Manual Number 9018205 Revision F, April 1, 2021
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SECTION 5 CONFORMANCE
5.1 INSTRUCTIONS FOR CONTINUED AIRWORTHINESS
No periodic scheduled maintenance or calibration is necessary for continued airworthiness of the
CH93 Digital Clock / Dual USB Charging Port.
If the unit fails to perform to specifications, the unit must be removed and serviced by Mid-
Continent Instruments and Avionics or their authorized designee.
If the unit fails to maintain local or UTC time upon power-up, the internal battery must be replaced
per the instructions below.
Type 1 units: Remove unit from service and return to Mid-Continent Instruments and Avionics for
battery replacement.
Type 2 units: Remove unit from the panel and loosen the screw retaining the battery cover door on
the rear of the unit. Rotate the battery door counter-clockwise and carefully remove the battery with
a non-conductive flat blade object on the side with the battery holder notch. Replace with a new
battery of the same type (BR 2032; compliant with UL 1642).
Verify time remains set after a power cycle and return to service.
Refer to Figure 5.1 below for battery replacement.
Remove battery
from this side
Figure 5.1
Battery (coin cell) Removal
(Type 2 units only)
