Randgust 18 ton Climax build

[160pennsy]

Hello Randy,

One of my ongoing projects is your 18 ton Climax kit powered by a stock Kato 11-107 power chassis. The kit I purchased was one of the earlier versions that included some rectangular metal weights to be used along side the boiler as well as a larger cast metal weight that fits in the middle of the chassis centered over the driveshaft. The weight of the Climax resin kit w/cast metal peices, screws, etc + the Kato power chassis comes out to about 1.1 oz. The running tests (only DC for now) pulling rolling stock on a level surface (an oval of Kato Unitrack) using the 11-107 power chassis with A-Line weights stuck on top have shown that I can successfully pull approximately seven 40' Micro Trains cars without wheel slippage if the power chassis + A-Line weight = 1.36 oz. From your website I see that the newer kits come with a cast metal boiler...how much additional weight will the cast metal boiler add?.

http://www.randgust.com/prod01.htm

The final build plan is to use DCC & I've been trying out different ways to mount the decoder by either cutting a rectangular hole in the power chassis between the phosphor bronze pick up strips (similar to what @Jim Starbuck did) or making measurements to carve out a rectangular cavity underneath the roof piece. Currently using a TCS Z2 decoder (which I already had) but have plans to also try out a ZIMO MX621 Sub-Micro or ESU 54683 LokPilot V4.0 Micro which should have smaller package size than the Z2.

[peteski]

Speaking with @nstars last weekend he steered me to a CT Elektronik being the smallest decoder available. Size: 0.27 x 0.24 x 0.07 Inch (6.9 x 6.1 x 1.7 mm ). Looks like Streamlined Backshop states that they have them for sale but none are available at this time. 
 
/http://www.sbs4dcc.com/tutorialstipstricks/ctdcx76zdfdecodermanual.html

[160pennsy]

Speaking with @nstars last weekend he steered me to a CT Elektronik being the smallest decoder available. Size: 0.27 x 0.24 x 0.07 Inch (6.9 x 6.1 x 1.7 mm ). Looks like Streamlined Backshop states that they have them for sale but none are available at this time. 
 
/http://www.sbs4dcc.com/tutorialstipstricks/ctdcx76zdfdecodermanual.html

There is also a ZIMO MX616 Nano Dimensions: .32 x .32 x .088 inches (8 x 8 x 2.4 mm) but SBS said they might become available sometime between now & Dec 2017, so I ordered two tiny DCC decoders that were in stock  - the ZIMO & ESU parts mentioned earlier. I'll post some comparison photos w/the TCS Z2 once they arrive. BTW the link to the CT Elektronik manual you posted is NG! This works better:

http://www.sbs4dcc.com/images/DCX76z_English.pdf

[peteski]

There is also a ZIMO MX616 Nano Dimensions: .32 x .32 x .088 inches (8 x 8 x 2.4 mm) but SBS said they might become available sometime between now & Dec 2017, so I ordered two tiny DCC decoders that were in stock  - the ZIMO & ESU parts mentioned earlier. I'll post some comparison photos w/the TCS Z2 once they arrive. BTW the link to the CT Elektronik manual you posted is NG! This works better:

http://www.sbs4dcc.com/images/DCX76z_English.pdf

I fixed the link.
The Z2 and the new Digitrax DZ126T have a rectangular footprint, while the MX616 and DCX76zD/F are more or less square shape.  ZIMO also has motor control superior to any Digitrax or TCS decoders.

[narrowminded]

I have used the CT decoder in my miniature chassis and it worked well.  I have not found anything smaller.  Purhased from a vendor in GB.  Shipping and all wasn't bad.

[160pennsy]

Hello Randy,
From your website I see that the newer kits come with a cast metal boiler...how much additional weight will the cast metal boiler add?.

http://www.randgust.com/prod01.htm

Randy,

Are the metal boilers still available for the 18 ton Climax kit? Also leaning more towards mounting the decoder underneath the roof and not messing around with removing the stock Kato PC board that holds down the pickup strips. One build consideration with the under roof decoder mount is somehow incorporating micro connectors for the wiring to allow service down the road if required. Is there anything out there smaller than the TCS stuff which is .098" wide by .06" tall by .12" long...or better yet, should I fabricate a custom solution using thin copper tape strips (used in soldering stained glass together) attached to the insides of the side walls & then running vertical up to the roof? Once the Climax kit is assembled and the cab weight is added space becomes a premium inside the shell.

