Jubilee......unplugged

[captrees]

The tender of my 00 Bachmann Jubilee was sometimes derailing on bends when pulling lots of carriages. It's a good loco, and I decided I'd add a bit of weight to the tender. I unplugged the wires and took the tender to my workbench. Then I flipped the coal out, revealing a good cavity that I could fill with some lead that I had left over from a lead-light window project. All well so far, until I returned the tender to its loco, and found it nigh on impossible to plug the wires back in. The pins and corresponding sockets are tiny, and pushing on the pins will bend the pins. Its impossible to align them up because you simply can't see.



I've unplugged the wires on locos before, but not had that problem. But it appears it might be a Bachmann thing, as those other locos were Hornby. Now I'm not running DCC, I'm an analogue dinosaur, and I don't know what all those wires do. I guess it all makes sense if the unit is chipped for DCC and the chip goes in the tender. So I had the bright idea that the loco might run without being wired to the tender. It didn't.

What next? Am I missing something? Should I try and pull the tender apart and try and see if I can line it all up visually? (that's a long shot.) Or are there gurus out there that can do this? I don't know anyone in this city who might help. Being relatively new at this stuff, I'm hoping someone here may have suitable suggestions to assist my perplexity.

[Roger (RJ)]

Examine the plug and socket carefully (with a magnifying glass?) and make sure you have the plug the right way round to align with the socket.

[Bigmet]

... I don't know what all those wires do. I guess it all makes sense if the unit is chipped for DCC and the chip goes in the tender. So I had the bright idea that the loco might run without being wired to the tender. It didn't..

Two wires from the loco pick ups to the tender decoder socket, two wires from decoder socket to motor. With the plug out, neither pick up is connected to either motor terminal. (You can just whip the plug off and connect the wires, one pick up wire per motor wire: a little work with an ohmmeter will detect which connects to what.)

Alternatively, are there any ladies in your life? Their dextrous fingers will almost certainly manage to reinsert the plug successfully.

[captrees]

Thanks Bigmet. I needed that information. I suspect that I may resort to just joining the wires. The lady in my life was given the task, but failed. These really are tiny connectors, much smaller than the Hornby equivalent. If I could physically 'see' the male end going into the female end then it might be possible to reconnect but a magnifying glass needed. Random attempts will only damage the pins making it impossible to fix.

[Bufferstop]

The tender is a very convenient place for a manufacturer to put the DCC socket but it does require the use of 4 wires. On a loom behind the smokebox door is probably just as fiddly but does avoid the need to disconnect it so often.

[Mountain]

I can see the bent pins in the photo.

[Bigmet]

As a side note, my opinion is that the use of these plug and socket connections on current RTR OO is suboptimal. If the socket were on the loco, then a simple blanking plug would permit the loco to run on DC without the tender, which can be useful when testing a mechanism.

[Ironduke]

I noticed these mangetic pogo-pin connectors the other day. This technology would be perfect for this sort of application.

[captrees]

Absolutely, Ironduke! The same as my Apple Mac uses. I really can't understand why they have to build them so user unfriendly.

[Bigmet]

... I really can't understand why they have to build them so user unfriendly.

All about keeping the price down, UK model railway is a very price sensitive market.

We could have the overall greater level of refinement found in continental European and North American product, it's all available proven technique. But not at the price the average customer is prepared to pay...

[Peterm]

Absolutely, Ironduke! The same as my Apple Mac uses. I really can't understand why they have to build them so user unfriendly.

Yes. My macbook air uses the "magsafe" connection for charging. If these were used with at least one pair of magnets oriented opposite to the others they'd sort out their own polarity. But as Bigmet says, it's down to price.

[captrees]

Aha. We have a result. It was not as we all thought.

I even press-ganged a local computer geek to see if he could reconnect. I was very impressed with his dexterity and his eyesight, but even he failed to reconnect. Thus I drove into the big city and sought out a guru, with a view to acting on Bigmet's advice.

(You can just whip the plug off and connect the wires, one pick up wire per motor wire: a little work with an ohmmeter will detect which connects to what.)

The guru inspected the connections, and was perplexed until it became apparent what had been done. Mr Bachmann had omitted to glue the connector to the board properly, and in pulling out the plug I had taken the entire assembly out. It should be in two pieces, ie, male and female, and both had come away, exposing those pins. The piece that should have been stuck on the board is a sleeve that shortens the pins, protecting them from bending, but has an extremely tight tolerance, making it near impossible to put the pins in in situ, wires and all.

So I went home, stripped the tender, and pulled the sleeve off the plug. Now I had good access to the pins, and with my better half holding a magnifying glass, I managed to reconnect the pins through the sleeve. I put the tender back together, and the plug slipped on, just as it should have done. Phew. The Jubilee now runs. Now that it all works, it only remains to superglue the sleeve to the board so that this can't happen again.



You can see that the plug socket has square holes which guide the pins in easily. I did cheat by reaming out the holes in the sleeve with a needle.

[Ironduke]

ah! A nice big photo makes a difference too. Those connectors often come loose like that if too much heat is applied at solder-time.