Thanks for the detailed reply, much appreciated. I have to admit up front, I am absolutely not expert at this. I’ve got about 70 locos, some with retailer installed decoders, some factory fitted and a fair few I’ve fitted myself. I’ve tended to go for retailer fitting when the locos are particularmy detailed or expensive, to avoid mishaps where detaching the body can be tricky. With the 66’s, as they’re basic models, I decided to do it myself. For all, they run analogue fine with both the blanking plate in and the decoder in, only on my DCC layout do they fail to run, even though they appear to have programmed fine on eLink. Since posting earlier, I also had a retailer fitted DJ Models Class 71 which I’d not got around to programming. I’ve since programmed this (it has a 21 pin - probably Hatton’s decoder fitted) and although that programmed fine, again, it will not work on my layout, but will work analogue on a separate test track I have. This I assume means the issue must be with the eLink software/unit as opposed to the locos or the decoders. All other previously programmed locos seem ok (have tested 8), it all seems to have gone wrong from loco 66 onwards. Any ideas on rebooting it, updating software etc. etc. As indicated earlier, I’m on version 1.70. Historically eLink has occasionally been temperamental but turning on and off has usually solved. Thanks again.