Fitting HM7000 Sound to Bachmann Class 3MT Tank

[Britanniabuilder]

I've just bought a Bachmann Class 3MT Tank with the intention of fitting a Hornby 8-TXS sound decoder with power bank. I've run the loco in with a non-sound decoder stuffed into the smokebox and it runs very nicely. I've already fitted an 8-TXS decoder and power bank to a Hornby DMU and have been very pleased with it, hence this purchase, my first non-Hornby loco - I've always hankered after a BR Standard Tank.

 

The HM7000 kit should be arriving tomorrow but I doubt that there will be room in the smokebox area for a speaker, decoder and power bank. There seems to be plenty of room on the cab floor and in the coal bunker for the speaker and/or power bank, but I can't quite see how it comes apart - can anyone advise?

 

Regards, John

[RedgateModels]

I might have a photo of one in bits, I’ll have a look…..

[RedgateModels]

Sadly this is all I have, its been in bits since 2011 and I only put it back together a couple of years ago 

 

[Britanniabuilder]

Thanks, that gives me some clues!

 

Regards, John

[Britanniabuilder]

I've now installed the 8TXS decoder and smallest speaker in the smokebox, and it sounds very good and runs well. There wasn't quite enough room at the front for the power bank, so I'm currently running with the power bank sitting on top of the coal bunker!

 

Unfortunately I still haven't been able to detach the cab and/or coal bunker - after removing the body from the chassis I have taken out the two screws on the centreline under the cab floor, but there's no sign of movement and I can't see any other screws. Any further ideas would be very welcome.

 

Regards, John

[MG 7305]

A quick search of the offical Bachmann website produced this, it may help.

 

https://Bachmann-spares.co.uk/file/3MT-2-6-2-82000.pdf

[Britanniabuilder]

Thanks for looking, that's the same as the instruction sheet that comes with the loco - it describes removing the body from the chassis, but not dismantling the body.

 

If I can't get into the cab/bunker space I may have to do some surgery at the front end under the decoder socket to make space for the power bank, but I don't really want to do this on a brand new loco unless I have to.

 

The power bank really does seem essential - without it, the slightest power glitch over the points causes the decoder to stop and go through all its start-up sounds.

 

Regards, John

[Covkid]

On 29/03/2023 at 17:02, Britanniabuilder said:

I've just bought a Bachmann Class 3MT Tank with the intention of fitting a Hornby 8-TXS sound decoder with power bank. I've run the loco in with a non-sound decoder stuffed into the smokebox and it runs very nicely. I've already fitted an 8-TXS decoder and power bank to a Hornby DMU and have been very pleased with it, hence this purchase, my first non-Hornby loco - I've always hankered after a BR Standard Tank.

 

The HM7000 kit should be arriving tomorrow but I doubt that there will be room in the smokebox area for a speaker, decoder and power bank. There seems to be plenty of room on the cab floor and in the coal bunker for the speaker and/or power bank, but I can't quite see how it comes apart - can anyone advise?

 

Regards, John

 

 

Watched Sam's video on fitting the 7000 series decoders to various models.  Seems to me that perhaps someone needs to create a dummy decoder sized piece of wood or plastic to see what can be done.  I think Sam posted the dimensions  of the current batch, but I think I read somewhere that Hornby are trying to decrease the size when they have obtained new and more compact electronics

[MikeParkin65]

On 31/03/2023 at 09:32, Britanniabuilder said:

 

 

The power bank really does seem essential - without it, the slightest power glitch over the points causes the decoder to stop and go through all its start-up sounds.

 

Regards, John

Haven’t got one of the latest HM chips but have several of the TTS and my experience of them is that they are exceptionally sensitive to any power interruption - this being expressed by the sound stopping even if the loco continues to move. This much more of an issue than with Loksound or Zimo.  

Edited April 1, 2023 by MikeParkin65
Important missing word!

[Britanniabuilder]

Yes, I have several TTS locos and had the same experience - I had to fit tender pickups to a Hornby Peppercorn A1 to fix the problem after installing TTS. The new HM7000 decoders are the same, but the power bank solves the problem completely. The power bank is actually quite small and will slide into the 3MT smokebox behind the speaker and on top of the decoder, but unfortunately just sticks out by a few mm and prevents the body going back on.

 

I'm still trying to work out how to open up the cab to fit the power bank there - RedgateModels' photo above shows that it's possible, but not how!

 

Regards, John

[Britanniabuilder]

I've now removed the plastic body shell from the metal footplate and side tanks - the plastic facing of the tanks had been lightly glued to the metal tanks underneath, and the screw at the front that was meant to hold the footplate to the smokebox had been omitted. A knife blade between plastic and metal released it. I can now proceed to fit the power bank to the cab floor, and I will probably fit an orange firebox LED light at the same time.

 

Regards, John

[Britanniabuilder]

It's now all back together again, with screws and no glue! I just had to grind out a small notch in the metal cab front to let the wire for the power bank through. In the end I didn't bother with a firebox light, because there seems to be no way of operating the light and coal shoveling sound on a single button, so it's too much trouble to use. The cab fittings are incredibly detailed, with driver's pedestal etc, but there's really no way of seeing them short of dismantling the loco or putting an endoscope through the roof hatch! By the same token the power bank is pretty much invisible.