot shaft on the 3 bank drop targets as well. I'm getting there....

I managed to play one game last night and it plays pretty well, might have some tweaking to do here and there. Super fun game.. I have not idea what I was doing as far as rules go but I got a multiball going and ended up with about 2 million points. Not bad for missing one of them ball speed switches (the switch I need to re-solder).

[Malibu-ss]

awesome...........I can not wait to play it!!

[paulohotline]

Congrats dude, rules are here:

http://pinball.org/rules/checkpoint.html

[prock]

Thanks Paulo for the ruleset. I gave it a read through yesterday. Pretty straight forward.

Just wanted to report that the game is now alive! and 100% playable. I banged out a couple games last night and tweaked a few things. All drop targets are operational, all switches are working (couple need some tweaks). Only things left are to get the light row working and to mount the kicker solenoid... oh and install a few new flasher bulbs. The game looks really good all lit up, there were tons of bad bulbs. I'm considering ordering some LEDs to bring out some colors... I find the back box might benefit from some super bright cool white LEDs to brighten it up a bit. It seems they used a lot of paint so it's pretty dark. It's an amazing back glass so I definitely want to highlight it.

Hopefully tonight I'll actually get to play a few more serious games on the machine so I can at least get my name on the high score list!

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