Fitting an ESU 21 pin Sound decoder to my Heljan class 25.

[P.C.M]

I guys, Looking for some help. I have single motored my Heljan 7mm class 25 and want to fit an ESU  v3.5  decoder. I hard wired a harness with 21 pin socket and the loco ran but I had no sound. I soldered the speaker wires to terminals 9 and 10.

 

I have had success with hard wiring an 8 pin ESU decoder to my class 26 so I am wondering if the pins are wrong on the harness if that makes sense. 

 

Cheers Peter.

[tractor_37260]

Hi Peter

Looking at a 21pin diagram - 9+10 appear to be the correct ones. I no longer have any V3.5s but on a V4 the speaker wires come supplied new attached to the bottom 2 solder pads10 +11(opposite) the blank index pin hole.

So try the bottom 2 solder pads on your photo of the decoder and speaker.

 

HTH

Ken

Edited November 22, 2018 by tractor_37260

[P.C.M]

Hi Peter

Looking at a 21pin diagram - 9+10 appear to be the correct ones. I no longer have any V3.5s but on a V4 the speaker wires come supplied new attached to the bottom 2 solder pads10 +11(opposite) the blank index pin hole.

So try the bottom 2 solder pads on your photo of the decoder and speaker.

 

HTH

Ken

Hi Ken, Thanks for that I have managed to plug in a cheap 21 pin non sound decoder and the loco seems to be running ok. I will probably just end up getting an 8 pin V4 and hard wiring it.

 

Cheers Peter.