# new decoder in GE 70 ton Bachmann



## graywolf06 (Aug 14, 2019)

I mentioned in a previous thread that I was buying the Bachmann GE 70 ton switcher. After running for awhile I can state that the low speed operation stinks. It doesn't start moving till speed step 7 and at that it is jerky. I tried to adjust CV 2 but found you can't make any changes that the decoder recognizes. I fact it would not operate at all unless CV2 was 0. I opened it up and see that there is quite a bit of room inside. I happen to have a Digitrax SDH166d with speaker attached lying around and I think I can get it all in there. With the engine came a slip of paper stating that if you change the decoder you have to remove capacitors and inductors. I called Bachmann and they couldn't help me identify them. I see there are 3 yellow things attached to the side of the motor. What are they? also since I would remove the existing circuit board to put in the SDH166d would I be removing the items in question. Also there appear to be LED lights attached to the board front and rear if I attached them to the SDH166 would they work directly or do I have to add resistors and what value? I think I can fit the speaker in the cab at an angle and that would be a plus to have sound. HELP


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## CTValleyRR (Jul 26, 2014)

It actually doesn't sound like there is a real decoder in there. You should not have to modify the loco to swap out decoders, nor should a real decoder not allow modification of CV2 -- that's the bread and butter of low speed operations.

Can you post a clear photo of the guys of your loco? Also give us an actual catalog number for the loco.


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## graywolf06 (Aug 14, 2019)

I took some photos of the GE 70 ton switcher by Bachmann model 60613 but can't find out how you add them to a reply.


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## flyboy2610 (Jan 20, 2010)

The Digitrax site says that this decoder has "FX3 outputs are optimized for both LED and incandescent bulb lighting in locomotives."
I'm just guessing, as I don't have the manual, but I would guess that you need to program the decoder for the type of light you have.


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## flyboy2610 (Jan 20, 2010)

graywolf06 said:


> I took some photos of the GE 70 ton switcher by Bachmann model 60613 but can't find out how you add them to a reply.


When posting, go to the 'advanced' posting page, not the quick post at the bottom of the page. Scroll down to additional options and click manage attachments. This will bring up the attachments dialog box. 
Click choose file to upload the pic from your computer.
Click on the pic you want to upload. Then click on the 'upload' button in the lower right corner of the dialog box.
When you have uploaded all the pics you want, click on Submit Reply like you would on a normal post, and your pic will show up in your post. I still haven't been able to make them show up in the middle of a post however.


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## Andreash (Dec 30, 2018)

You can remove the yellow “things” on the motor. I believe it’s for radio interference.


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## graywolf06 (Aug 14, 2019)

here are the pictures


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## graywolf06 (Aug 14, 2019)

It obviously has a simple or poor decoder in it since I am running it with my NCE powercab. All I can do is turn lights on and off, change direction, adjust speed that is it. This was what Bachmann said it was all it could do. You cannot change CV's. I am wondering if the Digitrax decoder puts out the correct voltage to power the LED lights. I was thinking of putting the engine on the track and touching my multimeter set to DC on the circuit to the LEDs with the existing decoder to see what they are being fed voltage wise. What do you all think? Also do you think the SDH166 will be OK?


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## Genetk44 (Feb 26, 2016)

I’m no expert but that seems like an inordinate number of wires coming out of that decoder...like twice as many as needed. I would wire the decoder to the loco as is, without removing the yellow things first to see what happens.


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## wvgca (Jan 21, 2013)

the 'yellow things' are -probably- inductors and they should be removed for DCC decoder usage ... not mandatory though ... they help to reduce electrical interference ..


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## graywolf06 (Aug 14, 2019)

Genetk44 said:


> I’m no expert but that seems like an inordinate number of wires coming out of that decoder...like twice as many as needed. I would wire the decoder to the loco as is, without removing the yellow things first to see what happens.


Only 4 wires on the right side of the digitrax decoder are used for the speaker and a capacitor for the speaker. The 6 other wires are going to be cut off if I install it in the 70 ton switcher. The wires on the left are for the motor, pickups,and lights.


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## flyboy2610 (Jan 20, 2010)

I installed a sound decoder in a Bachmann 4-8-4. I removed the capacitors from the motor. It runs fine.
You seem to have separate red and black wires from each truck, plus the two motor leads. Solder the red wires together, solder the black wires together, then solder the red and black wires from the decoder to the appropriate wires. Solder your motor leads in place and test the locomotive.
I agree with you about using a multi-meter to check the light function output voltage.


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## Andreash (Dec 30, 2018)

There are 9 wires coming out of the decoder, 2 for the motor, 2 for track pickup, 3 for lightning (blue is common), and purple and green for fx effects. That is normal.
The photos below show a Bachmann motor that has the radio interference items removed, and the decoder installed. The engine now runs flawlessly.


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## Andreash (Dec 30, 2018)

I run a digitrax dh126 decoder, and the purple and green wire are not used, as the decoder doesn’t support the fx effects. In engines that have a strobe light, I use a 166
decoder.


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## graywolf06 (Aug 14, 2019)

Ok I clipped the Capacitors off the motor. No discernable difference in operation or sound. I tested the voltage to the front light and it is 2 volts DC. On Monday I will call Digitrax to find out what the voltage output is from the SDH166 is to the lights. If looks good I will go ahead with the operation --hope the patient pull through.


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## Andreash (Dec 30, 2018)

On my Bachmann gp38 install, I replaced the lights with leds. You could hook up your red and black wires from the decoder to track power, turn on the headlight (from your throttle) and measure the voltage output (white and blue) (forward light)...


