Odd SPROG problem....?

[Zerogee]

Though I am very happy with my SPROG programmer and would highly recommend it, I have just had a rather weird result from it - just wondering if anyone here can shed any light on this?

Recently I was trying to alter a couple of CVs on a Massoth XLS (a fairly new chip bought in last few months) fitted to an old clamshell-gearbox 2095 whizzy-cranks BoBo. The loco runs great and sounds fantastic with the big Visaton speaker, in fact so good that I needed to turn the sound down to avoid annoying dogs/neighbours/domestic authorities. So, I put the loco on the test rollers connected to the Sprog, fired up Decoder Pro in the time-honoured manner, and then found that though I appeared to be able to PROGRAM CVs (at least the loco was moving to indicate that the programming had taken), I couldn't read them - all attempts to read CVs resulted in an error message of "301 - no locomotive detected".
So, I tried it on the programming track for the Massoth Dimax - no problem at all, I could read and write any CV I put in.
Other locos I tried on the Sprog would read fine, so the problem doesn't seem to be with the Sprog itself - it just won't read that particular decoder.
Anyone got any ideas?

Thanks,
Jon.

 

[ntpntpntp]

Make sure loco wheels are clean, your rollers are clean and sitting properly on the programming track? That's the only thing thats ever caused read failures with my SPROG setup.

Another suggestion could be a problem with current inrush for the sound, but I was under the impression that the XLS doesn't turn on sound when it's being programmed (not 100% sure about that, not having an XLS myself only non-sound XLs). Maybe try turning the sound volume right down or mute it?

 

[muns]

Ensure that you turn the sound off when attempting to read CVs - maybe the SPROG hasn't the umph that the Dimax system when programming/reading to enable the XLS to provide the correct feedback (especially with that speaker).