Speaker problem installing new CD head unit

[Sammo]

Right. The CR-208 was a bit knackered on the 940 I bought, so I'm trying to replace it with a Sony CD/Radio. I've followed the instructions in the pdf in the topic below:

http://www.volvoforums.org.uk/showth...t=radio+wiring

Everything went ok up until I needed to wire up the speakers. The new head unit is wired up with power, and I can see from its equalizer that it thinks it's playing something. Unfortunately I can't get any sound to come out of my speakers!

I've cut the wires from the rectangular connector that originally went into the volvo pre-amp, and the guide I'm following lists wire colours which match the 8 wires I've cut.
I've tried the battery test as suggested on the wire pairs which *should* correspond to each speaker, but no popping noise. Connecting them up with an ohm meter gives me readings of 4-600kOhm across every possible pairing of the wires.

Can anyone send some ideas my way? Thanks!

[callyuk]

have you tryed the battery test going though each wire with all others to see if you get sound? failing that it maybe worth tracing the wires back to the speakers to check for breaks or snags

[JOEM]

Re Enter The Radio Code See If It Works

[TexasGoat]

Sammo,
Re your speaker problem. I am new to Volvos and don't know CR-208, BUT,, is it possible that your old radio unit was NOT the model with an integrated amplifier? I got my '93 940 used and the electrical was butchered by some yutz trying to replace the radio. Some of the results were re-wiring (or trying to re-wire) the speakers. Part of the re-wiring goes to a long black box under the dash, which I think might have been the Amp of the old unit. Signals sent to the unpowered amp would not reach the speakers with enough poewr to make any noise (me thinks). You might also want to watch out for impedance matching problems.
If you still have the problem, and for what it's worth, try http://www.volvotechinfo.com/WD123/3...%203904202.htm, Group 39 has the diagrams for the radios. It has helped me a bit. Good Luck.

[niloc]

For future reference, instead of chopping the plug off the pre-amp wiring to connect a new radio, just unplug it and use scotch locks to connect the new speaker wiring to the wiring loom. It can easily be returned to standard at any time then.

[Sammo]

Thanks for the ideas guys - not had a chance to have a look until today though (!!)

So - I've got 8 leads that I cut from the rectangular connector that used to go into the amp. I've tried wiring up every pair of them to an external audio source (which was verified with a non-car speaker), and no joy with any of them - so I've come to the conclusion that the wires I've got can't possibly be the speaker wires I'm looking for. This would seem to be supported by the extremely high resistances I'm seeing across them.

So - I guess my next step is to trace the wires back from each of the speakers and find out exactly where they're going to under the steering column - sound like a plan? Just wondering how I'd actually go about doing it though - not sure how to remove the speakers from the dash (or how to remove other bits of dash to get to the bits behind the speakers). Any thoughts?

If it turns out that the wires I've located *are* the right speaker wires, then (at a guess) I suppose that the speakers need an external power source?

TIA for any help!

[TexasGoat]

Hey Sammo, Season's Greetings,

From your last post, I will assume that you chopped the "B" connector plug in a modern 'Radio with integrated amplifier' system. Mine was an antiquated Radio and external amplifier ( I think, it was kinda hard to tell from the missing pieces and butchered wiring, any way...). Eight wires means Pos and Neg leads to only four speakers. My 93 940 sedan has eight speakers: two in the dash (connected directly to radio connector "A" in your system, and the other six connected through 8-pin radio connector "B", the two in the rear deck, it seems, are paralelled into the wiring for the rear door speakers). An ohm meter should read a near short (very low resistance) between the leads for any one speaker (a 2, 4, 8, or 16 Ohm speaker will NOT read 2, 4, 8, or 16 ohms on the meter, that's the AC impeadance, the meter will read the resistance of the speaker windings which will vary for any one impeadance depending upon wattage). A reasonable tool to test the wiring along the connectors is a 9 v transistor battery hooked to a 'Battery Clip' with wire leads connected to 470 ohm resistors on each side ( red and black) (1/4 watt will do). Use the exposed resistor leads as your probes ( you can test continuity at a connector without breaking the connector open. The combined resistance of the 470 ohm resistors will limit the current and avoid damage to the speakers. Don't worry about polarity to the speakers. There shouldn't be enough power available to do harm to your recv'r, but tou might want to disconnect the speaker leads from the recv'r. Most of the speakers have pop off covers on the frame to get to the mounting screws (door speakers may require taking off the door panels, so test at the first or second connector). I made up the following table from the diagrams at the site I posted earlier (you really need to check it out to understand the wiring paths). I used the 'rADIO AND aMP' COLLUMN WHEN WORKING ON MY SYSTEM, (oops) but you will probablly need the 'Radio w/o Amp" collumn (I hope that it translates well). Good Luck and Good hunting (work from the speaker back to the recv'r). Goat
TRACE Radio and Amp Radio w/o Amp
Speaker Location Right Front Door Right Front Door
Component ID 16/3 16/3
Positive Lead Color Y-W (GR-W) Y-W (GR-W)
Negative Lead Color W (G) W (GR)
1st Connector Positive Lead C143 Pin 3 (A Post R) C143 Pin 3 (A Post R)
1st Connector Negative Lead C143 Pin 4 (A Post R) C143 Pin 4 (A Post R)
Positive Lead Color GR-W GR-W
Negative Lead Color GR GR
2nd Connector Positive Lead Pwr Amp Pin 3 Radio B Conn Pin 10
2nd Connector Negative Lead Pwr Amp Pin 7 Radio B Conn Pin 9

