GPS Antenna Contacts

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jhovak

Member
Sep 24, 2010
7
7
I’ve been struggling with why my GPS quit seeing any satellites after the 9.4.2.11 update when I realized something looking at Anand’s teardown:

AnandTech - ASUS Eee Pad Transformer Prime Teardown

Perhaps the antenna connections are weak or have become slightly corroded. Based on his teardown the contacts are spring type “pogopins” which mate with the opposite face. With that thought in mind I decided to try and flex the tablet ever so slightly to clean the contacts. The idea being that the slight flex would cause the pins to scrape the contact surface rubbing a clean(er) spot.

Before the 9.4.2.11 update I had the typical poor performance from the GPS, getting locks but losing them on the move. I had given up on it [GPS] until this update which touted GPS improvements. After updating and wiping I tested the GPS again, but could not see even one satellite after letting it sit, more than once, for over an hour with Wi-Fi on and off.

I must stress I strongly suggest you do not try this on your tablet for fear of damaging it. I take no responsibly for damage to anyone’s tablet and am only reporting my actions.

After this procedure I am able to see several birds indoors, albeit with weak SNR. This has me convinced that part of the problem is related to these contacts, and may serve to explain some of the weak Wi-Fi reports. It may also help illustrate why only some users are seeing issues, and perhaps why some of the returns are functioning better. These contacts may be more robust in some units or possibly be able to be rectified via service.

I do understand there are other factors related to both the GPS and Wi-Fi, but this appears, at least to me, to be part of the bigger picture.

Please note that the amount of flex I’m talking about is next to nothing, enough to see a change in light bleed around the display, I was afraid to go too far.

*Mods, I'm not sure why this post was deleted before, please PM me if there is a problem with this post. I did not include the link.*
 

motocamp

Member
Sep 5, 2006
7
0
Hi jhovak,

that sounds very interesting and makes me nervous thinking of manipulating a new device. You are brave!
Do you have some pictures of your action?

Thanks.

Cheers,

René.
 

jhovak

Member
Sep 24, 2010
7
7
e.mote,

Looks like you beat me to this I never saw your post, but that's exactly my thoughts. I was able to torque it a bit to get it working again. That maye be what they are doing to get the RMAs reported to work better, "fixed".

motocamp,

Unfortunately I don't have any pictures of the process, but you wouldn't be able to see much, I only deformed the case/screen very slightly. The problem is you may end up popping other solder joints in the process.
 

yhzhrm

Senior Member
Apr 28, 2011
123
16
Halifax
I’ve been struggling with why my GPS quit seeing any satellites after the 9.4.2.11 update when I realized something looking at Anand’s teardown:

AnandTech - ASUS Eee Pad Transformer Prime Teardown

Perhaps the antenna connections are weak or have become slightly corroded. Based on his teardown the contacts are spring type “pogopins” which mate with the opposite face. With that thought in mind I decided to try and flex the tablet ever so slightly to clean the contacts. The idea being that the slight flex would cause the pins to scrape the contact surface rubbing a clean(er) spot.

I agree. Makes perfect sense to me.

Everyone has the same aluminum back, so you would expect the same results across the board (barring weather and atmospheric conditions) for all Primes. There has to be another piece to the puzzle of bad GPS performance when some user's report GPS working and getting locks and other user's reports no GPS active with no satellites seen and no locks.

Thanks e.mote for your explanation of the antena contacts. I think you hit the cause of the GPS problem. Hopefully ASUS saw your post and address this prioblem so it does not occur on their the planned 700 series.

Cheers
 
Last edited:

demandarin

Senior Member
Apr 7, 2010
7,021
2,038
Alexandria, Va
I forwarded all this info to Gary in a pm just recently. including details, link to that thread e.mote posted in and that teardown showing pogo pins. hopefully he will get it soon and pass info to engineers.
 

sdynak

Senior Member
Jun 16, 2010
95
11
Screenshot_2012-01-25-16-06-02.jpg

pardon my lack of GPS knowledge but what is considered good or bad when comparing GPS in general? This is my prime outside earlier but there were fluctuations
 

slybarman

Senior Member
Dec 24, 2010
777
141
I am a bit more skeptical about the hardware pins as a sole cause. Reason:

I had pretty decent GPS performance until this last update which totally killed my GPS performance. This suggests to me that there is a firmware/driver type component to at least some people's problems. The same update did correct other people's problems. So perhaps there are some slight differences in the GPS chips that the firmware is not playing nice with or accounting for?
 

redpoint13

Senior Member
Jan 23, 2012
61
3
I can confirm this at least partially works. I tried to drive home using GPS test the other day from work and could hardly get a lock especially at high speeds. I saw this and did a number of squeezes aroung the area of the GPS connector and had a significant change.

