02/26/2017 – 24V SMPS with Power Filter

Ooooh, look at the cool things that wordpress does.  If I add three pictures at a time, it will put them in this weird box with all three pictures at a time.

Let’s start with the picture on the bottom left.  That is what the backbox of SS3 used to look like.  You can see the four PC power supplies at the top that are all tied together to produce a mega 48V power supply.  To get that to happen I used the Max Power board to tie it all together.  It worked fantastic, but there was a lot of fan noise (I bought really cheap Diablotek power supplies hoping they would be pretty good quality, but their fans sometimes made a nasty screeching noise.  It was actually so bad, somebody at Pintastic the first year pull the power because they were worried something was going wrong.)

Top right picture is with all the extra stuff removed.  This is getting ready to install the 24V SMPS from China.

The big picture is the final installation.  The 24V SMPS is on the right hand side.  It is connected using a 6 pin Molex connector to the power filter board.  That board makes sure that the cold charging of the capacitors isn’t detected as a short and shut down the power supply.  It works fabulously.  The power filter board also has the ability for a processor to read if the power supply is powered on, can turn the power to the pinball machine on or off by grounding a pin allowing the processor to easily control the high voltage power supply, and a handy dandy LED to tell you when the big caps are charged, and can give you a shock.  The power filter board can be used for two different voltages, but in my configuration, since I only have 24V, I have tied both sides together with jumper wires.  That provides the most amount of bulk capacitance which reduces the instantaneous draw from the power supply when solenoids are fired.  It seems to work really well.

I have talked to the Mezels and they are going to have the power filter boards available for $5.  Currently they don’t have a picture up.  Fast makes a similar board for $120 which is a much better design, but for $5 for the board, plus $15 in parts, you can’t beat the OPP version.  I will eventually add information to the Pinball Makers website when I get time.  I’m busy, busy, busy right now trying to keep stuff moving towards Pintastic 2017.

I’m hoping to do another talk at Pintastic this year.  As I have said before, this is the last Pintastic talk I’m planning to give.  Hopefully it will be a fitting end to this project, and it can live on.

Back to SS3.  So right now everything is working except for the drop target reset.  Since I moved from 48V to 24V, I’ve needed to adjust the initial kicks for all of the different solenoids.  That only took an hour or two to dial each of those in.  The one problem that I have is the drop target.  I can not seem to generate enough power to reset the drop target if all the drops are down.

So when rebuilding that drop target bank originally, most of the drop targets were broken.  I bought new replacements from Steve Young from Pinball Resource, but they were not exact matches.  One issue is that they are slightly taller which forces the springs to be pulled a little bit more taught and requires more force to reset the drops.  Probably wouldn’t be an issue if it was only one or two targets, but since I replaced all seven, each little bit of extra needed force starts to add up.  I also had to replace a couple of the springs that were missing.  I used springs that were as close as possible, but it seems like they might not have been close enough.

At this point, I’m going to take another hour or so trying to adjust the springs to get the reset to work properly.  If that doesn’t work, I think that I’m going down the route of removing some of the turns from the coil to give it a little more umph.  That is a last resort, but I might need to do it to get it to work reliably.

Hopefully in the next week or two I will put up another video of SS3 running at 24V.  It seems to be playing pretty well, but without the drop targets working properly, it didn’t seem useful.

2/15/2017 – Weekend of Suck

Yeah, everybody likes to send out blogs that say how great things are going, and how everything is peachy fine.  Well, last weekend was not that way for me.  Everything that could have gone wrong, did go wrong, and now I’m further back than where I started.

So the big plan was to switch over the power supplies from the four PC power supplies to a single cheap 24V switched mode power supply from China.  The previous week leading up to the weekend, I had soldered everything up, set up all the connectors so I could plug things in, and I was all set to go starting on Friday night.

I plug in the 24V supply, unplug everything else, and start testing.  Flippers work perfectly.  Drop target doesn’t reset, but that is expected because I haven’t changed the timings on the pulses.  Kickout hole, same thing.  Everything is looking great…but here is where things go south.

I think to myself…hey, I have a 36V power supply sitting here.  Why not toss that in and see what happens.  Instead of slowly building things up from a known base, and actually having the machine run on the original 24V that the machine used, I decided that I would add 50% more voltage and with ohms law, yes, 50% more current.  I switch to that power supply hit the flippers a couple of times, and then, all of a sudden, one of the flippers locks on.  Ahhhhhhh.  I pull the power quickly.

