Tag Archives: MobileMapper CX

Internal Batteries in ProMark 3, MobileMapper CX and MobileMapper CE Receivers

If you have ProMark 3, MobileMapper CX or MobileMapper CE receivers…

…sit down, grab a beer and take a deep breath….

We (iGage) believe that the internal battery backup batteries in these receivers are reaching the end-of-life now.

First, it is not the end of the world. We can replace the batteries for $150 for a single receiver or $250 for two receivers. [ Click Here For More Info ]

Okay, take another breath now and I will share the details:

We have gotten complaints that these receivers are taking forever to begin tracking SV’s

We have gotten complaints that these receivers are not detecting the external antenna (see below for additional information)

We have gotten complaints that receivers are loosing the date/time (well actually this has ALWAYS been an issue, but it seems worse now)

I think that the receivers are losing the GPS ephemeris when the main battery is removed from the receiver for more than a minute or two. This has been verified by measuring the voltage on the backup batteries (actually super caps):

Image

The voltage is 3 volts when the batteries are new, on the five receivers that I opened and checked this week, the voltage was 0.4 Volts or less.

We replaced the batteries in a couple of units and sure enough, they track SV’s in a minute or two after having batteries removed for a while.

You can get around the lost ephemeris issue by turning the receivers on 15-minutes before you need to use them and let them acquire SV’s with the internal antenna while you are driving to the job. You can also keep a charged main battery in the receiver and swap them quickly when exchanging.

But there is a danger in not replacing the batteries: they can leak acid which can eat the adjoining traces. Luckily the batteries are not too big, so they don’t leak much.

More on Not Detecting External Antenna

If you are encountering problems with the PM3 or MMCX not detecting the external antenna, remember that the antenna status is not correctly reported until after the receiver tracks enough SV’s to get a position:

AntExternal

So even if an external antenna is plugged in, it will not be reported until AFTER a position is displayed.

If your battery is dead and you have to wait for 5-minutes for the PM3 to track SV’s, then it may appear that the external antenna is faulty. Not so.

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