How hot do decoders get?

[DrW]

In the most recent web page for the Con-Cor Aerotrain there was a warning that caught my attention:  " A small Standard function decoder (no sound), will fit inside the Locomotive body shell and should not generate enough heat to damage the body, just make sure the decoder is NOT TOUCHING the inside of the body shell when you replace the body shell."  I have to admit, while I try to keep incandescent light bulbs away from the shell as much as possible, I never thought about the decoder.  I am using Digitrax decoders, and usually, unless it is very critical to put the shell back on, I do not bother to tape them down.  So far, I never had a problem with an overheating decoder (even in the Bachmann Spectrum saddle tank 0-6-0 where even a Z gauge decoder is a tight fit).   Furthermore, in test runs with engines w/o shell I never noticed that the decoder was exceptionally hot; however, these test runs never lasted more than a 10-15 minutes.  Thus, my question: Did anybody have ever problems with overheating by a correctly installed decoder?  (Yes, I know from personal experience that you can fry decoder by incorrect installation.) 

 Thanks for any information

 JW

[Magnum019]

I run Digitrax Decoders and all of them are just luke warm to the touch, I use two sided tape to secure them.........one problem I had when I first started wiring was improperly hooking up my lights.........engine would run for about 10-15 mins.....and shell was hot enough to fry an egg........was  fortunate enough not to have ruined the shell and did save the decoder.......

 

CJH 

[river_eagle]

sound decoders, especially the mini ones can get pretty toasty, but not hot enough to melt the shell, unless something goes very wrong and the magic smoke gets released.

generally the smaller the decoder the hotter it runs, just not much mass to

dissipate heat from.

[jeffrey-wimberly]

generally the smaller the decoder the hotter it runs, just not much mass to

dissipate heat from.

That's where it's handy to have a metal frame to strap it down to. That wat the frame becomes a heat sink.

[jktrains]

A properly size decoder should not get hot, warm maybe, but not hot and definitely not hot enough to melt plastic.  Most heat related issues come from improperly sized resistors used for lighting.  These can get hot if undersized.  If your decoder is getting hot, these something wrong with it or the install.  Or, you can always open things up a little by removing some fans or grills on the body, look some others have done!

[Texas Zepher]

In the old days decoders used to get really hot.  I've seen melted down shells and even had one instance where the decoder was mounted upside down and the power transistors melted their solder and fell out onto the track.  BUT today's technolgy should not get nearly that hot.

One thing to be careful of, is to not use foam double stick tape such that it holds heat in.  I always try to get at least a small air cavity all the way around the decoder where components are mounted. 

[jeffrey-wimberly]

A trick some of the old-timers use is to tape the decoder down to the locos metal frame (properly insulated, of course) so some of the heat is absorbed by the frame.