OK, guess I will simply desolder that MOSFET and put a new one in.  I “guess” at which MOSFET that I need to replace, and guess incorrectly.  That means I just spent an hour replacing a MOSFET that didn’t need to be replaced, and the board still doesn’t work because there is still one MOSFET that needs to be replaced.  Why didn’t I bother to pull out a schematic?  (Yeah, I knew that it was one of two MOSFETs on that side of the connector, but damn it, I guessed the wrong one!)

After that second failure, I was just mad at myself, mad at pinball, just simply in a bad mood and I couldn’t work on pinball for the rest of the weekend.  I just needed to take a small break from it.

Here is the thing that really irks me.  I knew that throwing 36V through the flippers caused too much current for the MOSFET.  I knew that from when I first brought up the playfield, assumed it was 43V, and only later looked at the manual and found out that it originally ran at 24V.  If I would have simply taken a step back, and thought about what I was doing and not rushed into it, I would have been OK, and could have saved myself a couple hours from replacing the parts.  That’s what angered me the most.  That I just didn’t take the time.  I rushed a decision, and now I am paying for it with extra work.  It teaches me for being a dope.

Luckily there was a ton of snow this weekend, so I could cool off by going out and building a large igloo in the back yard.  Come to think of it, I’m still angry at myself.

2/4/2017 – Automated OPP firmware updates

Previously, to update multiple OPP cards attached together in a chain, each card would need to be updated one at a time.  To do that, a ribbon cable connector would need to be unplugged and a jumper would need to be placed to make it so an individual card could be addressed.  While it only takes about 5 minutes to update four cards, it is a pain in the rump to switch around the connectors.  (Especially when the playfield is installed in a machine).

In the repository, version supports a new RS232 command called upgrade other cards.  That allows the card to pass through all RS232 communication so another card can be updated.  What does that mean?  After updating to this version of the firmware, all future updates of firmware can be done without moving cables.  Yeah!

Here is the new command:  c:\Python27\python.exe Gen2Test.py -port=COM5 -upgrade

You may notice that the version is  I use the following method to name code releases.  Major.minor.engineering.test.  So for this version of code, the major release = 0, minor release = 2, engineering release = 0, and test release = 1.  The important thing to note here is that the test release is non-zero which means that I haven’t done a full regression test on this version of firmware.  After that testing is done, I will change some of the first three numbers, and the test number will go to 0.  Basically, if the last number is 0, a full set of regression tests have been run.  If non-zero, development tests have been run to prove out the new feature, but the validity of the code can’t be guaranteed.

So why didn’t I do a full regression test?  Well it takes me approximately 1/2 hour to run the tests, and it involves using test fixtures which I have to set up.  Since, said test fixtures normally live in a box, out of the way, I don’t want to take the time to run those tests now.  I also know that there are a bunch of new features that I’m going to be adding in the next few weeks.  I will simply hold off running the regression tests until all of the immediate changes are implemented.

The next version of code will not be very interesting to many people because it will be supporting the high side incandescent driver boards.  (I believe I am the only one running those boards at this moment.  Right now, when the Pinball Framework instructs them to turn on, they turn off, and vice-versa).  That is the code needed for SS3 to fix its light displays.

1/29/2017 – Well, Goodbye Dolly!

Many times I write lines like above, and wonder what people who don’t speak English as their native language think about them.  I would say, 60 or 70% of readers are native English speakers.  That means that 30-40% of the people reading the site are probably going through some sort of translation service to read what I’m writing.  The title of this blog post is referring to a Broadway musical called “Hello, Dolly!”  Truth be told, I’ve never seen “Hello, Dolly”, so it probably doesn’t matter and it really has no bearing on pinball, or what I’m going to talk about in this post.  But there it is, so now everyone knows.

I remembered to take before pictures today.  (Usually I simply wish that I had taken before pictures, and then realize that I haven’t taken any.  Luckily, today I remembered).  This will be the last time it looks like a Dolly Parton machine.  I respect Dolly as a person, but really, I dislike her music immensely.  She does a lot of things with helping under privileged kids, such as  sending free books once a month when they are young.  She also donated a lot of money for disaster relief when the fires hit Pigeon Forge, Tennessee.  Before starting this, I spent an hour trying to find five or six songs that I liked, but I couldn’t find anything.  That means it is time for a retheme.

Let the pictures begin:

Little bit of damage on the cabinet, here and there.  The playfield is down to the bare wood.  I do love the Susan B Anthony dollar coin symbol, so that is staying.

Here are pictures of the backglass and the damage to it.  Lots of flaking especially around the dress area.


