System time won't stay set.

I believe that on the Expression 2x (either "Universal" or "Pre-Universal"), there are only soldered-on capacitors to keep the clock time.  I would recommend working with your local ETC Service Center to see about diagnosing those and possibly replacing them.

The Expression 3 console either has these same capacitors, or may have a battery / battery holder, depending on its generation and which SRAM chips are installed on the CPU board.

If I remember correctly (won't be the first time I'm really way off base...)

Somewhere in the expression line (expression 1? 2? 3?) there was a hybrid Dallas (now Maxim) sRAM/Battery combo chip that was use (24 pin dip ~1mm tall block ).  DS1220Y comes to mind...but that may be from a different device I used to service.  It should still be a DSxxxxx. I believe it is an obsolete part now.  The last time I sourced one it was sampled to me by Maxim because Maxim didn't have it as a part anymore. Things may have changed since then..

I've thought about pulling the sRAM out of the package and piggy-backing a battery, but I haven't needed to deal with recently so I haven't tried yet.

If I remember correctly (won't be the first time I'm really way off base...)

Somewhere in the expression line (expression 1? 2? 3?) there was a hybrid Dallas (now Maxim) sRAM/Battery combo chip that was use (24 pin dip ~1mm tall block ).  DS1220Y comes to mind...but that may be from a different device I used to service.  It should still be a DSxxxxx. I believe it is an obsolete part now.  The last time I sourced one it was sampled to me by Maxim because Maxim didn't have it as a part anymore. Things may have changed since then..

I've thought about pulling the sRAM out of the package and piggy-backing a battery, but I haven't needed to deal with recently so I haven't tried yet.