I built this several years ago but I'm just now getting around to posting about it online.  I have a TON of Lego PBricks / Train Regulators / controllers that use a 9-12V~ transformer.  I don't know about you all but AC adapters and transformers drive me up the wall, especially as a project demands more and more of them.  I decided to find a somewhat beefy transformer and create an enclosure with power jacks for all my of Lego devices (I've done a similar thing in my garage for all of my DC devices such as routers, USB hubs, HDMI splitters etc.).  Maybe it will inspire someone to build a similar project and simplify setting up at conventions or at home.  Towards the end of the video I also give a tip for a much more simple solution for fewer devices and requires no soldering.  If you know of any other Lego devices that used 9-12V~ transformers I'd be interested to find out (I think I got them all?).  Also any constructive criticism on the technical aspects are welcome, I've already thought of a few critiques

Something I just thought of while watching a David Koudys video on YouTube, something like this could be used to keep firmware / programs on RCX bricks instead of leaving batteries in for whenever the "next time" you'll use them will be

 

Although I've been uploading videos to YouTube for well over 10 years I am still very much a newbie.  Still working on lighting, sound, color correction etc. so any constructive criticism is most welcome
 

 

Absolutely nice work!

Well, the "AC" bit is a bit strange in the LEGO world - no clue where that came from - other than "this is TLG proprietary stuff - and you better get your hands off because it will be 'bad'". You know, the bit in Ghost Busters, where Dr. Venkman says: "I am fuzzy at all good/bad things. What do you mean, bad?.

BTW: As they did with their hilarious 10V DC power supply for charging 8878 ... oh my.

All the components you are powering with AC voltage in your video, have a voltage rectifying "circuit" inside. Naturally - as TLG motors and stuff are of the DC variety. They can' run on AC. Example: A 9V train motor is a DC motor, as are all the motors TLG has offered since decades. It means they can simply spin in one direction by applying +some Volts and in the other by reversing that (DC) voltage.

Now, this rectifying "circuit" is in every case you have shown a bridge rectifier (as far as I have taking apart these devices, correct me if I am wrong). These run perfectly well on AC and DC power supplies. Furthermore, as the AC has to be rectified from - well - let's call them unknown sources (yes, there are TLG AC power supplies from the past, but you never know, apparently little folks swallow bulky magnets by the numbers - and they certainly plug whatever fits into the socket ...) to 9V DC. So, there is always a voltage regulator as well on these things that have the 9 - 12 V AC sign on them.

This translates to: Use whatever you see fit to get >above< 9V DC (AC may do it at 8V - sureley at about +10V, DC will do above 2x Si diode voltage drop = 0.6V each = 12V DC. Don't worry about any margins ... 15V DC will work fine. I'd stop it at 18V DC, but that is just for the 8878. The good old stuff will get warm, but not blow out.

All the best,
Thorsten

 

   

Wait wait wait. I simply forgot, and this is not nice at all.

Your power supply is of beautiful design. Nicely soldered, cleanly laid out, very nice and clean enclosure!!!

And: It works. Really cool. I like it very much!

Thanks for the kind words, I take great pride and care with these projects.  I've built dozens of power supplies over the years, the first was filled with different sized batteries in a metal enclosure as a kid.  My first project featuring "magic smoke" .  I have 3 custom built power supplies around my house powering anything that would take a DC power supply and is within reach.  I always end up with 2 or 3 surge protectors full of AC adapters if I don't build them (yes I need 3 wireless routers in my computer room).

From what I've seen older devices are much more likely to use an onboard rectifier / regulator with a simple "wall wart" transformer to power them.  Maybe it was an industry-wide change later in the 90's to move to AC adapters that did their own AC to DC conversion.

I could use DC to power my lego devices but I hate the thought of two diodes doing all the work and the other two sitting there with nothing to do .  I don't know the minimum spec of the diodes Lego used throughout the years but I've never heard of anyone frying anything by using DC power adapters (within reason) either.  I have a bunch of AC transformers from seeking them out over the years in thrift stores so I might as well go with them.

the reason nowadays nearly every device uses dc from the power supply is because now the power supplys are switch mode which means internally they chop the voltage to much higher frequencys to get away with using a smaller transformer and smaller components in general as chips/silicon has gotten chep while copper is getting more and more expensive.