My MX-850 looped endlessly in test mode - reporting "RAM FAIL" - so I could NOT download to the unit.

MAIN and ENT together didn't work for me (tried it many times) - but I found this (in Google's cache, the original page is no longer available) and it worked for me:

Try this:

1. Take out one Battery
2. Press the LIGHT button.
3. Put battery back.
4. IMMEDIATELY press the MAIN and STOP button until the little guy disappears.
5. Connect Remote to serial cable
6. On the Editor: Click on File>New>10 devices> Partial Download.
7. On Remote: Test Mode appears> Main Page

Now if the Test screen displays the RAM as EMPTY, call the Technical Support department for further assistance.

Now... for steps 6-7, I actually download my download file (from a Windows machine) with no issues. Steps 1-5 got it out of the endless testing looping so that a download was possible.

It is worth documenting that my MX-850 got into this state because of an aborted download. After spending several hours making my Mac able to download to the MX-850 - I was "close" in getting it to work (using KeySpan, SerialClient, on an MacBook Pro running Leopard with Parallels running Win XP)... but the "close" was that it could read firmware, get programming from the unit, but when loading software into the MX-850 it would give the error "unknown protocol [dltr-4]" at 25% (when it usually tests the unit) and at 50%, halting at 50% the download. This seemed frustrating enough... and I was able to go to a natively running Windows and upload/download flawlessly with the same KeySpan (US-19HS) and MX programming cable (I only have one such setup). So I *knew* the issue, solvable or not, was with getting the MX programming software to work on the Mac. Well, I was stubborn and suddenly found myself with a TEST LOOPING MX-850, and wondering if I had to send it in for a factory flash re-do.

I was thrilled to find your note - but it didn't work for me... but it led me to the MAIN-STOP button combo which did work.

I won't be continuing my experiments in getting the Mac/Parallels combo to work. I'm interested if someone gets a solution, but nervous at continuing experiments with the firmware can get FUBAR.