Power troubleshooting on Mesa 3

20 Apr 2021

This article describes how to troubleshoot power issues on the Mesa 3.

Initial Calibration of Charge Indicator

The charge indicator of a battery (removable or internal) needs to be initially calibrated. The battery must be fully charged and may also then need to be fully discharged to calibrate properly. Until calibrated, the unit may appear to not charge to full, and/or may continue to run even when it indicates being empty. Repeat this process if needed.

Flexible Card Retainer

Verify that the flexible card retainer is fully seated and is not preventing the main removable battery from fully seating, as shown in the following images:

Mesa Card Retainer

Mesa 3 Android Not Powering On

If a Mesa 3 Android unit will not turn on, try plugging in a 30W wall charger and a powered USB-C cable simultaneously. If this works, make sure updates are installed. Further details are at the Mesa 3 Android stuck during boot web page.

External Power Source

The Mesa 3 (or dock) requires a 30W or higher power supply with a 12V output to power the tablet and charge the batteries at the same time. An older charger (such as from a Mesa 2) will not work properly with a Mesa 3. For details, see the following web page:

Old charger will not charge newer product model

You can also try testing with a spare charger or from another unit. Please ensure that the external power source meets the requirements detailed at the following web page.

Power Input Requirements and Limits

Electronically Disconnected Batteries

A Mesa 3 unit may not immediately turn on if the battery pack(s) have been electronically disconnected, such as after holding the hardware Power button for over 17 seconds (often referred to as a "Hard Reset").

To recover a unit that is in the electronically disconnected state, make sure the main removable battery pack is inserted properly in the unit, attach a proper 12V 30W or higher power source, then briefly press the hardware Power button.

Over-Discharged Batteries

Details are provided at the following web page.

Mesa 3 Battery Not Present or will not charge to full

Basically, if a Mesa 3 doesn’t turn on, batteries are not appearing to charge, or the unit is not seeing the battery pack(s), then they may be over-discharged. If this happens:

Plug in the unit.
Fully power off the unit by pressing the power key for a few seconds and selecting to Power Off or Shut Down (not Restart). Optionally, the unit can be put in Hibernate (not Sleep).

Caution: Make sure the battery is within a recommended temperature range (about 68°F or 20°C). Batteries will not charge (or might charge slowly) at temperatures below 32°F (0°C) or above 122°F (50°C).

Leave the unit plugged in overnight.

Note: Initially, the system will only slowly trickle charge the severely depleted battery pack(s). Eventually the red light will begin to flash slowly, indicating that the battery has recovered and is beginning to charge normally again.

When the battery reaches at least 40 percent charge capacity, then the unit may finally again respond normally to pressing the Power keypad button. Juniper Systems recommends allowing the unit to continue to charge until full.

To avoid this issue in the future while using the unit daily, leave the unit plugged in overnight and on weekends as recommended. If not using the unit daily, store the unit and batteries properly as instructed in the Mesa 3 manual.

Door Magnet

Make sure the door magnet is not missing or weak, similar to what is described in Mesa 2 will not recognize or charge batteries.

Loose Charging Port

The charging port may be loose or damaged. Test this by charging the battery using a dock, another Mesa 3 unit, or an external battery charger. If your Mesa 3 needs repair, fill out the Repair Order Form.

Replace Battery

The main removable battery may have unbalanced cells or some other condition that prevents it from fully charging, or in some cases from even being detected. Try swapping in a spare battery or borrow from another unit.