Stall current

Decoders use pulse width modulation to control motor speed. The instant you open a throttle, there is full voltage to the motor, and it hasn't had time to start moving yet. This is Stall Current. Semiconductors burn out very fast, and if this initial current is more than the decoder will handle, it will burn out. Measuring stall current involves physically stopping the motor from turning, while at full voltage. Naturally, this must be done fairly quickly so the motor doesn't burn out. Wheels slipping will give a good average maximum current, but stall current is instantaneous current and is always higher.

Heating Heat shrink tubing

I used all the "old methods: lighter, matches and the barrel of the soldiering iron."  I came across this tool and it works great and gives me lots of control on the heat temperature and has four different tips to direct the air flow.  It is actually used for re-working SMD'S on circuit boards but works great for shrink tubing.

Adding DCC and LEDs to Blue Box locos

Les measured 880mA stall current for the blue box and his decoder is rated at 1.3A.  Per the recommended maximum AWG rating the motor wires should be at least #28 not #30.

shrinking heat shrink tubing

I normally use a heat gun, it is like a hair dryer on steroids. you just have to be careful to not melt anything.

I have had problems with the white motor mounts.

I have had many of them loosen up and allow the motor to vibrate against the inside of the body.  The new black motor mounts from the new model Athearns are cheap & readily available from Athearn, & interchange with the old style mounts and use plastic screws for a solid connection. 

Stall current

I agree with the author on how to perform the stall current.  It is a more accurate way of measuring the most current the motor will demand under "normal" operating conditions.  I have said this before that no model locomotive under "normal" conditions ever "stall" the motor to the point of all rotation stopping.  The decoder in fact does use PWM but that is the KEY to overcoming the initial stall state of the motor by applying a short pulse in milliseconds.  I have yet to see a Blue Box motor damage a decoder due to too high amperage at stall (slipping wheels) as long as the decoder is up to the proper capacity.  Most modern decoders can handle 2 amps or more.  Older decoders may be an issue however.  The NCE decoder that was used in the article is a very robust decoder and can handle 2 amps.  Much more info on Pulse Wave Modulation here>   https://dccwiki.com/Pulse_Width_Modulation

Finally

Folks,

Thank you, I've always had someone else do this. Finally I can hold my head high and tackle the job myself.  The Elephant has left the room.

Bob Henry

Rothesay, NB

Canada

White motor mounts.

I have had the same issues, the old clear ones are even more problematic. 

Here are the part numbers from Athearn

ATH84026 ATH84027 the motor mounts and screws (12 mounts and 24 screws)

Les Green, DCC for Blue Box Author

Tuneup your loco before adding a decoder

The decoder installation in this article is excellent, but the blue box Athearn locos need to be "tuned up" before adding the decoder.  See the November 1993 Model Railroader magazine article on a "Quick and easy Athearn diesel tuneup", page 106-107.  I did this process on my Athearn F45 years ago, before DCC.  It made a huge difference.  Once the loco runs well on DC, then you are ready for the decoder, LED lights, Sound, etc. The tuneup only takes a hour or so.

Rob

DCC decoder installation

I use a DC throttle and do not plan to change, but this article does an excellent job of showing what will need to be done if I should change my mind.

adding DCC to Blue Box

Great article, I have a locomotive I picked up for $20, nothing to lose by trying.  My only comment would be the solder; minimum 60/40 or 63/37 if you can find some as this has an even lower melting temperature, but not 50/50 and not lead free solder either.

cheers

Solder type