50g - Differences in production batches

[rprosperi]

(04-14-2021 04:33 PM)nlj Wrote:  

(04-03-2021 08:51 AM)Michael Lopez Wrote:  Does anyone know why the Blue unit doesn't have a serial number?

I don't know, but my blue unit doesn't have serial number on the back either. (It was bought on eBay in September of 2014.) Nor does it recognise the SERIAL command.

I don't believe any of the blue 50g units came with serial number stickers, or at least I don't recall any being reported.

I just checked mine and it does respond to the SERIAL command normally. I can't see how some units may or may not respond, assuming they all use the same f/w version.
Is your 2014 unit updated to ROM v2.15? If so, I think it should respond, I'd say check it again, perhaps it was just a typo or something similar?