http://www.delphiglass.com/copper-foil-supplies/copper-foil/3-16-copper-lined-foil-1-0-mil?source=froogle&gclid=Cj0KCQjws-LKBRDCARIsAAOTNd4RY3Mo7UiahTkJboDZwnyUpZTops4Lwm2TPHZS3cNB_n8bjrBMVKgaAoi3EALw_wcB

[randgust]

I designed a modified cab body weight that is shorter so that a TCS Z2 would fit above the driveshaft and below the roof.    I was successful with half a dozen custom builds and then TCS 'improved' it as a dual-mode decoder able to run on analog 12V.   After that improvement, it didn't work well at all despite working with TCS tech support.   I even had Lee Weldon take a crack at it and he couldn't get it to work right - it just kept hiccupping at low speed.   TCS swapped it twice under warranty and finally told me my models were 'too small for DCC'.

So good news - if you can find something the size of a TCS Z2, it will fit.   I considered this a decoder glitch, but not being a DCC expert, it was a brick wall.  Bad news is I haven't done a DCC build since.   But I've seen models just as small work reliably.
Z2 dimensions:  0.51" X 0.26" X 0.11" or 12.95mm. X 6.65mm. X 2.79mm.   That fits the model.

As far as for the boiler - once I learned to cast well in metal I made it standard in the kit.   Metal boiler weighs 9.5 gram and resin boiler weighed 1.2, so that was an easy decision.   If you have a resin boiler the metal one is $5 and first class postage.

I took the wires of the decoder down to the circuit board and cut them with an abrasive disk to isolate the motor contacts from the pickups.  Worked well.  Routed the wires right down in front of the motor and under the floor.  That way you could still pop the circuit board out with the decoder soldered on it for testing.

It's hard for me to believe I've been doing this kit now for 11 years, probably have made about as many locomotives as Climax did.  Another major change from the original kit is the absolute recommendation to repower these with a Solarbotics GM15 3v gearhead (now the GM15A).  I put out supplemental instructions ever since I discovered this, and there are several videos out on YouTube (search for 'randgust') of these repowerings.    Gives you prototype performance curve of a top speed around 12-15 mph, unstoppable torque.  That also opens up most of the tender area for wires or a decoder as well.

[peteski]

I designed a modified cab body weight that is shorter so that a TCS Z2 would fit above the driveshaft and below the roof.    I was successful with half a dozen custom builds and then TCS 'improved' it as a dual-mode decoder able to run on analog 12V.   After that improvement, it didn't work well at all despite working with TCS tech support.   I even had Lee Weldon take a crack at it and he couldn't get it to work right - it just kept hiccupping at low speed.   TCS swapped it twice under warranty and finally told me my models were 'too small for DCC'.

So good news - if you can find something the size of a TCS Z2, it will fit.   I considered this a decoder glitch, but not being a DCC expert, it was a brick wall. 

TCS Z2 decoders had a bug in their firmware which was messing with their speed steps (when the 3-step speed table was enabled).  I wonder if that was part of the problem? Supposedly newer decoders have a fix for that.  But nowadays I prefer using ZIMO decoders - they have motor control and their tunable BEMF parameters are superior to either TCS or Digitrax. Unfortunately they do not make a decoder in shaped like a Z2.
But you migth want to try the Digitrax DZ126T (T stands for tiny). It ia very similar in size to the Z2.

[randgust]

If anybody out there wants to mess with that Z2 - it was working when I took it back out, but it hiccupped at minimum speed - almost rhythmically - whether on DCC or DC.  When the decoder was removed it worked perfectly under DC.

If you think you can solve the mystery I'll mail it to you, the only obligation is to tell me what went wrong.

[peteski]

Randy,
I just want to make sure that I  understood this correctly:  Are you stating that there was an earlier version of the Z2 decoder which was DCC-only (not dual-mode) and which worked correctly in your model?  But TSC redesigned the decoder and the current version of that decoder not longer works in your model?

If that is the case then you have already determined the cause of the problem (the new version of the decoder). There probably isn't much that can be done to get the "new" decoder to work with your model.

I'm also surprised that the older Z2 was DCC-only.  I thought that all the decoders, since early DCC days, were dual-mode (it is part of the NMRA DCC specifications).

I mentioend that Digitrax DZ126T is similarly sized to Z2. Also CT Elektronik decoder DCX76zD/F, Size: 0.27 x 0.24 x 0.07 Inch (6.9 x 6.1 x 1.7 mm ), should fit in that loco.