DeCrane Aerospace Audio International
MCD-9101-101-x Installation & Operation Manual
Document # 540360, Rev IR, 03/2008
Page 25 of 28
5.0
Instructions for Continued Airworthiness
5.1
Airworthiness Limitations
No
periodic scheduled maintenance or calibration is required for continued
airworthiness of the MCD-9101-101-x. If the unit fails to perform to
specifications, it must be removed and serviced by a qualified service
facility.
5.2
Cleaning Method
5.2.1 If the front panel gets dirty, turn off the power and wipe the panel
with a dry silicon cloth or soft cloth.
5.2.2 As dust tends to accumulate in the CD slot, it should be cleaned on
a regular basis. CDs can become scratched if placed in a dusty CD
slot.
5.3
General Troubleshooting Procedures
•
To verify power to the unit, r28 VDC power is applied to the
proper pins on the unit. Use a voltmeter to verify correct level.
•
Reset by removing power from the unit for at least 1 minute and
reapply power.
•
Recheck all connections to the unit for security. Check all harness runs
for possible pinching. Recheck all pinouts for application accuracy.
•
To check data bus integrity, utilizing a voltmeter, oscilloscope, or other
voltage instrument, verify proper input voltage on the data bus pins.
Typical measurements with no device(s) on bus transmitting are as
follows:
A-to-Ground : 4.0 to 4.5 VDC
B-to-Ground : 0.1 to 1.0 VDC
If any device is transmitting (i.e., holding bus active), then these typical
measurements would be reversed for the A-to-Ground and
B-to-Ground measurements. This troubleshooting tool can help
indicate a data bus lockup.
•
The RS-485 data bus is a bi-directional bus that does not have a ‘bus
controller’. The bus uses a differential digital signal that will transmit
only when commands are entered via switch selection or other system
synchronizing commands. The “A” leg of the bus is HI and the “B” leg
LOW.
