I dont know if you've remedied your problem but ironically , this just happened to my little Bachman 2 6-0 .. I Finally just reset the decoder setting CV 8 to a value of 8 ...it worked but subsequent attempts to reset the engineg address failed ( I do these settings in a PROGRAM mode on a Digitrax system while the engine is on the main not on a programming track ...this is  a standard practice) yet I did reset my momentum CVs 3 and 4 without any problems. For what it is worth, in general I feel these decoders are not very good.  They have minimal functionality and they tend to be a bit quirky ( as you and I have experienced with the bell episodes ). Bottom line is "you get what you pay for ".

I am reading through your posts and it sound as if you've done everything correct. I am  wondering whose DCC system you have. I have done these mods on Athearn BB engines numerous times without incident . One thing that could be the problem is track power is too high . ...just a thought as you've appeared to do everything else correct . On my Digitrax system, using the AC scale on a meter               (although it is really not an AC source), you should get about 12-14 volts   ...also, I would think the low end Soundtraxx ( Econami ) should  easily handle the .58 amps....for what it is worth ...good luck !

I've waited well over a year now for GP7s handrails. I have two GP7s that need replacements after breakage while painting . Does anyone have a source for these ? Bachmann continues to say they are "out of stock " . Any advice  you have will be appreciated . Thank you !

I wish I had the success others have had with this engine. I now have three, all of which have had or continue to have problems with the belt drive. I have purchased new belts, worm gears and a whole lower assembly and new pins that hold the casings together in trying to get them in better running order. I recently repaired one the of the engines and reassembled the two halves. I tested the motor and the worm gear turned fine. When trying to attach the lower unit, the worm gear would no longer mesh with the spur gear on the axle. I cannot imagine what I have done wrong. I love the looks of these engines and when running, especially with a better decoder, their low speed performance is excellent. I use a tsunami decoder in one of them using F11 braking ...a great feature especially for steam. I recently purchased a WOW steam decoder, but given the problems I am having, I am reluctant to install this decoder in one of these engines. Id love to hear from others who have had these problems ....I've had other Bachmann engines ( K4) which I loved and used extensively but it did use a far different drive system. I'll look forward to hearing form others..Thanks , Rich