Speaker Location Left Front Door Left Front Door
Component ID 16/4 16/4
Positive Lead Color BL-Y (BL-W) BL-Y (BL-W)
Negative Lead Color W W
1st Connector Positive Lead C144 Pin 3 (A Post L) C144 Pin 3 (A Post L)
1st Connector Negative Lead C144 Pin 4 (A Post L) C144 Pin 4 (A Post L)
Positive Lead Color BL-Y BL-Y
Negative Lead Color W W
2nd Connector Positive Lead Pwr Amp Pin 2 Radio B Conn Pin 4
2nd Connector Negative Lead Pwr Amp Pin 6 Radio B Conn Pin 3

Speaker Location Right Rear Door Right Rear Door
Component ID 16/5 16/5
Positive Lead Color Y-W Y-W
Negative Lead Color W W
1st Connector Positive Lead C149 Pin 8 (B Post R) C149 Pin 8 (B Post R)
1st Connector Negative Lead C149 Pin 9 (B Post R) C149 Pin 9 (B Post R)
Positive Lead Color Y-W Y-W
Negative Lead Color W W
2nd Connector Positive Lead C3 Pin 35 (Dash R) C3 Pin 35 (Dash R)
2nd Connector Negative Lead C3 Pin 36 (Dash R) C3 Pin 36 (Dash R)
Positive Lead Color GN-BN GN-BN
Negative Lead Color GN GN
3rd Connector Positive Lead Pwr Amp Pin 9 Radio B Conn Pin 6
3rd Connector Negative Lead Pwr Amp Pin 13 Radio B Conn Pin 5

Speaker Location Left Rear Door Left Rear Door
Component ID 16/6 16/6
Positive Lead Color Y-W Y-W
Negative Lead Color W W
1st Connector Positive Lead C150 Pin 8 (B Post L) C150 Pin 8 (B Post L)
1st Connector Negative Lead C150 Pin 9 (B Post L) C150 Pin 9 (B Post L)
Positive Lead Color Y-W Y-W
Negative Lead Color W W
2nd Connector Positive Lead C1 Pin 35 (Dash R) C1 Pin 35 (Dash R)
2nd Connector Negative Lead C1 Pin 36 (Dash R) C1 Pin 36 (Dash R)
Positive Lead Color Y-BN Y-BN
Negative Lead Color Y-GR Y-GR
3rd Connector Positive Lead Pwr Amp Pin 12 Radio B Conn Pin 2
3rd Connector Negative Lead Pwr Amp Pin 8 Radio B Conn Pin 1

Speaker Location Right Dash Right Dash
Component ID 16/7 16/7
Positive Lead Color GR GR
Negative Lead Color GR-R GR-R
1st Connector Positive Lead Radio Pin 2 Unkn Conn Pin 1
1st Connector Negative Lead Radio Pin 4 Unkn Conn Pin 2
Positive Lead Color - GR
Negative Lead Color - GR-R
2nd Connector Positive Lead - Radio A Conn Pin 7
2nd Connector Negative Lead - Radio A Conn Pin 8

Speaker Location Left Dash Left Dash
Component ID 16/8 16/8
Positive Lead Color BN BN
Negative Lead Color BN-W BN-W
1st Connector Positive Lead Radio Pin 1 Unkn Conn Pin 1
1st Connector Negative Lead Radio Pin 3 Unkn Conn Pin 2
Positive Lead Color - BN
Negative Lead Color - BN-W
2nd Connector Positive Lead - Radio A Conn Pin 1
2nd Connector Negative Lead - Radio A Conn Pin 2

Speaker Location Right Rear Deck Right Rear Deck
Component ID 16/18 16/18
Positive Lead Color GN-BN GN-BN
Negative Lead Color GN GN
1st Connector Positive Lead C1 Pin 33 (Dash R) C1 Pin 33 (Dash R)
1st Connector Negative Lead C1 Pin 34 (Dash R) C1 Pin 34 (Dash R)
Positive Lead Color GN-SB GN-SB
Negative Lead Color Y-SB Y-SB
2nd Connector Positive Lead C3 Pin 35 (Dash R) C3 Pin 35 (Dash R)
2nd Connector Negative Lead C3 Pin 36 (Dash R) C3 Pin 36 (Dash R)
Positive Lead Color GN-BN GN-BN
Negative Lead Color GN GN
3rd Connector Positive Lead Pwr Amp Pin 9 Radio B Conn Pin 6
3rd Connector Negative Lead Pwr Amp Pin 13 Radio B Conn Pin 5

