Class 37800

[Dibby4272]

I looking at fitting dcc sound to a Bachmann 37800 were on the circuit board would I wire the speaker wire to.

Many Thanks 

[mkrob]

Unless I'm mistaken,speaker wires or a speaker comes off the decoder board on 8pin decoders.On locos with 21 pin decoders, the speaker is connected to to SP pads of the loco.

This link may explain better.

https://www.rmweb.co.uk/community/index.php?/topic/39968-speaker-wires/

Edited February 20, 2021 by mkrob

[mikeg]

Dibby usually the speaker is soldered to the blue wires from the chip. I have 20+ locos and all are wired to the wires from the chip, the colour of the speaker wires does very but usually blue but I have purple, black and white amongst the locos with sound.

regards Mike 

 

[Dagworth]

On a 21 pin decoder the speaker connections are on pins 9&10 which are the two next to the missing pin. 
 

the speaker connection pads on the loco in the picture are almost certainly the two pads at the bottom right of the 21-8  adapter plate. 
 

Andi

[woodenhead]

5 minutes ago, mkrob said:

Unless I'm mistaken,speaker wires or a speaker comes off the decoder board.

This link may explain better.

https://www.rmweb.co.uk/community/index.php?/topic/39968-speaker-wires/

Not always - my Dapol 50, the speaker is wired to the board, the Next 18 decoder has no wires off it.

 

But for the 37 here is a YouChoos fitting guide which is to the decoder: https://www.youchoos.co.uk/Index-Resource.php?L1=Guides&Item=OOCL37

[Kaput]

That looks like a slightly older design of Class 37 PCB. Probably be safer attaching speakers directly to the decoder in this case.