I acquired an old 9v controller recently. It operates normally, but something was rattling around inside when I shook it. I opened it up to find out what it was and found two small metal pieces which appeared to be a broken in half retaining clip or perhaps something else. I can't for the life of me figure out where this goes, as everything seems to be very secure without it. Does anyone know? I don't have much experience with the 9v system. Incidentally, I was surprised how easy it was to open the controller up, just 4 simple screws. The 12v controller is much harder to open. Of course, back then they made them so they did break, so there was no reason to open them up! I was also surprised by a quantity of little bits of black plastic. I discovered it was the insulation flaking off the wire. Never had a problem with the old 12v wires, even ones 30 years older. I guess it's not just bricks and stickers they make cheaper these days. Sorry, rant over!

IMG_20171208_091119014_HDR by jet_flap, on Flickr

IMG_20171208_091559711_HDR by jet_flap, on Flickr

This seems to be the staple that holds the LM317 regulator against the "heatsink". With a broken staple,  your regulator should be disconnected from the heatsink. Depending on how many engines you use for how long time - and keeping in mind that you don't have a functional heatsink - your LM317 might get very hot. According to specification, I think it works up to approx. 90 degrees Celsius.

Edited December 8, 20177 yr by Haddock51

LM317 is very standard though, so you should be able to find a replacement heatsink.

Thank you for the quick response guys! I will have to try to find a replacement. I think I have the placement correct Haddock51, here's a photo to verify and in case anyone references this thread in the future.

IMG_20171208_120603860_HDR by jet_flap, on Flickr

It may be worth putting a small amount of thermal grease/compound on the side of the LM317 that is pressed against the heatsink. Even if the device will operate up to 90C, it certainly won't be happy about constantly being run on the ragged edge, and should last longer the cooler it operates.

EDIT: It probably doesn't run that hot in general use, but it never hurts.

Edited December 8, 20177 yr by Phoxtane

Well, you already have this hole in the metal-part of the LM317. Just drill a hole into the heat-sink at the area that correspond, and attach both parts with a simple screw and a nut. This way hey did it in the old days on many of this Audio/Amplifier Stuff. Should work and last forever

15 hours ago, Phoxtane said:

It probably doesn't run that hot in general use, but it never hurts.

Back in 2013/14 when I tested gradients and various components for the 9V Extreme layout - incl. 9V speed regulators with mounted thermometers on the LM317s - I remember some occasions when temperature passed 70 degrees Celsius after approx. 6 minutes, and I stopped. Then I decided to upgrade to LM350 regulators and outside heatsinks with a thermal resistance of 1.9 K/W.

Don't underestimate heat management and -control when operating trains with multiple 9V engines and keep in mind the correlation between low speed and high temperatures.

Edited December 9, 20177 yr by Haddock51

Agreed with using heat sink compound, although if the FET burns out, they are an easy fix, if you are handy with a soldering iron and access to RS Components or Maplin

I realize people really like sticking with LEGO branded products, is there some reason any train speed regulator wouldn't work, in the event of eventual breakage of the LEGO one?

17 hours ago, fred67 said:

I realize people really like sticking with LEGO branded products, is there some reason any train speed regulator wouldn't work, in the event of eventual breakage of the LEGO one?

Pretty much anything outputting the correct voltage and amperage will work.  HO train power supply maxes at 18V DC.  Remember not to go full throttle with it or add a stopper around the 9V mark on the throttle.