New 9537 - Cannot get GPS signal, I think! - Only solid blue

hanoudi · Occasional Visitor Joined: Mar 03, 2005 Posts: 11

can you please let me know where you got it from?

Vic · Posted: Wed Mar 30, 2005 3:56 pm Post subject:

Off Ebay, supplier in Germany. Look for 'MMCX GPS Antenna'

hanoudi · Occasional Visitor Joined: Mar 03, 2005 Posts: 11

Thank you

tarquin · Occasional Visitor Joined: Feb 24, 2004 Posts: 4

Hi Vic

My Leadtek, over a period of about a week took longer and longer to aquire sat's untill today it gave up. Tried it on an external ant and all was well. So like you suspected the front end block amp. Anyway I removed it and looked around for an eqiv. Found a few in old mobile phones but as they have limited info stamped on them, usually 3 letters its difficult to know what they are. How did you find out the original was a BGA622? Anyway none of them worked infact stopped the first green flash when initially switched on. Even tried a similar one from a polstar front end. You can see that the earth pin is slightly wider than the other three. Could not source small quantities from anywhere so I got my external ant and glued it on the top of the case over where the internal ant is, drilled a small hole and fed the co-ax through and soldered it onto the tabs of the external ant socket.Now there was about 20ft of co-ax on the external ant that i cut off which I would have thought would have been taken into consideration when the gain of the external amps was set but it works fine and is very compact again. Lucky as i didnt want to built an attenuator as it is a powered feed. It works as before velcroed on the recess in the car where the clocks live with only a small view through the windscreen.You may want to try it as its very neat and can be dropped back into your pocket again with no lead un-plugging.Insidently, just before it "died" it lived in my jacket pocket with my 6600 up against it for a few days. My car was broken into last week and the theives missed the receiver in the dark but I then took to taking it out of the car just in case and keeping it in my pocket.Now the thing is as i said it was in my pocket with my 6600 at work, the mobile network is very poor and the phone continually transponds at full power right next to the receiver. I am not saying thats what did it but the gain did slowly drop off in that week. If you do get a replacement for the mmic would appreciate a pm.

Cheers

Tarquin

Vic · Posted: Thu Apr 14, 2005 12:44 pm Post subject:

Hi Tarquin, Interesting stuff.

I found that the Low Noise Amp was a BGA622 by the 'BRs' ident on the top of the chip

By scouring through datasheets and with a bit of luck I found the one for the BGA622 Here

Look at the bottom of page 4, the small table identifies the package marking BRs as being BGA622 in an SOT343 package. So, that's the one we're after! I have tried a number of suppliers including Farnell who say they have no plans to stock this item. They do have what look like equivalents but typically the pin-outs are different and with these sort of frequencies you can't mess about with patch wires!

I thought initially it was possibly my mobile phone that destroyed the chip but now I am convinced it is static electricity. Particularly pertinent that two years after Infineon released the datasheet for the BGA622 it releases another one describing how to counter it's destruction by static! Perhaps the Leadtek unit's case is of a poor type of plastic when it comes to this.

If you find a source for this chip, let me know!

Vic · Posted: Wed Jun 01, 2005 7:55 pm Post subject: Fixed It!

A friend of mine managed to acquire a few samples of BGA 622 from a supplier. Soldering in the replacement was easier than removing the old chip. My GPS unit is now working well again on its internal antenna. Success! ..no thanks to Leadtek!

Vic

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