First you need to set up a programming track. To do that connect a piece of track to the Program A and Program B terminals on the Zephyr. now you have an isolated service mode programming track.
1. Power up the Zephyr.
2. Place the engine with installed decoder on the programming track.
3. Press the PROG button. If the display reads "PAGE" don't press the PROG button any more. This is what you want. If it does not display "PAGE", press the button again and the display will change. Press it again and again until "PAGE" is displayed
4. Press the "CV" button. The display will read P and three numbers after it.
5. Using the numbered buttons, press "29". The display will change to "029"
6. Press the CV button one time. The display will change to "d029"
7. Using the number buttons press 6.
8. Now press the CV-WR button. The display will flicker a few times.
9. Now press the EXIT button. Take the engine off the programming track and place it on a DC powered track. It should now run on DC.
I give you this way because I am noty sure that the early Digitrax decoders for the ER Sharks actually had the CV8 reset function. Setting CV29 to 6 will make it run on DC as that is what the CV8 reset thing does.
BTW, to program any other decoder CV the steps are the same. Just change the 29 part to whatever CV number it is you want to change. really it took a hell of a lot longer to type this then it actually takes to do.
Martin Myers