B class (hardwired example):
The following model came with a V4 decoder already fitted and hardwired. The customer requested a V5 decoder be fitted, along with premium speakers from DCCSound.
The old decoder was removed and a new LokSound 5 decoder fitted.
Twi sugarcube speakers (S-101) specifically designed for the Auscision A & B class were fitted. These were wired in parallel with the decoder.
A class (21-MTC example):
1) Remove the couplers then splay body around underside from chassis and lift off.
2) Just to the left of the decoder pictured below is where a plug and socket resided "WSW". This is removed to provide more room for the decoder. The wires are soldered directly to where the plug mounted to the DC board. Black on the left, red on the right, as pictured.
3) Cut off the SW plug/socket which runs to the fuel tank.Short these two pins with solder, unless you prefer to run the markers always off.
4) Run the two brown speaker wires from the decoder to the two wires which run to the fuel tank.
5) Plug the decoder in to the NMRA 8 pin socket and refit the body.
6) Remove fuel tank from chassis after removing two screws. A cross member must first be removed as it cover one of the two screwheads. Punch out the switch and baffle plate. They are held in place by a small amount of CA glue.
7) Unsolder the switch from the red and black wires.
8) Fit an ESU 16x25mm speaker to inside base of fuel tank, facing up. Fill in top of tank with styrene or leftover material. Fix with CA glue or equivalent.
9) Refit fuel tank, fuel tank cross member, and couplers.
10) Cover over the switch access hole with some PVC tape. This creates an airtight volume over the back of the speaker for better sound.