Address change for a Bachmann GP-40

[poppyz]

         Info needed; I tried changing the address on my Bachmann GP40 ,DCC loco, from a two digit to a four digit and it seems to accept the change,but,it won`t function.However,when I go back to two digit (02) it works.Tried this several times and had same results.
         I am using a "Digitrax Zephyr Xtra" Dcc control system on a program track as per Digitrax instructions. Anyone have advice to give?

[jward]

have you tried ops mode programming?

or putting a 1000 ohm resistor across the programming leads?

[poppyz]

    No I haven't tried OPS mode only because the Digitrax manual said to use Page on a programing track. The 10k resistor wasn't used since it is suggested to use it when the when the new address is not recognized by the programmer.If the system did not recognize the entry then why could it go back to the old address and operate the loco?
     There is not any logic.   

[jward]

the zephyr will often detect the decoder, but not be able to program it. thus, the unprogrammed decoder operates on its previous address. remember, programmong in page mode uses alot less current than track power. the bachmann decoedrs by themselves don't draw enough current for the programming to work, thus the 1k ohm resistor across the programming leads to draw more current.

ops mode programming will often work as well.