Monday, August 17, 2020

Yep, Thought it might Eventually

Yeh, well, a little while back I upgraded the speaker in my HO scale Walthers GP15 loco from an old normal speaker to a modern Sugar Cube type.  It was a success and she sure did sound good after that.  I did note to myself that the 4 axle loco might in future need an upgrade to a Stay Alive because of her short length.


After having another run on the club layout at Zillmere on Friday night, she had the stutters again - the loco would stall out on some points and dodgy track areas. One of the bogies was also having pickup issues in itself too. So yesterday, after my morning coffee, I pulled her apart and checked her out. 

First thing was to make myself a note to solder all the wires to the decoder board as those press fit connections are never the greatest.  I also made a note, that while I was at it, why not go full hog - add a Stay Alive. You can see the little black press fit caps at the left and right hand ends of the decoder as well as in the middle.  They do have a tendancy sometimes to get loose and then the wires make bad electrical contact.  You can also see that the speaker is about half in and half out of the grey mounting box.

First up I pushed the speaker further up so as to free up as much space in the grey box above the rear bogie.  A bit of thick super glue helped keep it there too.


Next I got out some 2.7 volt, 1 farad Super Capacitors and measured them for fit in the grey box - perfect it was, so onwards with the job I said to myself.

Laying them side by side with a small drop of superglue to hold them in place, I then soldered the 4 of them in series to make my "battery". I also got my handy Stay Alive diagram out for reference to make sure I didn't stuff it up.



Now I had some research to do as the Sound Decoder in the loco is an OEM version of a SoundTraxx Econami.  Hours of looking and nothing specific was found.  But of course Marcus Ammann’s website, http://www.members.optusnet.com.au/nswmn/index.htm, was of course extremely helpful and I was able to ascertain one way or another where I should connect the Stay Alive. It was of course AFTER the 4 rectifier diodes that turn the DCC power into DC power for the decoder. 


So the 4 power diodes are along the left side of the decoder board in the photo. I ended up soldering my wires to the top 2 diodes on the right hand side of each of course. Oh, and YES, Scooter, I did test it first with a multi-meter before soldering.  I had chosen wisely and was in the correct place.

It was now time to start assembling the loco and building the Stay Alive into it.

So with the super capacitor block now under the grey box and held in place with a bit of double sided tape, I drilled a few small holes to hold the legs of the components I was using.  Since I had the space, I left them in the air for a bit of extra cooling.  Might not look crash hot, but it will do the job and will last the distance.


The left hand component is the Zener Diode, the middle one is a Resistor and the right hand component is the Diode.  The resistor gets pretty hot initially when the Super Capacitor needs to charge up, as does the Zener Diode.  Once in running mode it all settles down and is not a problem at all.

Next I soldered on some small plugs so that things can be disconnected if required at a later date.  I added one to the decoder to attach to the stay alive and one to the front headlight so that the loco shell can easily be placed elsewhere when working on the loco in the future.

Some Kapton Tape was then used to hold the wires neatly so the shell can be put on easily.


Some testing was then of course performed and all was good - ready to run at Mr Kennedy's tomorrow morning in fact :-)  I think I earned my Bundy/Coke this arvo.



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