Drove home with GPS test today and I hardly ever saw it not locked, even going at 70mph, though it would go between 2 and 8 locked sats or so. Halfway through the drive I opened google maps. It took 10-15 seconds to lock, but then I watched my blue arrow follow the road exactly almost the entire way home. It only lost lock when I was stopped under an overpass at a stop light.

To be clear the signal strength is not that of my phone, but at least it's working now.
 
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demandarin

Senior Member
Apr 7, 2010
7,021
2,038
Alexandria, Va
Have you seen the new evidence found? It was found out that Original Transformer actually uses the soldered type connection E.mote described. I was gonna start a thread but no use as this one is perfect for the new info.

FIRST here is the quote n pics from e.mote of the current Prime type of connection

From looking at the Prime teardown, your wifi loss may be due to a loose connection. Instead of running a pigtail directly from the chip lead-out to the antenna, the Prime uses spring-loaded pogo pins (1st pic) as intermediate connectors.

Second pic shows the pogo pins for the main wifi and GPS antennae. The spring-loaded pins are pressed against the copper pads of the respective antenna (3rd pic). Suffice it to say, this isn't the most secure way to connect the antennae.

Aside from possible broken or intermittent connection, it also looks like a high-loss connection, and could contribute to attenuated signal reception. My guess is that this may be the main culprit of wifi/GPS woes, with the metal shell being a contributing factor.

The 4th pic below is a U.FL connector that's normally used for antenna pigtails. The lip has an outer overhang for a secure connection.

My guess is that the tablet was bumped and something shifted a bit, breaking the antenna connection.

This is FYI only, as the unit isn't user-serviceable. It does look like a simple fix, but you'd have to open the unit. Edit: You can try smacking the top edge of the tablet a few times and see if it will jar back into place. Worth a try.


Pogo pins used as intermediate connectors for wifi & GPS antennae
168ed06.jpg


The two pogo pins for main wifi and GPS. The spring-loaded heads are pressed against the antennae's pads to make the connection.
1i1gzm.jpg


The main wifi & GPS antenna, with copper pads to connect to the pins
2jb1qic.jpg


U.FL connector, normally used for antenna connection
35mh3ja.jpg

NOW here is the Original Prime teardown and type of connection


http://m.techrepublic.com/photos/cr...-transformer-tf101/6270147?seq=53#photo-frame

OG Transformer teardown pix

6270161-620-413.jpg

6270165-620-413.jpg

NOW HERE IS THE KICKER
that GPS/Wifi connection looks like a soldered wire and not pogo pin to me!

6270186-620-414.jpg


6270197-620-414.jpg

6270198-620-414.jpg

6270199-620-414.jpg

6270191-620-413.jpg


WHO said copy n paste n select text doesn't work well on the Prime? Lol I did this all from the Prime itself from various threads. ;)
 
Last edited:

opentoe

Senior Member
Dec 5, 2011
374
36
Damn, I thought they used pogopins for just the GPS. Now I just found out they use them for the Wifi too! OUCH! Bad idea. A soldered wire would have been %100 much better, but I'm so afraid now to return my tablet to Asus from hearing the horror stories.
 

demandarin

Senior Member
Apr 7, 2010
7,021
2,038
Alexandria, Va
Just got PM a lil while ago from Gary n response to the thread n possible pogo pin issue. He said this is something the Engineers are looking very closely at on units being returned to be looked at or repaired. SO things are moving right along. FOUND OUT ALSO my serial number that starts with BCOKA is actually from an early batch that I guess had the older hardware. Engineer or Service person supposed to call within next 48hrs. They are going down the list of people that Gary got serial number, email, and phone number info from. I guess it must be a big list...lmao
SO if I do have to send it in, then they will be adding the new hardware it and hopefully changing those pogo pin connections to soldered ones..lol
Ill know more details once I get their phone call. If I do have to send in, I hope they don't wipe everything as I have around 150-200 apps n games. Things customized n all that. Ill take the new hardware though n hopefully won't go thru the horror stories I've been hearing about on returns. OR ill like it better if they just sent me a brand new tablet with the latest n greatest hardware changes on it then I send mines to them. So it'll give me time to transfer things to new device if need be.