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## graywolf06 (Aug 14, 2019)

Good idea ---Thanks --sounds like you want me to get the job done this weekend.


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## Andreash (Dec 30, 2018)

Where there’s a will, there’s a way....

I used leds (Evans designs) that are rated at 7 to 19 volts. The output is high from the decoder....

And lastly, if I recall, the motor wire leads were reversed. I had reconfigured cv29, but had headlight issues (run forward, rear light on and vice versa). I think I used cv63 to reconfigure the light, but it didn’t work. The real simply solution was to change the wire leads at the motor (took 2 minutes to resolder, vs looking up the digitrax website on a smartphone (15 minutes of searching)...cheers


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## DonR (Oct 18, 2012)

The typical decoder light output is 12v dc. The blue
wire is common, and you should note when
connecting LEDs, it is PLUS.
You would need resistors for the LEDs.

You can set the CVs on the Bachmann decoder but,
as others have noted, it does not offer the smooth
control most of us want. My brother did set the CVs
for me to enable consisting of my two GE 70 tonners. They
then were good performers. Capable of very smooth
walk speed. I did add weight so they could pull more
cars.

Don


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## dagnarble (Mar 23, 2010)

Go to the TCS website they have installation of decoder in GE70


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## graywolf06 (Aug 14, 2019)

dagnarble said:


> Go to the TCS website they have installation of decoder in GE70


Thanks for the tip. I had tried looking there but didn't look down the list at the Spectrum engines. They have some nice photos of the install but I don't see the point in leaving the old board in place just to have the lights supported. My plan is to eliminate the PCB and modify the weight so it sits where the original decoder or PCB is. I will insulate the weight with Kaplon tape and mount the new Digitrax decoder on top of it. I will eventually add LED lights from Evans into the shell but initially will try out the new setup without lights to see how it works. Thanks again.


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## Andreash (Dec 30, 2018)

Your on the right track removing the board. The advantage of some room, and a clean install will be worth it. Try to keep the leads long, but should a wire come off (from the truck), just resolder. I installed a decoder in a non dcc Bachmann F40 which involved grinding the metal weight, and typically most people wouldn’t try installing in this engine. But I wanted to see if it could be done, and I was up to the challenge ( I posted the install in the dcc section of the forum, as well as some others)...good luck and cheers


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## graywolf06 (Aug 14, 2019)

Well the deed is done. Just finished the install minus the speaker. I ran the loco without the body and the speaker just dragging along behind. It all worked except when I went to button it up the speaker got in the way. Clipped it off and taped up the wires for now. Will look for a tiny speaker. Had to grind the weight down so the decoder didn't go thru the roof. I kept track of how much weight I was removing and was very surprised. The original weight was 28gr and all I removed was 2 gr. The net effect was a gain of 4 gr since the Digitrax was heavier than the original. This switcher is less than half the size of my other diesels and I must give a hand to those of you that work on N scale. I had to resort to tucking in the wires with a wooden coffee stirrer. All in all the engine is super smooth and quite. Digitrax has a chart to set up a dedicated switcher which dials in very slow speeds via CV2,5 &6. Thanks for all the help you all gave me. Paul


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## flyboy2610 (Jan 20, 2010)

Glad you got it done! Now, on to the next one! (And you know there will BE a next one!  )


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## graywolf06 (Aug 14, 2019)

I thought I was finished but today I picked up a ESU 50321 sugarcube style speaker and installed it in the cab on the underside of the roof. Wow it sounds great and the little switcher has a real growl to it since the diesel program in the decoder is for a GP38. The operational difference of the engine is great compared to the stock setup. On to the next one.


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## sid (Mar 26, 2018)

he is addicted now hahahahaha any pics of the install hummmmm ?


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## graywolf06 (Aug 14, 2019)

Some photos if we are lucky. I filed some grooves in the weight to allow for the increased height of the Digitrax decoder. Only lost 2 grams of weight. The other photos show the decoder mounted with the old speaker which turned out to be too big. During operation this morning with the loco towing 5 cars I noticed that the traction is not good as it tried to go up a 2% grade. It just sat there spinning its wheels.


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## flyboy2610 (Jan 20, 2010)

graywolf06 said:


> During operation this morning with the loco towing 5 cars I noticed that the traction is not good as it tried to go up a 2% grade. It just sat there spinning its wheels.


I think that might be asking an awful lot of that little guy! 
If it can move 6 or 7 cars on a level surface, that's probably doing pretty good!


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## graywolf06 (Aug 14, 2019)

Just wanted to see if it could do it since it now has a transplanted GP 38-2 decoder in it. It sounds the part --guess it has more bark than bite. HAHA


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## Kevin B (Jun 28, 2021)

Can anyone advise me how to remove the shell. I've tried several techniques with no success, and wonder if it separates with sheer force.


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## graywolf06 (Aug 14, 2019)

Kevin B said:


> Can anyone advise me how to remove the shell. I've tried several techniques with no success, and wonder if it separates with sheer force.


Not sure if I remember but there are 2 screws coming up thru the fuel tank that need removal. You also might need to spread the shell apart and just insert toothpicks as you spread it to hold it from going back together.


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## Kevin B (Jun 28, 2021)

Thanks. I neglected to say it's N scale. No screws on the belly side (except couplers). I probably need to just pull it off, but....


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## DonR (Oct 18, 2012)

I had 2 DCC Bachmann HO 70 ton switchers. I found that the factory
delivered weight is far too light. I added lead weights in various
areas under the shell. That did the trick. They can now pull like their big brothers.

Don


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