S70R Dolby problem

moynesey · Post by **moynesey** » 09 Jan 2011, 14:24

Hi all,

I am new to this forum and have a question with regards to my 1997 S70R. The car has the SC 900 and 4x50w amp already fiited. I have recently got from a C70 the dash top with centre speaker and also the Dolby Pro Logic decoder, i also got the centre speaker wire from the speaker to the green plug that plugs into the head unit.

I was expecting the wire to already be there, but it wasnt, can only assume previous owner had removed it when he fitted an after market headunit (which i took out and replace with the SC 900 it still had with it).

Decoder is working perfect but there is no sound from the centre speaker. Before you ask i have it in Pro Logic playing CDs and have turned up the centre speaker volume on the front but still no sound.

The green centre speaker connector has only three wires from it, two blue with stripe for the speakers and the third being a black cable not connected. I assume this is an earth but have read and been informed that other S70's with Dolby have 4 wires, the fourth being a brown wire?

My questions are, do the later SC901 unit only have three wires from this plug? Am i missing a wire and if so does the fourth wire carry power to the internal amp with the black earthing it?

Have search about with no luck, any help will greatfully be recieved, its beginning to get on my nerves !!!??!!

Thanks in advance

Post by **JDS60R** » 09 Jan 2011, 14:28

Wiring diagrams are above under "Repair Database"

moynesey · Post by **moynesey** » 09 Jan 2011, 14:42

Hi, thanks for the quick reply.

Looked there before asking, but from what i can tell it only shows the two speaker wires and neither a third or fourth. Could be reading it wrong but i cant see where those wires go?!

Post by **BEJinFbk** » 09 Jan 2011, 15:19

The center channel speaker only needs two wires.
These:

Before tearing this up much more, you may wish to check the speaker.
The early version was prone to broken magnets that can lock the voice coil.
The replacement is designed with a reinforcing bolt through the magnet.

Are you hearing the surround from the rears in Dolby mode?

moynesey · Post by **moynesey** » 09 Jan 2011, 15:23

Hi,

That wiring arrangement makes more sense to me, when in Dolby mode you get all the effect such as surround from the rears but no centre channel.

Post by **BEJinFbk** » 09 Jan 2011, 21:00

My magnet snapped one morning on the way to work.
I hit a bump, there was a loud "crack!" followed by silence from the center...
( Maybe it was the -40 is sat outside in all night. Who knows?

)

New Speaker? About $112.00 US.
Surround with a center? Priceless!

moynesey · Post by **moynesey** » 10 Jan 2011, 06:10

Checked the speaker today and you were spot on the inverted voice coil has had it! Ran another speaker and i works perfect.

Hunt now on for another centrespeaker.

Thanks for all the help, the only forum ive asked who have bothered to reply!!

Post by **BEJinFbk** » 10 Jan 2011, 15:23

I have the new number for the LHD version, but not the right. Sorry.
I'd expect that a dealer should get you sorted with no problem, though.
Enjoy!

Post by **JRL** » 10 Jan 2011, 15:47

moynesey wrote:Hi,

That wiring arrangement makes more sense to me, when in Dolby mode you get all the effect such as surround from the rears but no center channel.

NO YOU DO NOT
ALL three (3) of my Volvos have this radio, one with a center channel, two without.
The two WITHOUT a center channel have no provision for Dolby.

Push the mode switch and nothing happens, it stays on stereo only!

Post by **JRL** » 10 Jan 2011, 15:48

moynesey wrote:Checked the speaker today and you were spot on the inverted voice coil has had it! Ran another speaker and i works perfect.

Hunt now on for another centrespeaker.

Thanks for all the help, the only forum ive asked who have bothered to reply!!

Bite the bullet and buy new.
These are junk speakers and do not last very long. Buy used and it may last a month!