[time-nuts] Ashtech Z-12 firmware?

[Gregory Maxwell]

I recently picked up a couple non-functional Ashtech Z-12 receivers
with the external frequency input (these appear to PLL an internal
TCXO; I understand there are other models where they replace the TCXO
completely).

I was hoping to use them both better data sources for common view time
transfer with better performance than the GPS L1/CA  that I've been
using; as well as using them for ground truth data for a SDR
semi-codeless CRPA receiver I'm slowly building.

These units were hanging at startup at "Downloading channel". I
determined that they would work a single time if the memory were
cleared (by holding an arrow, right for external up for internal,
during start). Because the internal 3.6v primary cell batteries were
reading about 40mv I took a guess that the low battery was causing
memory corruption across restarts.

New batteries and a bit of soldering later, and they are working
reliably across restarts, locking sats on L1/L2, talking on RS232,
etc. (hurrah).  Hopefully this message in the archives is useful if
someone else encounters similar symptoms.

Before I go further I was wondering if anyone knew of a source for
firmware for these old units?  One of mine is marked "Z-12 700751-6
(b)", unfortunately it seems ashtech has been sold many times, and the
old web/ftp sites have been scattered to the wind.

The nearest I was able to find was this page
http://kb.unavco.org/kb/article/astech-micro-z---firmware,-firmware-release-notes,-firmware-upload-programs-and-how-to-use-them-368.html
 with micro-Z firmware.

[If there is a relevant GNSS nuts list, I'd be glad to hear about it--
my interest is in CVTT but perhaps somewhere else there is a den of
people obsessed with old survey hardware that would prefer these
questions.]