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Discussion Starter #1
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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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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Discussion Starter #3
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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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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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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Discussion Starter #8
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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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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Discussion Starter #11
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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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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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.
D45FF47E-B562-440D-9F32-41092262A0C8_1568472181088.jpg
342CBD9B-550E-41BE-85AC-996EA03722B0_1568472194037.jpg
 

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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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Discussion Starter #15
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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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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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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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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