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  • 2 weeks later...

I've had the same issue for several years ... the radio came back once or twice for a few months, then eventually went out again for good.  

AM and FM both exhibit the same problem on my unit. which points me to the component that brings signal into the unit.   My Traffic tuner seems to work fine with the Nav unit, so that tells me the antenna on the car is fine.  

Today I pulled the unit from the car again since I would like to get it fixed one way or another ... first I tried removing the Traffic tuner from the signal chain and plugged the car antenna directly into the unit, no change, so the issue must be inside the unit.

Looking at the Service manual I found the "AV PCB" board on p272 that appears to have a simple two-prong connector for the antenna cable jack.   I've attached an image of that page from the manual.  I wonder if it's as simple as solder joints on that connector.  So before I send this off to a repair shop I figure I should take a better look at it in case it's something I can handle.

Next up, I will disassemble the unit using the instructions from the Service manual starting on page 149.   The instructions are actually pretty clear so I'm not thinking this will be very difficult or risky.  I will send an update when I make more progress.

Thanks. John

 

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Okay, I took the unit apart today.  

Actually much easier than I was expecting it to be ... please note the following:

* There are only two sizes of screw heads, Philips #1 and #0.  Use GOOD screwdrivers!  Many of the screws, especially the smaller ones, are in very tight, I almost stripped one, so a cheap philips screwdriver may not cut it here.

* To release the display from those first two screws at the bottom you have to separate the metal holding tabs a bit to get them off the posts that the screw goes into.  this is a tiny post that allows the screen to swivel against the holding tabs during the opening/closing action

* The unit is made of surprisingly few modules, and they are all connected by ribbon cables.  Take your time with the ribbon cables, there are three types of connectors that I ran across:

    - flip lock bar, flips up to release cable from holder

    - pull out bar, pull it out towards the ribbon about 1/8" to release the cable from holder

    - pull out, the ribbons with a hard blue plastic tab at the end of the cable ... these you just pull out

* I've attached a photo of all of the screws I removed to get to the AV PCB assembly.  Not a great many screws.  Fyi I made a makeshift adhesive screw holder by alternating masking tape strips face up/down on the paper ... works great.

I could not see anything visually wrong with the AV PCB ... the antenna jack seems to be attached with large solid solder joints, no burn spots anywhere that I could see, nobulging capacitors.  I am posting a bunch of photos of the board, if anyone has a suggestion on what to inspect more closely let me know and I will look and/or post more photos.

Also, while I have the unit disassembled, if you have interest in what any of the other components look like let me know and I will be happy to take and post more pics.

Thanks.  John

 

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More research is pointing me to the TDA7706 digital tuner chip that sits on the riser board ... if this chip is fried then it's beyond my electronics skills to replace something like this.  A shame, it looks like this is available from multiple sources on eBay for under $5.

 

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  • 6 months later...

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