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Acer Iconia A500 GPS Issues – Active Antenna GPS390N

I reported in my last post of what I thought was a heat problem causing the GPS to stop finding any satellites.

Well I opened up my Acer Iconia A500 and find that it is using an Active Antenna. What is that, well it means that the Antenna is external to the GPS chip and contains an Antenna (Aerial) and integral amplifier connected by a coax cable and gold plated miniature connector to the circuit board.

Acer Iconia A500 GPS Antena07

The connector is very small and plugs in to the socket on the main circuit board. The miniature coax cable is stiff and puts a load/ strain on the connector.

I unplugged the connector and measured 3.3 volts on the centre pin. The GPS receiver still works with the Antenna unplugged reducing the signal amplitude bars by at least 50% using the GPS Status program.

I had one incident where I lost all the satellites and tried to find out what may be causing the issue. So I removed the tin screening cover from the GPS receiver and then proceeded to warm up the chip & circuit including the Antenna with a hair dryer at some distance. I observed no failure. So heat was not the issue.

Mechanically the connector may have been partially out. Its so small that it was difficult to tell. I carefully squeezed the 2 socket centre blades together a little. If the connector is plugged in at an angle during assembly it may be possible to open up the contacts just a little.

I replaced the back cover. Beware if you should take yours apart (not recommended) take the Micro SD Card out first! the cover will come of ok but when you try to replace it you will bend the Micro SD card and probably break it like I did! Ouch! Lucky I can’t remember what was on it. A few PDF’s, MP3’s and lucky only a few pictures. AU$7.99 for a new Micro SD card.

Final outcome, well time will tell seems to be working OK now. I did notice that when indoors with a much weaker signal (GPS Status program) that I may have 6 satellites in green then yellow then gray and all of a sudden all would disappear. I would then have to move to a better location and wait around 10-15 seconds then that would all come back at the same time (not like when you turn on GPS and one at a time appears). This may suggest that with a low signal that the chip looses sync and needs a strong signal to re-sync. This would not explain why they all disappeared whilst I was on holiday outside in blue sky.

Acer Iconia A500 Back Removed

Iconia A500 with back removed.

The Active Antenna is on the right hand side. The orange rectangle to the right of the pink barcode label. The gray cable looping onto the gold connector is just above. The GPS receiver is just below the gold connector under the square tin cover.

The Wi-Fi Antenna is just down from the top left corner (looks like the first half of the capital letter ‘W’ just above the barcode. The battery is the big black rectangle.

Oldtimer.

2 Responses to “Acer Iconia A500 GPS Issues – Active Antenna GPS390N”

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  1. Moritz says:

    Please tell more about how you managed to open the device.
    There is a sticker next to the SD-slot, do I have to remove that to find a release mechanism?
    My GPS never worked I suspect the antenna connection is off.

    • oldtimer says:

      Moritz,
      Here is a link that has some information on how to open the case.
      http://www.techrepublic.com/blog/cracking-open/acer-iconia-tab-teardown-easy-to-service-3g-ready/

      Here is a video link.

      Search Google for “acer iconia a500 disassembly” will show a few videos of how to open.

      If the GPS has never worked and it’s a new tablet then take it back under warranty. Also as I have posted before switch it on outside and wait about 20 minutes for the Almanac to update.
      Mine worked even if the Antenna lead was unplugged although the signal was weaker.

      !! If you have a SD card plugged in then remove it 1st so that it does not get damaged.

      You need a thin piece of plastic or metal to slide along the edge until you reach one of the plastic tabs then slight pressure to ease the tab inwards at same time use your fingers to try and hold the gap open until you reach the next tab. Start in one corner or in the centre near the external connector.

      Oldtimer.

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