Conversion Process - Electrical - Sony MEX-BT2500 Bluetooth Sound System modifications.....
This Sony model (discontinued in 2008) was a very nice product but had one very poor feature. The mic for Bluetooth audio was mounted behind the removable face plate and as a result all the reviews on the product rated the sound quality very poor. The model was readily available at bargain prices for many months on eBay during the early part of 2008. The good news is the solution is very simple - just reposition the small mic to suit your vehicle.The article by Vladislav Staroselskiy http://vladstar.com/articles.php?id=19 was the first information I read on modifying the BT200 and since then I have installed two unit with perfect results. My method is slightly different then Vladislav's solution, I decided to mount the mic outside the main unit closer to the driver.....
This is the small Elect condenser mic was mounted here......
Removing it is very easy....
It connects to a 2 pin miniature connector on a small "daughter" board on the other side of the unit....
Position of new shielded 2 core mic cable.....
Shield is chassis earthed at one end only.....
New mic cable can exit at the opening on the rear panel (bottom left side)