Can't hear callers on Sony MEX-BT3900u

[kelvyn29]

So connected this up using the std ISO connection blocks.

Can stream music via Bluetooth  o problem but when it comes to making or receiving calls I can't hear any1 through the speakers.

I read somewhere if you switch the source to FM radio it works, have tried this with no joy.

Have emailed Sony and they suggested replacing the headinit  which I have done but still the same issues.

Both the phone & music icons are on screen.

I read some where that the light blue ATT wire might have something to do with it??

I have this in a car with A fixed aerial.

Im about to take this back and get my money back if i can not solve this 😞

I know it's not my phone issue (iPhone 4) as I paired it with their demo in store and was able to make calls and heard the other person through the speakers.

Ease help as I really do like this unit but need to be able to make calls with it.

Thanks

Kelvyn

Message was edited by: kelvyn29

Message was edited by: kelvyn29

[Drumzman]

Hi kelvyn29,

Just a thought, but I believe the volume for the handsfree on the BT3900U is completely independent of the 'normal' volume - might be a long shot but perhaps the volume is right down.  I think you have to adjust the volume for handsfree via a menu option.

The light blue ATT wire won't help in your case by the way, as this is designed for use with a permanently installed car kit/cradle that makes the music mute when the phone rings.  With Bluetooth there is no physical connection, but the music volume should be taken care of automatically anyway.

Hope this helps you.

[da__yo]

I FIGURED IT OUT!!!!!!!!!!!!!!!!!!!!!

I had the same problem you did.  I don't know what the std ISO connection blocks are but the sound from the BlueTooth phone calls goes out through the front speakers  of the radio unit so If you used the preamp outputs you HAVE TO USE THE ONE FOR THE FRONT SPEAKERS not just the rear preamp output by itself, I was only using the rear from the radio since my Sony EQ only had preamp inputs for one pair from the radio, now the default ringer on the MEX BT3900u works, I hope this helps.

[mojam2]

hi da_yo

can you explain in more detail as i have same problem, i cannot hear any sound from speakers when making bluetooth calls unless i am in the tuner source. if i am listening to tuner then i can hear calls from my phone however on any other source nothing comes out of speaker when making calls 😞

[mojam2]

also found this post on fixya forum

Eureka!!!!! The problem is solved and fixed.  This fix will work for any Sony MEX BT head unit / stereo (MEX BT2500, BT2600, BT3700, BT3700, BT5700) with a "no sound" through speakers during a call on bluetooth problem, or, no sound on any source except tuner issue, or, can only hear calls when on tuner, or, can only hear streaming when AF/TA is on

1. Find the blue and white striped wire (which is probably hanging loose in your connectors from the ISO block in the back of your head unit and likely has a female, round spade cap on it) which is the "AMP REM" wire

2. Cut off the spade cap, expose about 5mm of wire and twist it

3. Now run it back into the other blue wire coming from the same ISO block in the back of your head unit - the "Power Antenna" wire.  You are temporarily shorting/connecting both wires to test your fix

4. If you now try to make a call by bluetooth whilst streaming music, or, on any other source on the head unit - IT WILL WORK

5. Now permanently splice the two blue wires together and put insulating tape over the join

NOTE: The blue wire I am talking about is NOT the light  blue ATT wire which is probably also hanging loose

The reason for the problem in the first place was that your head unit was only correctly activating the amp on tuner through the power antenna lead - now any function/interrupt powers the amp as you have connected the remote amp to the antenna wire.

will try this........