Problems with Bachmann Class 40

[James Brake]

I’ve been having issues lately with a Bachmann Class 40. I’m unsure of the catalogue number but the TOPS number on the model is 40141. This loco was supplied with a factory-fitted DCC chip. My layout is DC, so the chip was removed on purchase and a blanking plate fitted. The loco ran fine. A couple of years ago I had the model professionally weathered. After that it ran even better until recently. For no apparent reason, the running has become very sporadic. The loco slows down erratically or stalls. It sometimes refuses to restart. My track is clean, there’s good electrical continuity and my other locos all run fine. I’ve cleaned the wheels & pickups. I’ve sparingly lubricated. I’ve replaced the DCC blanking plate. All to no avail. A search on RMWeb found a fellow modeller with similar issues on (I believe) a Class 47. One of the recommendations he received was to solder the six wires that are loosely fitting & secured by plastic tabs to the circuit board. This was done this afternoon and still no improvement. Does anyone have any other ideas as to what might be causing this intermittent running? Any suggestions would be greatly appreciated.

[john new]

Has the magnet lost part of its mag!* Those symptoms occurred on some of my old H-Dublo locos and they need remagnetizing to fix. 

 

* sorry don't know what the correct SI unit is called for the pull from a magent.

[James Brake]

I like the idea of eliminating the circuit board altogether. I’m not sure I’d be able to here as the circuit board appears to be directly linked to the pickups. Furthermore, would bypassing the circuit board not de-activate the directional lighting. You refer to red wires & black wires, but (if you can see from the photo) there are a variety of different colours…. I’m sure the answer is obvious to someone with experience in this kind of thing (ie. not me). Thanks for the suggestions.

[Mike Todd]

I experienced the same problems with my class 40 and fitted additional phosphor bronze pick up wires from the existing bogie bus to the back of the wheels. One bogie was sufficient for smooth running but I will repeat the work on the other …. one day soon !

[andyman7]

This was the version with wire pickups connected to the wheel bearings; subsequent issues have added wiper pickups to the wheels. However, I should point out that my own example (which I had improved the pickups for) developed very poor running and it turned out that the motor had become defective. It was fine once swapped out for a new one. Maybe a one-off, but highlighting in case that is the problem, so before ripping out the circuit board etc I would bench test the motor.

[andyman7]

On 29/07/2022 at 15:48, john new said:

Has the magnet lost part of its mag!* Those symptoms occurred on some of my old H-Dublo locos and they need remagnetizing to fix. 

 

* sorry don't know what the correct SI unit is called for the pull from a magent.

The motor is a sealed Buhler unit. Unlike earlier Triang or HD mechs there is no option to remagnetize - they last a long time but if they fail it's a replacement that's needed.

[john new]

3 hours ago, andyman7 said:

The motor is a sealed Buhler unit. Unlike earlier Triang or HD mechs there is no option to remagnetize - they last a long time but if they fail it's a replacement that's needed.

Thanks for the info.