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 responses to “02/26/2017 – 24V SMPS with Power Filter

  1. I’m looking at the description of how to build the power filter board on the pinball makers site, and it seems to indicate that some parts are not needed when not using multiple power supplies. I’m using 24V parts and a single 24V switching power supply, so I’m not sure which parts to leave off based on the power filter board assembly instructions: http://pinballmakers.com/wiki/index.php/OPP

    Can you provide some clarification? Thanks!

    • Since you are only using a single power supply, you need the parts in the “Qty / 1 Switcher” column. That was meant to indicate quantity of parts if you are using only 1 switching power supply. (Not the clearest, but that is what I meant). If you aren’t going to turn enable/disable the power supply, you can also get rid of the PCHAN MOSFET. That really depends on your overall plans for your machine. Send me an email if you have any further detailed questions. (Email address is on the bottom of the Pinball Makers, OPP page).

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