sound module and decoder

12/27/2001 sound module and decoder
See below for update with schematic...

I bought a used Märklin loco catalog number 33803 which is a Delta locomotive with a sound module.
The previous owner had it converted to digital, I assume with a 60901 decoder because the old delta decoder was included in a 60901 box.
The chip on the sound module says
MKL 502601 V1.2
9735K1741
When the loco is on the track it makes a diesel idle sound whenever there is current in the track. It does not switch off after a while.

The Function key on the IB makes the sound 'pick up' (or lubrication pump sound?) and switches on the lights. F1 through F4 do not seem to make any difference in anything (but I am not able to judge any acceleration difference in my shortish test track) the IB is set to use Motorola New for this loco.

As the loco speeds up there is NO perceptible change in the sound.

The lights do flicker.

The instruction leaflet suggests that the digital version 37803 allows one to adjust the duration of the advance lubrication sound, starter, 1 or 2 motor sound and sound shutoff after 10 seconds of idle using 4 DIP switches. I do not see these DIP switches so I assume the digital version comes with a slightly better sound module than the Delta ? In addition F1 should switch the sound on and off and F3 should sound the horn. F2 and F4 control the headlamps.

The Delta instructions do however suggest that the motor will make different sounds at different speeds in both digital and analog operation. So this sound module must be capable of that.

So my questions are:
1. Did the Delta version come with a sound decoder inferior to the digital version? - YES
2. Can the 60901 decoder be connected so that I get better functionality from the sound module ? (hey even analogue mode can have the sound off!)
3. Is this a 60901 decoder ? - YES
4. What are the spare leads coiled up in front of the speaker for ? F1 and F2
5. More questions below...

Update 2001-12-28...
Here is the schematic of how it is wired to the decoder.

There are no DIP switches on the sound module so it seems that the sound module with the Delta version is not the same as the one that is installed with the digital version.

So please suggest how I could use the F1 and F2 outputs that are currently not connected so that I can make better use of decoder and sound module.

I assume that I could take the yellow and gray lines and connect them to the lights and not to the sound module at all.
Then perhaps the F1 and F2 outputs could be connected to where the yellow and gray outputs go at present ?
How can I switch the sound off independantly from the lights ?

I suspect that:
- orange supplies current and that forces the idle on all the time
- violet is the ground return
- Gray and yellow cause a slight increase in speed ? so when the lights (F0) are on, you get a speed sound ?

Please send suggestions and ideas to me at v200@mixmox.com

For reference, here is Jürgen Schad's 60901 documentation...

Thanks
Dale