Phone Mute - Pre 2000 Models

[IanF]

I know this has been done to death before, but all the info I find is related to the post facelift models.

Does anybody definitively know how to mute the 1st generation stereo, with CD slot at the bottom and external amplifier?

I have read several options - one says it's the pin at 0.5v and anther says its the pin at 4.5 - 5V.

Yet another says there are 2 pins on the external amp that mute it. Indeed, if you open up the amp, 2 pins on the circuit board are labeled at MUTE and T-MUTE. Unfortunately neither of these actually mute the stereo when grounded.

I have spent a bit of time poking in the back with a multi-meter tonight to find the voltage of pins at the back of the stereo:

The connector on the left is full - and none of the connectors would appear to be a mute.

There is nothing plugged into the right hand connector. Measuring voltage from each gives the following:

1 - 11.8v

2 - 4.8v

3 - 0.03v

4 - 0.05v

5 - 3v, but decays to 0 when the MM is connected

6 - 11.8v

7 - 0.02v

8 - 2.46v

9 - 2.46v

10 - 0.03v

11 - 0.11v

12 - 3v, but decays to 0 when the MM is connected

Of these, pin 2 seems to fit the bill of one potential suggestion, and indeed the stereo goes silent when it is grounded, and resumes as soon as the connection is broken.

On the surface this would seem positive, but I am aware that randomly connecting things to earth may well make the stereo go silent, but is not necessarily doing it in a way that is healthy to my long term listening pleasure.

Can anybody confirm or deny any of this?

Cheers

Ian

[MrADeveci]

Of these, pin 2 seems to fit the bill of one potential suggestion, and indeed the stereo goes silent when it is grounded, and resumes as soon as the connection is broken.

←

That's the one mate ............... ;)

[Geoffers]

I can't 100% remember but think think it is pin 2 on the older models, pin 4 on the newer models. The wire is Blue/Orange on the newer models if that's any help.

I may be wrong, but the older stereo doesn't pause the CD on mute does it?

A workaround is to use a standard relay. Cut the ignition/accessory wire to the stereo, and put on side of the cut wire on to pin 87, and the other on 87a. put the mute wire from the phone kit onto 85 and 12volts on 86. This will cut the heaunit when you use your mobile, and bring it back in when you've finished at the same point on your CD. (Which is always at a good bit when the phone rings)

Or, you could put the Prolex combo aux telephone input on it. It will put the telephone conversation through the headunit on a call. (Volume controlled by headunit too). It will also give an auxilliary aux input for mp3 player as well.

[IanF]

Once again, thanks for the help guys

I may be wrong, but the older stereo doesn't pause the CD on mute does it?

You're correct - the CD doesn't pause

[Dizz]

Once again, thanks for the help guys

I may be wrong, but the older stereo doesn't pause the CD on mute does it?

You're correct - the CD doesn't pause

I realise this thread is seriously old & Ian doesn't even drive a Lexus anymore :P but how exactly did you connect into this pin seen as there's no block connector going into the back of the head unit? Am fitting a Bluetooth phone kit myself & trying to figure out how to mute with the standard head unit :(

[lee_iceman]

You could either solder it on, or try and find a plug, or a connector small enough to fit over the pin.

[Dave W]

That's the one mate ............... ;)

Yep, it's definately Pin 2 on the older (CD slot at the bottom) radio models. I successfully installed my Nokia Bluetooth kit (CK-7W) last night, and mute function worked fine when on a call.

The only think now is to work out a more permanent way of attaching the mute wire. There is a connector block going into my radio (have read somewhere that other people don't have that.... maybe it's because I have the Navigator?) I guess I should be able to track down a pin that I can crimp on the wire and push into the back of the block.

Dave