# DECODER in a MAC



## Treeman (Jan 6, 2008)

Has anyone one installed a decoder in a Hartland Mack? Just opened one up and was surprised what simple wiring it had. Or really how it had almost no wiring. No wires exit the motor block except for a tube holding the head light. I wonder where the best place would be for the decoder. It may go in the motor block and make it self contained.


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## Greg Elmassian (Jan 3, 2008)

You have a lot of options, how about a picture of the loco open? 

Do you want sound? Is cost an issue? 

Regards, Greg


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## Treeman (Jan 6, 2008)

It is not getting sound. I was going to use a Digitrax HO decoder. Less than $20


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## Road Foreman (Jan 2, 2008)

Mike, 

On a nother thread they used a Digitrax DH163.. May be they wanted to add lots of lites..


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## Greg Elmassian (Jan 3, 2008)

You would do well to measure the full slip current of the loco, i.e. hold the loco by the coupler and see what the current is at max voltage with the wheels slipping.

Most HO decoders do not have the current sourcing ability to handle a large scale loco.

This will help narrow down the choices.


If you don't care about sound at all, then maybe one of those MRC decoders that Jerry M. found on sale for $10.22 might fill the bill, just don't use the sound.

Regards, Greg


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## Treeman (Jan 6, 2008)

No wiring extends out of the motor block. I was wondering if it would be wise to fit the decoder in the block. Iam looking for a picture.


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## Greg Elmassian (Jan 3, 2008)

Ahh! A challenge! 

You will have to separate the pickups from the motor leads. you need 4 wires to the decoder, 2 track pickup, and 2 motor. Connecting motor to track is instant destruction to DCC decoders, the "cardinal sin" as it were. 

Regards, Greg


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## Treeman (Jan 6, 2008)

Bob, where did you find that other thread.


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## Trains West (Oct 4, 2008)

I would run the wires out of the block to the decoder rather then put the decoder in the block .......

I have used DH123 and DH163 in trolleys before but even a small loco you need to check the draw when under load.....


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## JeffS (Jun 5, 2008)

Mike, 

Bob Brashear alerted me to your post here. My wife Sue and I installed a ZIMO MX64H HO decoder in a Mack (I figure out which wire goes where and Sue does most of the hard work - disassembly, soldering, installing, reassembly, etc.) 

The install is pretty simple, it's almost like the motor block was designed with DCC conversion in mind. Remove the brass rods which go connect the track pickups to the motor tabs. Cut 2 pieces of straight brass rod of the same diameter (I forget what it was) to the same overall length, solder the decoder track wires to them, and put them in place of the original wires. Solder the decoder motor wires to the motor tabs. 

I forget exactly how the light was connected (I think to the motor) but I do remember they were easy to disconnect and attach to the decoder. We wired both the front and rear light wires to the single bulb. I then set a light effect (flashing, strobe, etc.) on the rear light so we can tell which direction the Mack is going(?!). This decoder fit in the bottom of the motor block. 

Heed well what others have posted here about the current draw and HO decoders. We installed a ZIMO MX64 (it has a lower current rating than the MX64H) in a Hartland rail truck. It worked fine on the programming track but would not run on the main track due (we think) to a high start-up current. We replaced it with a MX64H and it runs fine. I don't know if the rail truck and the Mack have identical motors but I suspect they are similar if not identical. 

Given current pricing, I'd consider low to medium end large scale decoders (Digitrax, Lenz,…) in addition to the MX64H. These would probably have to be mounted outside the motor block but there's plenty of room underneath there. 

A couple of disclaimers: (1) we're mostly an LGB family (H-L-W is our #2) and most of our decoders are LGB/Massoth, ZIMO, and ESU. (2) We have successfully used ZIMO MX63/64 and ESU LokPilot HO decoders in LGB single motor block locos and a "flyer". I suspect the Buehler motors have a gentler startup current draw. 

Jeff S.


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## Road Foreman (Jan 2, 2008)

Mike, 

Can not find the thread again, but the person put the DH 163 D decoders in both the Mack rail truck & the Mack switcher.. Said they had no problems with either.. 

BulletBob


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## Treeman (Jan 6, 2008)

Jeff: Looking at the inside of the motor block your coments about the brass rod make a lot of sense. This model has only one light. Thanks for your ideas.


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## JeffS (Jun 5, 2008)

Clarification to my earlier post - our Mack also only has the one light. We hooked the decoder common wire to one wire light and BOTH the decoder front light and rear light wires to the other light wire. Then set the rear light "effect" CV to flashing while leaving the front light steady. So the light is steady when the loco goes forward and flashes when it's in reverse. (But here's the hard question - which end of a Mack is the front?!)

-- Jeff


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## Guest (Oct 24, 2008)

The HO Digitrax decoders are proving to be pretty robust. I am running an old Big Hauler on one. This is one of the 2nd generation units that has fairly low running current. Also a Lionel handcar on another. The Lionel motor has kinda high stall current for the Digitrax, about 3.5 amps, but I put a 2 ohm resistor in series with the motor to limit the stall current to 2 amps at the low voltage that it will see, about 14 volts. Seems to work fine.

- gws


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## Richard Weatherby (Jan 3, 2008)

Photo of Mack (Clear-see thru).
http://www.mylargescale.com/Community/Forums/tabid/56/forumid/14/tpage/1/view/topic/postid/41163/Default.aspx#41562


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## Treeman (Jan 6, 2008)

Jeff: After rereading your post I understand you were talking about the single light. I used a Digitrax HO decoder with 1.5 amp running current 2 amp peak. I drilled a hole thru the top of the motor block and ran the decoder wiring up to the cab area. Instead of changing the brass rod I turned the motor 180 degrees to avoid the wheel pick up power. This required sawing two notches to allow room for the motor connection points. This is the simplest loco that I have ever opened up. It is made simple with snap together parts to keep the cost down. I have to give HLW credit for keeping jobs in the USA.


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