Bachmann K3 motor/Reaction to feedback control

[HOTTODDY]

I'm not sure if this is the correct topic  section, but I have two handheld controllers (Gaugemaster), a "W" and an "HH". There are no issues with the "W" except dowhill overrun on some locos, but not a big issue. However. The "HH, I believe, is a feedback type, which I rescued from a larger control panel. I installed it into a small abs box, with new lead and 5-din plug. The big issue here is that my K3 and a friend's K3 barely move, emitting a  constant squeaking noise. Amplified it would be a scream!. Needless to say It was tested for just a few seconds as I feared a burnout if I continued. This "HH" was tested on a random selection of other locos, both old and new and all work perfectly well as they should, smoothe, quiet, normal. So my question to all you learned folk out there is, why only the K3?

 

I have removed the body to see if it had a chip in it ( a suggestion from the other K3 owner), but the blanking plate is in place where I presume is where the chip would go.( I do NOT do DCC as I grew up with Hornby Dublo and imagination! ) I have no need for all the bells, whistles etc. which I find annoying at  exhibitions.

 

So there we are with this problem which I would like to solve with your help please. Is it the motor/gearbox drive or electronic feedback control issue specific to the K3?

 

Tod

[34theletterbetweenB&D]

I suspect a crude tuned circuit formed by the simple network of three capacitors, a couple of inductors and the motor. There are many Bach steam models with a similar motor and suppression components to that you see on the K3, and in my case it was a Pannier tank chassis which suddenly started 'singing' at a high pitch and maintained constant speed, not responding to DCC commands. Removing the capacitors fixed it.

 

Got over half a dozen of the K3 chassis in service and trouble free in this respect. The soldering of the wires onto the pick up strips was poor on all my 32-277/278 examples, had to remake all the joints to prevent fall apart syndrome. Might want to check that out. Not had this soldering problem on any other Bach product before or since.

 

Second thoughts: there are 'direct' plug in decoders little larger than the blanking plug. They are recognisably different froma blanking plug though, an array of components on view instead of the simple solder track network of the blanking plug. If there is any doubt, take a blanking plug from another loco and substitute, then test again.

[bigherb]

Try it with another loco that you know that works with that controller on the same track if they both move ok then you need to fit a resistor over the pickups.

[HOTTODDY]

I suspect a crude tuned circuit formed by the simple network of three capacitors, a couple of inductors and the motor. There are many Bach steam models with a similar motor and suppression components to that you see on the K3, and in my case it was a Pannier tank chassis which suddenly started 'singing' at a high pitch and maintained constant speed, not responding to DCC commands. Removing the capacitors fixed it.

 

Got over half a dozen of the K3 chassis in service and trouble free in this respect. The soldering of the wires onto the pick up strips was poor on all my 32-277/278 examples, had to remake all the joints to prevent fall apart syndrome. Might want to check that out. Not had this soldering problem on any other Bach product before or since.

 

Second thoughts: there are 'direct' plug in decoders little larger than the blanking plug. They are recognisably different froma blanking plug though, an array of components on view instead of the simple solder track network of the blanking plug. If there is any doubt, take a blanking plug from another loco and substitute, then test again.

After taking advice from you guys and others I decided that I would remove the chip/blank mount completely and rejoin the black and red wires. Naturally it was red to red and black to black, but on initial test it ran the wrong way (reverse polarity!). It was easier to unsolder the wires to the motor and swap them over and now it behaves as it should with both standard and feedback control. So here endeth the K3 saga, which was frustrating, but I hope it may serve  anyone who may experience a similar problem. Thank you for your suggestions, much appreciated.

 

Tod

[Bob M]

After taking advice from you guys and others I decided that I would remove the chip/blank mount completely and rejoin the black and red wires. Naturally it was red to red and black to black, but on initial test it ran the wrong way (reverse polarity!). It was easier to unsolder the wires to the motor and swap them over and now it behaves as it should with both standard and feedback control. So here endeth the K3 saga, which was frustrating, but I hope it may serve  anyone who may experience a similar problem. Thank you for your suggestions, much appreciated.

 

Tod[/quote

 

Having had the same problem with my K3. Surging at lower speeds with Gaugemaster WS but much worse with the Pictroller I took the plunge last night and tried this. It has transformed the performance. Lovely slow smooth running with the Pictroller now.

 

Bob

[Broadway Clive]

I had the same problem some years ago when the K3 first came out, and I also cut the PCB off and reconnected the wires after Bachmann service department had denied there could possibly be any problem. The idiot there told me that feedback controllers were unrealistic anyway "because real trains speed up when going down hill". I ended up corresponding with their MD Mr Hubbard about it but he took the side of his employee so I forwarded copies to Pat Hammond of MREmag and posted an account on there. Again I wasnt believed by many respondents who claimed the PCB couldnt have any effect, and PH just sat on the fence about my correspondence. I never renewed my Bachmann club membership after that and lost a lot of faith in the objectivity of the model railway media.

 

If memory serves me correct the Ivatt 4mt mogul (flying pig) also had to have the pcb removed.

[kevinlms]

I had the same problem some years ago when the K3 first came out, and I also cut the PCB off and reconnected the wires after Bachmann service department had denied there could possibly be any problem. The idiot there told me that feedback controllers were unrealistic anyway "because real trains speed up when going down hill". I ended up corresponding with their MD Mr Hubbard about it but he took the side of his employee so I forwarded copies to Pat Hammond of MREmag and posted an account on there. Again I wasnt believed by many respondents who claimed the PCB couldnt have any effect, and PH just sat on the fence about my correspondence. I never renewed my Bachmann club membership after that and lost a lot of faith in the objectivity of the model railway media.

 

If memory serves me correct the Ivatt 4mt mogul (flying pig) also had to have the pcb removed.

Was there any components on the PCB? Or possibly a dry solder joint?

 

Edit to add.

 

I've certainly came across some weird faults sometimes, not necessarily model railway related, but bizarre none the less. An example, a piece of equipment that gave strange symptoms. I tried everything & eventually tried from a different GPO via an extension lead - bingo. The GPO was faulty!

 

So yes, I do believe your tale of a dodgy PCB.

[Broadway Clive]

Was there any components on the PCB? Or possibly a dry solder joint?

 

Edit to add.

 

I've certainly came across some weird faults sometimes, not necessarily model railway related, but bizarre none the less. An example, a piece of equipment that gave strange symptoms. I tried everything & eventually tried from a different GPO via an extension lead - bingo. The GPO was faulty!

 

So yes, I do believe your tale of a dodgy PCB.

Its not a case of dodgy PCBs, as I also contacted Gaugemaster and they confirmed that they knew of this problem with several new DCC ready locos at that time. I removed all electronic components along with the PCB, so maybe they were the cause. I realised there were no suppressors left then but c'est la vie!