Bachmann 3-Truck Shay Connector Replacement?

[David P]

Hello all,

I have a damaged 8-pin plug on a Bachmann Fn3 3-truck Shay and need to find a suitable replacement as it is not listed in the Bachmann store. Two of the cables have come out of the crimped connections in the plug and cannot be put back.

There are multiple sizes of the flat 8-pin female connector and I wondered if anyone could point me to a source of the correct width (20.69mm) as I already have several smaller 8-pins in the same style.

8 Pin Female Connector Plug Only.jpg (86.85 KiB) Viewed 6266 times

Most sites that list them do not give connector dimensions and the socket is mounted on the PCB in the frame under the water tank (Bachmann Part G824X-PCB02)

Any assistance would be greatly appreciated.

[ge_rik]

Hi David
Looks like a JST XH connector (2.5mm pitch)
https://www.ebay.co.uk/itm/286144742927

Rik

[David P]

Thanks Rik,

Indeed these appear to be the ones - I managed to find a site on AliExpress that included this diagram:

Plug Specs-AliExpress.jpg (150.65 KiB) Viewed 6230 times

Many well meaning persons said the obvious (Google it) but as I already have smaller dimension connectors in this form I needed to establish the dimensions and pitch of the connectors I was purchasing.

Think I have purchased the ones I need - they were found at: https://www.aliexpress.com/item/1005006 ... 1802MS4lMz

And the table is from the "View More" section in the description.

I don't like modifying things if I can avoid it (the Shay had been hacked about electrically as well as damaged physically when I bought it) hence me chasing a connector that will fit the PCB socket.

[ge_rik]

Well done for tracking them down, David. The sheer range of connectors of this type is a potential minefield with tiny variations in design.

Rik

[David P]

Not wrong Rik,

which is why obvious suggestions of "Google it" are not well received by me (if I am literate enough to be on one of these forums do you think I don't know about Google - really!!!!).

As I stated in earlier posts this form of multi pin connector is available in different sizes based on the pitch (distance between the pins).

I have a stock of smaller width 8-pin connectors that wouldn't do the job as the pitch is less than 2.4mm.

Would have saved a lot of effort if Bachmann actually specified the type of connector on the electrical page for the locomotive (rather than just the PCB part number) - and it is disappointing that I have had no reply from Bachmann support over this issue.

IF the plugs I have bought are the correct replacement I will place a post on all of the forums I am on - to save others the time and effort I have had to expend (including reading dumb suggestions from people who haven't fully read a previous post).

Cheers,

[ge_rik]

Hi David
Fingers crossed they are the right ones. Like you, I do wish manufacturers would stick to fairly common or standard items. I remember trying to find a motor with a worm which would mesh with a Bachmann worm wheel. I tried several with no success. I even tried measuring the teeth on the worm wheel and putting the data into an online calculator which was supposed to give me the module and pitch. Even that didn't work. In the end, I removed the motor and worms from another Bachmann loco and they meshed perfectly.

Rik

[David P]

The 3-truck Shay is fixed - the Amazon order arrived after I had completed the repair but 10Pairs JST-XH Connector Kit, XH 2.54mm 8 Pin Header Male and Female Connectors Plug Adapter with Flat Wire Cable 200mm 26AWG Compatible with JST XH (8P) would have done the job - with the added advantage in that the order comes with the same sockets used on the Bachmann PCB and could be used to repair same.

Several other packets of connectors were purchased from AliExpress and whilst all appearing to meet the same specification only this supplier's connector mated correctly with the Shay's PCB socket under the water tank: 10PCS JST XH2.54 XH 2.54mm Wire Cable Connector 2P/3P/4P/5P/6/7/8/9/10/11/12 Pin Pitch Male Female Plug Socket 10/20/30cm Length sold by DTQ Connector Store.

Note that he lists the sockets as Male connectors (in my industry they are classified as Female - connectors with pins are Male).