Old boards in Backbox

Here are all the old boards.  There is a lot of acid damage on the MPU board.  All four of these boards will be replaced with OPP boards and the Bally interface board.  There is probably going to be a Raspberry Pi to power it all.

So I started the tear down of the Dolly Parton machine this weekend.  I have a new thing that I hate to do in pinball.  It is trying to remove side rails.  What a pain in the butt.  There is simply no good, nor easy way to do it.  The new theme requires me to repaint the whole cabinet.  That means stripping the cabinet down completely.

Removing side rails requires using diagonal cutters to rotate the threaded nails that hold on the side rails, and slowly back them out.  The edge of the nail head is nearly flush with the cabinet, so every single nail takes a long time.  You are also trying to be very careful to not scratch the stainless steel rails because I’m going to reuse them in the final machine.  Because the nails are so flush with the cabinet, it is very difficult.  The diagonal cutters work well because they have tips that allow you to get on the edges, and grip the side of the nail heads.  The whole process takes me anywhere from five minutes to remove a nail, to a half hour if things go poorly.  Lot’s of time.

Right now one side rail is off, the cabinet door has been removed, and there are only six more nails in the other side rail.  The cabinet is in better shape than the Sharpe Shooter cabinet, and I won’t need to modify it to get parts from other manufacturers to work in it.  All of that points to some easier aspects in the retheme.

The retheme is a little incognito but if you search around on the web, Joe posted it somewhere that I won’t mention.  Joe Zenkus is doing the art work for this retheme because he is the busiest guy in pinball.  That’s all I have for today.  Thanks, as always Joe!

1/19/2017 – PwrFilter/Bally Intf boards received

Yesterday the boards came in from ITeadStudio.  Their newest cheap shipping option (SF E-Parcel) is really fast.  So I ordered the boards on 1/5/2017 (yeah, it was late Thursday night).  They shipped the boards on 1/12/2017.  I received the boards on 1/18/2017.  That’s about a two week turn including shipping which is really fast.  The shipping was only about $14 for two sets (10 boards) of 10cm x 10cm boards.  Nice!  Unfortunately my cheap 36V SMPS power supply hasn’t arrived yet, but as soon as that gets here, I can do some quick testing on the power filter board.  It is such a simple board that it should only take a day to verify it is working properly.

I built up a filter board tonight and took a couple pictures.  I’m happy after visually inspecting the boards, and look forward to getting the power supply to test even further.  This should clean up the back box of SS3 and make it quieter (the 4 cheap PC power supplies that I used have very loud fans.  It doesn’t matter when the glass is in the backbox, but when debugging, the fan noise is bothersome.)  I must also say, that I’m really sick of listening to the theme song to “The Good, The Bad and The Ugly”.  When playing, a game, it plays continuously on a loop.  I think that I could sing it in my sleep at this point.

The power filter board can be used to add bulk cap to 2 voltages or to 1 voltage.  (plated through holes are provided to tie the two planes together if the board is only used for a single voltage which is the configuration that I built up).  In that case, you only need one NTC thermistor, and one PChannel FET.  In the two voltage situation, you need two of those parts.  The board should insure that the SMPS will not incorrectly detect a spike when flippers are activated.


Populated power filter board. Shows input connector and NTC thermistor.


Populated power filter board. Shows filtered output connector and interface connector.

The bottom 6 pin connector contains 3 pins for each of the voltage sections.  For each section, one pin is ground, and the other pin enables the PChannel FET if it is grounded.  That can be controlled by a processor, or if you want to always have the voltage on, you can just use a 100 mil jumper between the ground pin and the PChannel FET.  If you want it to act like a normal pinball machine, you can add a normally closed switch on the cabinet door, and when the door is opened it breaks the connection and disables the high power voltage.  The last pin provides a digital output that can be read by a processor to check if the voltage is enabled.  (Just a simple voltage divider to provide the appropriate voltage for your processor).  That allows a message to be printed on an LCD screen or whatever.  Hey, the board even has two indicator LEDs to indicate that the voltage is hot.

I also now have all the parts for the Dolly retheme.  It is going to take a couple days for me to build up the OPP boards, but since I just received the Bally interface boards, nothing is stopping me from starting on that machine.  I’m currently moving faster on that machine than I was expecting.  Below is the blurriest picture ever to be added as part of a blog.  (Sorry).  I didn’t realize it was so blurry until after I took it off the camera, and I was too lazy to take another picture.


Bally interface board to OPP board

The large slashes through the connectors done in silkscreen note the pins on the connectors that are keyed.  That should make it easier to plug and unplug connectors because you can scan the key in the connector and line it right up.  That board hasn’t been populated yet.

