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Have a Bachman DCC 70 ton engine, silent at higher speeds but growls at low, was told their may be a CV fix or other

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  • From: west coast
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Have a Bachman DCC 70 ton engine, silent at higher speeds but growls at low, was told their may be a CV fix or other
Posted by rrebell on Thursday, February 11, 2021 2:28 PM

Figured this is a good engine to start with as if I screw it up, no big deal. I fiqure whatever I learn about changes will come in handy when I work on keepers. It runs fine but the sound of the motor bugs me. It starts out growling and then at a fairly slow speed it hums, like a bit less than1/4 thottle, then it growls a bit at 1/4 throttle, a bit before 1/2 spead the growl is gone. I relize this is a cheaper engine which is why I am willing to play with it

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Thursday, February 11, 2021 2:46 PM

 What decoder does it have? It's it's the Bachmann DCC On Board version of the loco - not much you cna do except change the decoder to a better one. THose decoders do not have 'silnet running' high frequency drive so the motor will buzz or hum. 

                                     --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by jjdamnit on Thursday, February 11, 2021 3:18 PM

Hello All,

I too have a Bachmann HO scale GE 70-ton locomotive equipped with a DCC OEM PCB 2-Function decoder (36-552).

This locomotive has been the bane of my existence!

First, the DCC OEM PCB decoder only supports an extremely limited number of CVs.

If you are using DecoderPro and select the Bachmann 4-function decoder (36-550) you are still dealing with the 2-function decoder (36-552).

Setting the CVs in the 4-function pane won't do anything for the non-supported CVs.

DecoderPro cannot add functions to a decoder, it can only access functions built into the decoder.

You cannot add two more cylinders in your flat-four to make it a V-6 just by using the engine codes for a V-6.

I sent this locomotive back to Bachmann for out of warranty service at a cost of $45.00 + shipping to them. They covered the cost of shipping back to me.

After getting this loco back it ran for a day and then reverted to its erratic running.

I stripped this unit down to the gear towers, re-wired and soldered all the connections including slip-fit connections to the DCC PCB decoder.

The reason I kept the OEM PCB decoder is the LED lights are built onto the board.

After all this, it now runs "better" but needs frequent cleaning of the wheel wipers.

Unless you want to go through a complete "wheels up rebuild" if you want to make this loco a reliable switcher, remove the OEM PCB decoder.

Replace it with a TCS KAM-4 LED decoder with "Keep-Alive™" built-in.

This decoder, despite its price, allows you to use LEDs without resistors and has a built-in Energy Storage Device; AKA, "Keep-Alive™" all in a small package.

This decoder also supports many more CVs including advanced motor functions.

Hope this helps.

"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"

  • Member since
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  • From: Western, MA
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Posted by richg1998 on Thursday, February 11, 2021 4:57 PM

Bachmann for some years have had low end Lenz decoders. CV list at thier site.

 

 Replaced my 70 ton about maybe eight years ago with a LokSound micro. Stripped out everything.

 

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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  • From: west coast
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Posted by rrebell on Friday, February 12, 2021 11:17 AM

Found out CV2 to 255 on one discusion and nano oil and just happen to have some. Read somewhere else that if I snip out the parts for European compliance, that can help. Seems some of it is luck of the draw as their engines are very silent, remember getting an occasional lemon back in the day from the likes of Kato even.

  • Member since
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  • From: Reading, PA
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Posted by rrinker on Friday, February 12, 2021 2:16 PM

 It does help to remove the capacitors on the motor, but it's hard to do much to help the low frequency drive.

CV2 to 255? On most decoders that would mean the loco would jump to top speed at the first speed step.

                                                 --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Friday, February 12, 2021 3:21 PM

rrinker

 It does help to remove the capacitors on the motor, but it's hard to do much to help the low frequency drive.

CV2 to 255? On most decoders that would mean the loco would jump to top speed at the first speed step.

                                                 --Randy

 

 

Wonder why they would say that then, proubly someone who didn't know anything like me LOL.

  • Member since
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  • From: west coast
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Posted by rrebell on Friday, February 12, 2021 3:27 PM

Tried Nano oil on trucks and it has smoothed out most noise except at the low end. It runs real slow on the low end, about 5 sec. to the inch but you can hear the gog sound.  Can one oil the motor and if so conducting or non-conducting?

  • Member since
    February 2002
  • From: Reading, PA
  • 30,002 posts
Posted by rrinker on Friday, February 12, 2021 7:48 PM

 A plain light oil like Labelle is best for motors - just a tiny drop on the bearings where the shafts come through the motor case. A VERY tiny drop. Oil getting on the commutator will just burn and cause problems.

 Removing the capacitors will help. Exactly where they are on that model I don't know - Bachmann has located them in multiple palces across different models. Sometimes on the circuit board, sometimes directly on the motor terminals. Some pictures of the inside and they can probably be pointed out.

                                      --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Friday, February 12, 2021 8:57 PM

I think I see them, bright yellow. My DC 70 ton dose not have a noise (like the boddy better so wanted to see if construction was the same).

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