There was a similar discussion elsewhere on the forum that I posted, but this topic is now unique.

I happen to have an 8 pin v4 with a purchased sound file on it. Bottom line I need to use this decoder on this install in a custom build as I can't afford to purchase a 21MTC and the extra for the file again.

My lighting requires me to use AUX 1, 2, 3 and 4 - that was not the orig requirement, but try I must.  It was suggested that one option is to use the 51968 .

What I know:
1. The 51968 manual is in German only, a rough translation suggests that this board has transistors which provide 250mA on each of the AUX3 thru AUX 6 tabs.
2. The 51968 is designed for 21MTC decoders.
3. Amplification is already supplied on the v4 21MTC for AUX 1 thru 4. 
4.On the v4 8pin only AUX1 and 2 are amplified for 250mA, AUX 3 and 4 are not wired nor powered to that value.

What I've done:
Took the MTC connector off the 51968 and hard wired my v4 8pin decoder directly to the tabs where the connector use to sit.  I also ran two wires from the v4 AUX3 and 4 pads to the correct pads on the 51968 (where the connector was removed).  I added resistors to each AUX pad.

I used Lokprogrammer to assign the AUX1 thru AUX4 to respective Functions as LEDs.

What Happens:
I have FOF, FOR, AUX1 and AUX2 lighting but can't get anything out on AUX 3 and 4.  For testing I checked and double checked all my wiring, and then attached the leds from AUX 3/4 to 1/2 to make sure they were wired correctly.

What I need to know:
If the 51968 states it has transistors to power AUX 3 thru 6, why then can I not light an LED. Is this something to do with the v4 8pin AUX3 and 4 pads not actually being usable whether they are connected to a power amplifier or not?
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This is all sorted now, there is no need to amplify the v4 8pin AUX 3 and 4 tabs, they are already 250mA done, the adapter board really is only of us with the 21MTC v4.
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