01/14/2017 – New video of SS3 game play

Just a quick note that a new video was posted on the youtube channel.  SS3 is now playable.  Yes!  I’ll continue to work on it for the next few months so that it is much more polished than the last time that it was seen at Pintastic 2015.

Besides that, just received the parts for populating the filter power boards, and for redoing the Dolly machine.  I received a note from ITeadStudio that my boards shipped, so I should receive those in the next one or two weeks.  The new single power supply has been ordered to make SS3 run on a 36V SMPS and a single PC power supply instead of the 5 PC power supplies that it currently runs on.

Have a great weekend.

1/5/2017 – Filter and Bally Intf PCBs ordered

So the Power Supply filter boards, and Bally Interface boards got ordered today.  I was holding off on the order to save a little bit of money on the shipping from IteadStudio.  (Hey, a buck is a buck, right?)  I wanted to get them out this week, because Chinese New Year starts on 1/22/2016 and that closes the factories down for about 2 weeks.  By ordering this week it should give them plenty of time to ship the boards before that holiday hits.

So what the heck is the Bally Interface board alluded too by the title?  As you may recall, I have a Dolly Parton machine that I’ve been meaning to do a retheme.  The MPU board in it has massive amounts of acid damage, so that needs to be replaced.  (I actually bought a replacement board in Allentown about 5 years ago, but never bothered installing it.)  In the end, if I simply replace the MPU, I will have a working Dolly Parton with a completely destroyed playfield, and a backglass that is falling apart.  Sounds like a perfect machine to do a retheme so I can sand the playfield down to bare wood, replace the backglass with an LCD, and add some more rules to give a little more depth to the game.

Problem is that I don’t want to rewire the machine.  I had it up and running a bunch of years ago, and it was working at that point.  It booted and played, two of the five displays worked, etc.  Replacing the two displays would cost about as much as just throwing in an LCD monitor, so that is a no brainer.  Adding new rules requires a new MPU, so I might as well update it to use OPP boards to drive the machine.  That requires converting from the backbox boards in the cabinet to OPP boards.

The backbox of Dolly Parton has a transformer board.  (I’m not going to change anything on that board, and use it as is).  Then there is a lamp driver which was a simple low side driver for the lamps.  (I was actually expecting it to be a lamp matrix, but it turns out there is a wire for each controlled lamp).  Those two connectors will go to the interface board, and I will use six incandescent wing boards to give me the same functionality.  Next up are the two switch matrices (one for the cabinet and one for the playfield).  I was very surprised there were actually two separate switch matrices, but each his own.  For that, I’m going to add switch matrix support to the OPP firmware, so that will take up another four wing positions.  (The firmware will support up to 8×8 switch matrices.)  In Dolly, the cabinet is a 2×8 matrix, and the playfield is a 5×8 switch matrix.  Next is the solenoid driver board.   The board supports 20 solenoids, but the flippers are simply enabled using a relay.  The Bally interface board will support enabling and disabling flippers instead of grounding the flippers through the flipper buttons.  While Dolly only uses about 12 of the solenoids, I added the extra connectors, so the board could be used for other Bally machines with more solenoids such as Xenon.  The solenoid board also creates the regulated 12V and 5V for the processor.  Instead of generating those, I’m going to use a PC power supply.  A connector was added so the P4 motherboard connector could be plugged into the Bally interface board to tie the grounds of the PC power supply and the old transformer together.  I will end up adding a Raspberry Pi to drive the LCD monitor, and that should be all I need.

Here is a quick view of the PCB layout.  It was a pain to go through the old Bally schematics, but I needed to understand how all that of it was connected together to minimize the chances of needing to rewire stuff.  The schematics are very understandable after you figure out the notations that they were using at the time.  Some things were not as clear as I hoped, but on the whole, they were very good schematics.


Bally Interface Board

So since this is the first post of the new year, we can talk about numbers from last year.  We were pretty close to hitting 10,000 page views for last year, but alas, we fell 100 hits short.  In the end, there were 9,900 views.  Pretty amazing to me.  I could have added another post right before the end of the year, but that just seemed to me that I was trying to gin up the numbers.  There is really no point to that.

That being said, I’m pretty sure this is going to be the last major year for the OPP blog.  I’m running out of things to discuss, and if I get everything done that I’m planning, there really won’t be any other hardware that needs to be done.  I’ll still be around, but I doubt if I will keep updating the blog as frequently.  As I come up with pinball related stuff, I will blog about it, but beyond that it is going to slow down significantly.  But this year, 2017, the blog entries will come fast and furious.

That’s all for now.