Re-setting a decoder

[70E]

I purchased a second hand loco this week, got it home and placed it on a rolling road (analogue), it worked fine at all speeds going forward but stuck, stalled then ran at high speed in reverse! Very erratic.

 

I took it apart and found to my surprise that it had been fitted with an 8 pin decoder.

 

Thinking it might be the running gear or mechanism I  looked at the motor, worm, cogs etc fiddled about with them without any change to the erratic running.

 

So out of curiosity I changed the decoder to a Lenz and low and behold all works fine in forward or reverse direction.

 

I don't know what make the 'faulty' decoder is, I am assuming Hornby (although the loco was not factory fitted) .

 

Is there a CV that would reveal the decoder  identity?

 

Is there a common CV to reset the decoder back to 03 which may resolve the erratic running in reverse?

 

Many thanks

 

 

[pauliebanger]

CV 8 for both.

 

Manufacturers 'registration number' is held, read only, in CV8. Read it and look up the number to get the manufacturer.

 

Hard reset is normally CV8 = 8. This resets the factory defaults, including address 3, but does not change the value in CV8, which is fixed.

 

Paul

[RFS]

CV8 gives the manufacturer's name, and CV7 the decoder type.  So CV8=99 will indicate Lenz, and CV7=93 indicates a Standard+ decoder.

 

It may not be that the decoder is faulty, just that it was having difficulty reading the DCC signal.  Often this is due to dirty wheels or track, or inadequate wiring.  Disabling running on DC will help prevent this - turn off bit 2 in CV 29 (set C V29 to a value equal to 4 less than it currently is).