I HAVE AN APP on my Ipad called applist that will list every app you have installed and allow you to email the list to yourself. Does android have anything like this?
 

racerex

Senior Member
Dec 29, 2011
97
14
Wow. I think we can all agree that Asus dropped the ball in so many areas with the TF201. Who the hell wants to put up with this nonsense???
If only Motorola would build a tablet with a docking clamshell keyboard they could probably take 80% of would be Transformer customers. I'd be first in line.
 

gogol

Senior Member
May 20, 2005
3,735
216
But what could be the reason ASUS changed to use this pogo pin?

Weight? Cost? ... Sabotage? ... I simly dont understand the engineering thought of it.
 

demandarin

Senior Member
Apr 7, 2010
7,021
2,038
Alexandria, Va
Wow. I think we can all agree that Asus dropped the ball in so many areas with the TF201. Who the hell wants to put up with this nonsense???
If only Motorola would build a tablet with a docking clamshell keyboard they could probably take 80% of would be Transformer customers. I'd be first in line.

It would take alot more than that for Motorola to come up n take Asus customers. The xoom, first HC tablet, was a complete flop. Plus Motorola known for locking their systems down, at least initially. MOTOROLA IS NOT too popular of a brand these days, at least tablet wise.
 

dagrim1

Senior Member
Sep 1, 2008
1,710
369
Just got PM a lil while ago from Gary n response to the thread n possible pogo pin issue. He said this is something the Engineers are looking very closely at on units being returned to be looked at or repaired. SO things are moving right along. FOUND OUT ALSO my serial number that starts with BCOKA is actually from an early batch that I guess had the older hardware. Engineer or Service person supposed to call within next 48hrs. They are going down the list of people that Gary got serial number, email, and phone number info from. I guess it must be a big list...lmao
SO if I do have to send it in, then they will be adding the new hardware it and hopefully changing those pogo pin connections to soldered ones..lol
Ill know more details once I get their phone call. If I do have to send in, I hope they don't wipe everything as I have around 150-200 apps n games. Things customized n all that. Ill take the new hardware though n hopefully won't go thru the horror stories I've been hearing about on returns. OR ill like it better if they just sent me a brand new tablet with the latest n greatest hardware changes on it then I send mines to them. So it'll give me time to transfer things to new device if need be.

I HAVE AN APP on my Ipad called applist that will list every app you have installed and allow you to email the list to yourself. Does android have anything like this?

Good to know BCOKA is from an older batch, have such a unit as well and very crappy GPS and also suffer from mediocre wifi combined with bluetooth degradation.

Also contacted Gary and will keep an eye out for any developments (live in EUrope though).
 

racerex

Senior Member
Dec 29, 2011
97
14
The majority of Prime users don't root or flash their tablets. Maybe the majority on this site but not the majority of the total users. So I doubt that will dictate the winners in this market.
Secondly, you can't debate that Motorola's hardware prowess is vastly superior to Asus. And definitely good enough not to pull these bone head mistakes that Asus keeps rolling out one after another.
The Xoom wasn't the sexiest by any means but it was solid as a rock functionality wise. Now with the Xyboard and their follow on products improving in the looks department I really do think they could take would-be Transformer customers if they would just offer a keyboard dock.
And if you're wondering the reason I'm not getting a Galaxy tablet, the reason is because their RF electronic know-how is not too much better that Asus's. I gotta say though that at least Samsung had the intelligence not to seal their RF electronics in a Faraday cage. LOL.
 

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  • 5
    I’ve been struggling with why my GPS quit seeing any satellites after the 9.4.2.11 update when I realized something looking at Anand’s teardown:

    AnandTech - ASUS Eee Pad Transformer Prime Teardown

    Perhaps the antenna connections are weak or have become slightly corroded. Based on his teardown the contacts are spring type “pogopins” which mate with the opposite face. With that thought in mind I decided to try and flex the tablet ever so slightly to clean the contacts. The idea being that the slight flex would cause the pins to scrape the contact surface rubbing a clean(er) spot.

    Before the 9.4.2.11 update I had the typical poor performance from the GPS, getting locks but losing them on the move. I had given up on it [GPS] until this update which touted GPS improvements. After updating and wiping I tested the GPS again, but could not see even one satellite after letting it sit, more than once, for over an hour with Wi-Fi on and off.