This is the image of what to order to suit the Bachmann PCB socket with long enough lead length to go from the rear unit up into the coal bunker:

Connector for Bachmann Shay.JPG (80.33 KiB) Viewed 5734 times

I took the opportunity to rewire the decoder and coal bunker connections using smaller form connectors than the original install that used a 10 pin connector more suited to automotive use (smallest that Jaycar could provide).

20241230_134410[1].jpg (2.29 MiB) Viewed 5734 times

The decoder is an ESU 5XL mounted on stand-off posts with a ten pin socket - the 8-wire loom from the rear unit connects to a 10 pin plug to allow additional wires from the front headlight and cab light to connect to the decoder.

(The Shay came as a wreck from the US with no original electricals after a pretty poor attempt at battery power and radio control with no track power connections and completely non-functional as mentioned elsewhere).

Hopefully my posts here will shortcut the effort anyone else needs to take to repair/replace this loom.

I should mention the wood - the unit is sitting on 45mm gauge slots for the wheel flanges on the top (and 45mm slots that fit over straight track underneath) and is the bottom part of a carry case. As written previously I can drive the engine on and off using an LGB re-railer..........

Cheers,

[drewzero1]

I should mention the wood - the unit is sitting on 45mm gauge slots for the wheel flanges on the top (and 45mm slots that fit over straight track underneath) and is the bottom part of a carry case. As written previously I can drive the engine on and off using an LGB re-railer..........

Cheers,

I appreciate you mentioning that... I was checking it out while reading. Gotta save that idea for later.

[Old Man Aaron]

Very well thought-out and executed.

[jbrawn]

David, I really appreciate you documenting the connectors that made a solid connection to the tender of the Backmann 3-Truck Shay. I couldn't tell what gauge wire you purchased with your connectors. It looks to me they come in 26, 24 and 22 AWG.

Since the rear power pickup and rear motor are connected through that connector (in unmodified units) I would think that the 22 gauge (AWG I think) wire would be what you would prefer with a 3 amp rating as opposed to the 26 Gauge wire with a 0.3 amp rating or 24 gauge with about 1 amp.

I don't know, but I'd guess that the 22 gauge version would be more robust in terms of surviving repetitive handling than the 26 gauge cable.

What are our thoughts about the wire gauge?

Many Thanks,

John.

[David P]

Hi John,

I used the 26 gauge wire in the rebuild - purchased from Amazon: search for 10Pairs JST Connector Kit, XH 2.54mm 8 Pin Header Male and Female Connectors Plug Adapter with Flat Wire Cable 200mm 26AWG Compatible with JST XH (8P).

However I don't have an issue with handling as such as the Shay (and my Mallet) travel in a custom built box that allows them to be driven on and off the base using an LGB re-railer (both are battery powered - I don't run track powered locos except when first purchased).

The box is not the greatest piece of carpentry as I don't particularly enjoy woodworking and as my wife says it is not fine furniture you are making:

20241219_113103.jpg (2.74 MiB) Viewed 807 times

This shot shows how it aligns itself on a straight piece of track:

20241219_113111.jpg (2.53 MiB) Viewed 807 times

And how the LGB re-railer aligns with the track slots in the top of the box (all fabrication was done just using an old table-top saw-bench - no router required):

20241219_113233.jpg (3.24 MiB) Viewed 807 times

I did this as the Shay in particular needs three hands to pick up and the Mallet is only slightly less of an issue. Also by doing this components do not get damaged as occurs when you accidentally grab the wrong thing.

This was reinforced for me on Sunday when one of our club members was seen having to vertically lift a Bachmann 4-6-0 out of a nice box he had made followed by the tender - a future recipe for bits getting broken or damaged (as well as then having to connect cables and the tender bar).

I'm building similar boxes for other locos as I acquire them - a small one I built for a live steam Davenport doesn't require drive-on/drive off (despite it having radio control).

[Old Man Aaron]

Hard to beat a roll-on-roll-off setup, I've done the same across my roster.