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Re: DCC Developments & Experimentation

Posted: Mon Mar 23, 2020 7:42 am
by spturner
For installation of the DCX65, I mostly copied from the photos of your installation, as best I could. I cut the busbars, lifted out the motor, clipped off the majority of the plastic supporting the motor leads, and clipped those leads back as short as I dared. I cut pieces of black and red wire from the end of the DCX65 to connect between the front and back pick-ups where I'd cut the busbars and tucked them as far down along either side of the motor as I could make it go before soldering them in place. I then cut the controller wires very short (but probably not short enough) and soldered the grey and orange leads to the cut motor tabs. I then bent them back so I could solder the now very short (but again, probably not short enough!) black and red leads to the front pick-up leads. I threaded the white and yellow wires through to the front to try to connect up the lights, but that didn't work as I'd hoped.

I had to file the edges of the DCX65 board to remove the fiberglass flash so the body shell would fit back on. I also had to cut the front support post from the body shell because there was nowhere for it to go with all of those wires in the way! After all was said and done, the shell fit back on but won't quite lock all the way down because the wires are a bit too long and lift up on the front a bit. Still, it works and looks pretty good unless you're very close. I plan on (eventually) 3D printing an Amtrak GE Genesis body shell for it so I'll probably leave myself a bit of extra room to make it work. Given the refit, I may just give up on the lights.

I'm running all of this on an experimental oval right now, powered by a Digitrax Zephyr Express meant for my Z scale layout. With zero information out there on how to make this work, I used the UP6Z meant for Z scale DCC to cut the voltage down so as to not fry anything. It all seems to work pretty well, so I went ahead and ordered a couple of more DCX65s to convert my entire fleet (the other GNER and a GP8) for DCC running.

Re: DCC Developments & Experimentation

Posted: Mon Mar 23, 2020 10:51 am
by dkightley
That sounds brill! Chipping the 16m power unit first off was very, well done!

And it looks as if you found the same thing as have to be bold on cutting wires short - the shorter the better. I even had one wire come unsoldered at one end when I was soldering the opposite end!! I wasn't quick enough to stop the heat wicking to the other end!

Now you have a loco working, you'll have to try playing with the decoder settings. My test track loop is about 18 in by 12 in, and whilst playing with settings, I set the decoder so if I ran it at 100% throttle and then tripped it to idle, the loco took four complete circuits round the track to come to a stop! I have it set now so it takes about one and a half circuits....which seems to give a reasonable acceleration/deceleration curve! I've also capped the top flat out is totally unrealistic.

I use JMRI with MERG kits to power everything, and the software makes changing things very easy. I run track voltage at approx. 14v and the decoders seem to be quite happy, and the motors don't get hot even after long running

Re: DCC Developments & Experimentation

Posted: Sun May 17, 2020 5:54 pm
by oliverwhorwood
Thanks to Doug for the modification method.
DCC decoder now installed into a 20m motorised chassis. This surgical procedure certainly isn't for the faint hearted, whilst trying to bend the yellow wire (rear light) back on itself it detached from its solder joint on the very small PCB - somehow manged to solder this back on.

The white and yellow wires for lights are ready to go tucked in at the front of the chassis where they will be appended with some SMD size resistors which will go the front and back of the EMU to the 0402 size LEDs (1mm x 0.5mm). Now onto connecting the track up to to the motor driver and arduino mega.

Empty chassis with motor body cut at an angle to fit the PCB:
Motor with terminals shortened:
Fitting the motor and PCB back into the chassis:
Top view with everything back in place, motor wires cut and stripped ready to solder onto buss bars:
All soldering and assembly completed:
Final product with body shell back on:

Re: DCC Developments & Experimentation

Posted: Sun May 17, 2020 6:13 pm
by dkightley
Well done Oliver!!

As you say, fitting a DCC chip is a challenge.....but despite first impressions, there does seem to be room to get one in....provided you're brave on the wiring lengths. I have to admit I was nervous about cutting them too short!

The 16mm chassis is the real challenge!

Re: DCC Developments & Experimentation

Posted: Sun May 17, 2020 8:20 pm
by davidmatthewson
Fantastic work - many thanks for the inspirational pics too!

Re: DCC Developments & Experimentation

Posted: Wed Aug 12, 2020 5:56 pm
by caitlin
I was using DCX77z decoders, but they seem to be discontinued now.
What source are you guys using for the 65 or other similarly small units?
CoastalDCC say that the smallest they have now are 8*8*2.5mm

oh, I belatedly notice is that the best thing for modern use? I wants more traaaiiiinnnnnssss /o\

Re: DCC Developments & Experimentation

Posted: Thu Aug 13, 2020 1:26 am
by dkightley
The DCX65 is the only decoder specifically designed for use with T Gauge's 5v motors (or should I say 3v motors!)...and do seem to be the most reliable supplier of the decoders in the UK.

Read back on page 2 of this thread for a resume of my attempts to obtain decoders before Alan got some in stock. It seems that most UK suppliers are of the mindset that "normal" model trains don't need to have tiny dcc decoders, then why should anyone want any?

When Alan was out of stock and I wanted a few DCX65's, I did order direct from a German shop who supplied very promptly. Can't recall the name, but I might be able to search back through my emails and find them if needed.

And a compatibility note. The wired replacement motors from do not appear to be compatible....they overheat the decoder in a matter of seconds!

Re: DCC Developments & Experimentation

Posted: Thu Apr 22, 2021 11:24 am
by toottoot
Hi T-gaugers, I've been following this thread with interest and I was wondering if anyone has had any success with LEDs with the DCX65, and if so what are you using? I was struggling a bit with the diagram in the DCX65_English.pdf
The diagram on the left appears to reference 100 Ohm and 51 Ohm Resistors at 5V in anti-parallel configuration, and the one on the right is using 100 and 47 Ohm respectively. Are these two different models of DCX65? How do I know which model I have? Are they cautioning not to use the 5V model with T-gauge? Are the resistor choices just an example?