    I must stress I strongly suggest you do not try this on your tablet for fear of damaging it. I take no responsibly for damage to anyone’s tablet and am only reporting my actions.

    After this procedure I am able to see several birds indoors, albeit with weak SNR. This has me convinced that part of the problem is related to these contacts, and may serve to explain some of the weak Wi-Fi reports. It may also help illustrate why only some users are seeing issues, and perhaps why some of the returns are functioning better. These contacts may be more robust in some units or possibly be able to be rectified via service.

    I do understand there are other factors related to both the GPS and Wi-Fi, but this appears, at least to me, to be part of the bigger picture.

    Please note that the amount of flex I’m talking about is next to nothing, enough to see a change in light bleed around the display, I was afraid to go too far.

    *Mods, I'm not sure why this post was deleted before, please PM me if there is a problem with this post. I did not include the link.*
    3
    No joke, I'm going to try the "squeeze" method. Just so I'm clear, the antennas are on the power button side (left side looking at face)?

    January 26, 2011
    AsusTEK
    Taiwan

    In response to numerous complaints regarding Wi-Fi performance with the newly introduced Transformer Prime, Asus is providing existing customers with a fix. All newly sold devices will have the fix included in the box at shipping. By simply applying the fix over the Wi-Fi antenna connection on the edge of the Transformer Prime, customers will see an immediate benefit. As always, Asus is constantly stiving to come up with new ways of improving the customer experience.

    images
    2
    http://xdaforums.com/showpost.php?p=21489600&postcount=10

    You can bypass the pogo pins by connecting a pigtail to the UF.L connector at the chip leadouts, then solder the other end to the antennae's copper pads. It should improve reception.
    2
    Have you seen the new evidence found? It was found out that Original Transformer actually uses the soldered type connection E.mote described. I was gonna start a thread but no use as this one is perfect for the new info.

    FIRST here is the quote n pics from e.mote of the current Prime type of connection

    From looking at the Prime teardown, your wifi loss may be due to a loose connection. Instead of running a pigtail directly from the chip lead-out to the antenna, the Prime uses spring-loaded pogo pins (1st pic) as intermediate connectors.

    Second pic shows the pogo pins for the main wifi and GPS antennae. The spring-loaded pins are pressed against the copper pads of the respective antenna (3rd pic). Suffice it to say, this isn't the most secure way to connect the antennae.

    Aside from possible broken or intermittent connection, it also looks like a high-loss connection, and could contribute to attenuated signal reception. My guess is that this may be the main culprit of wifi/GPS woes, with the metal shell being a contributing factor.

    The 4th pic below is a U.FL connector that's normally used for antenna pigtails. The lip has an outer overhang for a secure connection.

    My guess is that the tablet was bumped and something shifted a bit, breaking the antenna connection.

    This is FYI only, as the unit isn't user-serviceable. It does look like a simple fix, but you'd have to open the unit. Edit: You can try smacking the top edge of the tablet a few times and see if it will jar back into place. Worth a try.


    Pogo pins used as intermediate connectors for wifi & GPS antennae
    168ed06.jpg


    The two pogo pins for main wifi and GPS. The spring-loaded heads are pressed against the antennae's pads to make the connection.
    1i1gzm.jpg


    The main wifi & GPS antenna, with copper pads to connect to the pins
    2jb1qic.jpg


    U.FL connector, normally used for antenna connection
    35mh3ja.jpg

    NOW here is the Original Prime teardown and type of connection


    http://m.techrepublic.com/photos/cr...-transformer-tf101/6270147?seq=53#photo-frame

    OG Transformer teardown pix

    6270161-620-413.jpg

    6270165-620-413.jpg

    NOW HERE IS THE KICKER
    that GPS/Wifi connection looks like a soldered wire and not pogo pin to me!

    6270186-620-414.jpg


    6270197-620-414.jpg

    6270198-620-414.jpg

    6270199-620-414.jpg

    6270191-620-413.jpg


    WHO said copy n paste n select text doesn't work well on the Prime? Lol I did this all from the Prime itself from various threads. ;)
    2
    LOOOOONG before any of this was known, before tear downs and pogo pins and what not, you can find a post of mine - late December - where I reported I had so so GPS with nearly zero signal seen or locked on, and then I dropped my tablet while running a GPS test - picked it up and low and behold POW satellites and locks for days.

    Ironic how that post might have been the first indicator of connector issues and none of us knew at the time of that post.