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Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 10:39 am
by swiftbeam
Hi Guys,

I'm getting a Bachmann City class in a few days, but it comes as 21 pin DCC ready.

I have no need of a 21 pin function, a basic 8 pin will do me fine and save £20 in the process.

Can I simply snip the wires from the pick ups and motor and hard wire an 8 pin directly in and bypass the 21 pin wires and board?

Thanks.
Rob.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 10:57 am
by RFS
Not sure how you are going to save £20 by doing this. A Hatton's 21-pin decoder will set you back £15 which is not much more than an 8-pin one. And once you've hardwired the decoder, any failure will mean you have to do the same again.

I'm not familair with this loco but you might also have a space issue, as it's been desgined for a 21-pin decoder that is roughly the same size as the blanking plug - ie no need to worry about a wiring harness.

Alternatively you could purchase a 21-pin to 8-pin conversion board (Bachmann 36-559) but again space might be the issue.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 12:12 pm
by mumbles
Seems a really strange solution? You can get these as well as the bachmann ones mentioned

https://www.dccconcepts.com/product/21- ... er-5-pack/

Or just get a 21pin decoder? I'm all for saving money and finding cheap solutions but some things require money being spent. Do it right or do it ______!

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 12:33 pm
by End2end
There's a lot of ways to cut corners or save cash in this hobby. I don't think this is one of those times though.
If your a bit cash strapped like me, but have an 8 pin, sell it on to fund the purchase of the correct decoder. :)
I only use 8 pin decoders (except for one 6 pin) and mine are mainly the slighty more expensive non sound Lenz decoders and a couple of Bachmann ones.
I've just completed hardwring the 6 pin via a socket into a loco.... BLEEDING NIGHTMARE! :shock: :x
Thanks
End2end

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 12:48 pm
by swiftbeam
I use Zimo only decoders,
8 pin = £20.
21 pin = £37.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 1:12 pm
by RFS
The 36-559 converter will set you back £3.50. Assuming the decoder socket is in the tender there should be enough space.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 1:14 pm
by Mike Parkes
I have a Lenz Standard 8 pin in a Bachmann Dukedog by simply cutting the links on the blanking plug and soldering the wires from the decoder in place.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 1:49 pm
by swiftbeam
Thank you, I will buy the converter and the 8 pin :-)

I simply don't need the functions of a 21 pin, so totally no point in spending the extra money.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 3:38 pm
by Bigmet
swiftbeam wrote:I'm getting a Bachmann City class in a few days, but it comes as 21 pin DCC ready.

I have no need of a 21 pin function, a basic 8 pin will do me fine and save £20 in the process.

Can I simply snip the wires from the pick ups and motor and hard wire an 8 pin directly in and bypass the 21 pin wires and board?

That's the very thing I do on all 21pin equipped steamers that only have the motor to control, no lights. Lost count of how many I have done now, from the Bachmann 3F, C, J11, O4, and V3 (in that last case a Next18 socket) that I own, and 'various' in addition for friends. I often remove 8 pin sockets too where they are provided, because again and again the manufacturers position them ineptly, usually where weight really needs to be placed, and often with poor access to a suitable void for the decoder!

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 16, 2017 4:55 pm
by Free_at_last
On my 21 pin equipped locos I cut the plug off the 8 pin harness and solder to the 21 pin pcb.

Re: Rewiring a 21 pin to 8 pin!

Posted: Sun Dec 17, 2017 5:00 pm
by Suzie
If you really want to be super economy why not use the MX600 (the one with wires) and modify the blanking plug.

Just cut the tracks on the blanking plug that link the pickups, motor, and wheels, and wire the decoder wires to it.

And while you are at it have a word with the locomotive manufacturer to suggest fitting a PluX socket instead...

I too despair at having to pay £37 for a decoder just because manufacturers cannot adopt a better socket format.

Suzie x

Re: Rewiring a 21 pin to 8 pin!

Posted: Sun Dec 17, 2017 8:20 pm
by RAF96
One would think in this day and age there could be an industry standard reliable edge plug connector for decoders, similar to pc memory storage/sim cards.

This socket could be externally accessible to avoid having to partially destroy an expensive model to access the current internal socket.

Rob

Re: Rewiring a 21 pin to 8 pin!

Posted: Fri Dec 22, 2017 5:56 pm
by swiftbeam
The 21-8 pin convertor and Zimo MX600R (plug fitted) all arrived today, and is now living in the tender of the Bachmann City Of London.

Absolutely no problems at all, it all fitted in with ease and performs 100% perfectly, and I saved £15 :-)

This is totally the way I'm going every time when a 21 pin is fitted and I don't need more than the basic functions !

Thank you for your help :-)

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 23, 2017 1:11 pm
by Suzie
RAFHAAA96 wrote:One would think in this day and age there could be an industry standard reliable edge plug connector for decoders, similar to pc memory storage/sim cards.

This socket could be externally accessible to avoid having to partially destroy an expensive model to access the current internal socket.

Rob


Rob

Edge connectors are not quite as reliable as plug and socket connections when a reasonable current is involved, and the PluX socket range defines a maximum size for the decoder allowing for manufacturers to create a small hatch somewhere (roof, tender or underneath in a fuel tank for example) that the decoder is guaranteed to fit in to. The Zimo MX600p12 low cost decoder is already available along with a full range - just needs manufacturers to see the light. The PluX socket is based on an industry standard 0.050" pitch connector.

Suzie x

Re: Rewiring a 21 pin to 8 pin!

Posted: Sat Dec 23, 2017 4:22 pm
by BananaRepublic
Suzie wrote:
RAFHAAA96 wrote:One would think in this day and age there could be an industry standard reliable edge plug connector for decoders, similar to pc memory storage/sim cards.


Edge connectors are not quite as reliable as plug and socket connections when a reasonable current is involved, and the PluX socket range defines a maximum size for the decoder allowing for manufacturers to create a small hatch somewhere (roof, tender or underneath in a fuel tank for example) that the decoder is guaranteed to fit in to.

.....- just needs manufacturers to see the light. The PluX socket is based on an industry standard 0.050" pitch connector.


A push fit edge connector for decoders, similar to SD and SIM cards, would be fantastic, but unfortunately, probably impractical.

The general situation with different socket formats would be much improved if RTR manufacturers supplying the UK market, would follow the NMRA guidance and start to fit PluX sockets in new models, instead of the superseded 8 and 21 pin sockets.
Most continental European RTR manufacturers have already been doing this for a couple of years.