Speaker Location Left Rear Deck Left Rear Deck
Component ID 16/17 16/17
Positive Lead Color Y-W Y-BN
Negative Lead Color W BN
1st Connector Positive Lead C1 Pin 35 (Dash R) C1 Pin 35 (Dash R)
1st Connector Negative Lead C1 Pin 36 (Dash R) C1 Pin 36 (Dash R)
Positive Lead Color Y-GR Y-GR
Negative Lead Color Y-BN Y-BN
2nd Connector Positive Lead Pwr Amp Pin 12 Radio A Conn Pin 1
2nd Connector Negative Lead Pwr Amp Pin 8 Radio A Conn Pin 2

From the post preview, it looks like the table does not translate well. Copy the table from the post, and paste into Notepad, WordPad, or Word (or whatever you got that will accept the tabs).

[Sammo]

Thanks for that - your table corresponds to what I found: the wires from the old pre-amp don't go direct to the speakers, they go through a loom hidden somewhere under the dash (and change colour when they do so!). So I ended up snipping the wiring that lead direct to the speakers just before the loom, then running new lengths of wire off the end and up through to the head unit. Now I've got all 4 speakers going, woo!

Only problem now is that my head unit seems to be overheating... could be a faulty unit, or could be because I've not got it connected to the firewall yet (heat conduction away from the unit???). Or, could be that my heater is blowing warm air on the unit (as well as the heat from the amp!) - when I turn the heater dial to direct warm air at my feet, I don't notice any air flow down near the pedals - maybe I'm missing a tube of some sort so the hot air is blowing on the back of the dash instead??

[TexasGoat]

Whoa Sammo, Dude, Turn it OFF!
Yee hath not headed the warning of the gods of speaker impeadance!!!!!

I think your problem is related to Low speaker impeadance causing too much current draw on the output section of your new recv'r/CD player. In addition to the over heating of the output section, another symptom is low audio volume output (you have to crank the volume control more than expected to hear the output and it doesn't get as loud as expected). I think that Volvo used/used 2 or 4 ohm speakers. The unit which you have installed probablly looks for 8 ohms in the speakers. This is AC impeadance, not ohmic resistance, but the effect is the same (ohm's law: if you reduce the resistance (or impeadance) for a given voltage, the current increases (and thus, the current draw on the output transistors in what you call the head) on the output section. Check the specifications for your new player, it should state what rating the speakers should meet.

Sorry to say, the cure is replacing the speakers. You should check with Volvo or some of the other guys in fthe forum (like Niloc, he seems to really know what he is talking about) to see if they know what the Volvo factory speakers are rated (sometimes it is printed on the speaker magnet).

Bottom line, if I am right and you continue to use the system as is, you shorten the life of the electronics. Eventually the higher heat caused by the higher current draw will damage, if not kill, the output transistors.

Though, the system could last for years as is,,, but if you are noticing the heat now, the odds are against you. Some heat is normal, but if it gets too close to 'too hot to touch', replace the speakers. Not likely that the heater airflow has much to do with it. The unit should not have to be connected to the firewall to disipate operating heat. In fact, not being connected to any thing and having an airflow should help disipate energy from the unit's heatsink. Even less likely that the new init is bad. Sony still makes good hardware (except for Lithium-Ion Polly batteries) and Sony quality Control is quite good.

You might try 'Cruthcfields.com', or worst case, RadioShack for replacement speakers.

Good luck, wish I had better news for you,
best,
Goat

[dave r]

Originally Posted by Sammo

Thanks for that - your table corresponds to what I found: the wires from the old pre-amp don't go direct to the speakers, they go through a loom hidden somewhere under the dash (and change colour when they do so!). So I ended up snipping the wiring that lead direct to the speakers just before the loom, then running new lengths of wire off the end and up through to the head unit. Now I've got all 4 speakers going, woo!

Only problem now is that my head unit seems to be overheating... could be a faulty unit, or could be because I've not got it connected to the firewall yet (heat conduction away from the unit???). Or, could be that my heater is blowing warm air on the unit (as well as the heat from the amp!) - when I turn the heater dial to direct warm air at my feet, I don't notice any air flow down near the pedals - maybe I'm missing a tube of some sort so the hot air is blowing on the back of the dash instead??

I've just replaced my original head unit with a JVC CD/Radio and the user instructions warn of the 'Heat Sink' to one side of the unit getting hot under normal conditions. Might be worth checking your unit's user instructions.