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Thread: Help! I can't find my clock battery!

  1. #1

    Help! I can't find my clock battery!

    I thought it would be a good idea to check the condition of my AF 4500 EFIS clock battery after finding an electronic caliper in my workshop with corrosive green stuff oozing out of the little coin-shaped battery.

    I consulted the manual and removed the little cover on top of the housing under which the battery is supposedly concealed and was surprised to find nothing resembling a CR1225 battery. This prompted me to remove the internal battery access plate as well and of course this battery was not hard to find as it was glued to the cover. Alas, the location of the clock battery still evades me and I'm not prepared to dismantle the unit any further for fear of putting my grubby fingers where they're not supposed to wander. I did the same with my AF 3400 MFD and it looked just the same - i.e. no clock battery.

    My AF4500 SN is 61402 and was calibrated on 9.28.2010. My MFD SN is 61693 calibrated on 10.20.2011.

    Do you think you can provide some details on how to find and change the clock batteries?

    I'm also interested to know what adhesive you used to glue the internal backup battery to the cover and the procedure used to remove and change it. Is the backup battery customised by AFS with those neat little connectors attached or is it a simple operation for us builders to to purchase the Varta battery and attach the connectors ourselves and reglue it to the cover?

    Last edited by Mounz; 01-12-2014 at 02:33 PM.

  2. #2
    I see Surfboy's solved his clock problem by changing the internal backup battery. Does this mean my units don't have a separate clock battery?

    It would also be nice if you can answer my thread regarding changing the internal battery above

  3. #3
    The AF-4500, AF-3500s, and AF-3400s (s-CPU) units have a rechargeable clock battery that cannot be field serviced. The only battery that can be replaced on a 4500 is the backup battery.

  4. #4
    Thanks for the quick reply Ken but I have a few more questions

    Would you be so kind as to tell me how long we can expect the clock battery to last. Will it last as long as the EFIS?

    How challenging is it for me to change the backup battery when it becomes necessary?

    How do I remove it from the cover?

    What adhesive do I use to attach the new one to the cover?

    Do I need to purchase a new one from AFS that has the connectors attached to the cable or can I order one from Varta and attach the existing cables myself?

    It hurts for us Europeans to pay more in shipping costs than the items are worth and we also need to be able to do our ongoing maintenance ourselves.

    Some information would be nice pertaining to this subject.


    Last edited by Mounz; 01-13-2014 at 03:14 PM.

  5. #5
    The clock battery is soldered to the main board and should last over 10 years. Even with the internal clock battery dead the clock will be reset from the GPS on power up.

    We sell the backup battery already installed on a new rear cover with the connectors.
    Rob Hickman
    Advanced Flight Systems Inc.

  6. #6
    My one did not last more than 4 years

  7. #7
    No i did not change the internal backup battery.
    I just changed the clock battery

  8. #8
    My 3500 had a normal clock battery round flat type and it was not rechargeable.
    My tech says i should change it every 3 years as a precautionary!!

  9. #9
    Just remember to do this afteer changing the battery otherwise you will have issues

    Did you do a "Set Defaults" after installing a new clock battery.

    From the ADMIN Calibration menu:

    23. Administrator Mode ; enter the code 1010 with the knob and press SELECT

    27. Set Clock NVRAM defaults

    You should also reconfigure your Page List items from the normal run screen:

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