P80 Radio amplifier question?

Post by **scot850** » 25 Feb 2016, 16:54

I have collected several amplifiers for P80 radios that don't come with pre-amplifiers (e.g. SC-900 and SC-901). I pull these when I see them left at PnP along with the cables as so many people pull the radios but don't take the amp and the cable (cable is NA/obsolete).

My question is this. Up until a month ago when I finally repaired my car I had no way of testing the units to ensure they were good, but now a good friend overseas needs one of these, I naturally want to ensure it is working ok before sending it as shipping is expensive.

The amps I have fit under the RH ( passenger seat in US and Canada). I want to test these without having to pull the passenger seat to get to the cables, but was thinking I could use a spare cable and connect into the radio directly to test the amps?

Finally to the question, are the 2 mounting bolts an earthing point for the amplifier, or just mounting bolts? I can't find a wiring diagram that is clear, so if one of the great minds out there can advise I'd appreciate it. As the cases are coated, I'm thinking they are just mounting bolts.

Neil.

Post by **BEJinFbk** » 25 Feb 2016, 19:51

IIRC, Should be plug and play.

Post by **scot850** » 25 Feb 2016, 23:30

I agree it should be plug and play, my only concern is if the casing is earthed through the mounting bolts to the car frame. Not earthing them may cause problems for my car and the unit. Like I said, if the units it painted then the chances are the unit earth through the wiring system, but as I don't have the wiring drawings I can't see if the unit shows as earthed through the casing.

Thanks for the input though.

Neil.

Post by **rspi** » 26 Feb 2016, 08:30

The ground is in the harness.

Post by **scot850** » 26 Feb 2016, 16:21

Many thanks for the clarification on this Robert. Much appreciated!

Neil.

Post by **bmdubya1198** » 02 Mar 2016, 12:23

Well, this thread isn't very old at all and I'm not going too off topic here, so I'm going to go ahead and shoot out this question...
I grabbed the under-the-seat amp today at pull a part, and I didn't get the wire harness, as I was strapped on time and couldn't figure out where it ran to. It looked like it went behind the glove box, but I'm not sure.
The harness runs under the carpet, up the center stack, and to the radio, correct? I'd like to install it in my car, but I want to be sure. If it's a lot of work requiring the dash to be removed and such, I'd rather not.

Post by **scot850** » 02 Mar 2016, 13:22

You only need to remove the center console and passenger seat.

For the passenger seat remove the 2 x 14mm front mounting bolts first and then move it forward. Remove the inner 14mm rear bolt and just loosen the outer bolt by the 'B' pillar. Tilt the seat back. This will allow you to access the amp under the seat and undo the 2 x 12mm bolts holding it down.

Remove the center console. It takes only a few minutes and the RH foot-well inner kick-plate.

Now to the amp cable.

The cable feeds through the carpet under the inner seat rail and then runs up the side of the center tunnel. It has a barbed connector with an cable tie through it just in front of the carpet into the floor.

There is then a couple of ways I have seen the cable routed, but both are essentially the same. There are 2 small barb connectors that feed through the side of the gear-shift plastic surround on the RH side. They are accessed from inside the gearshift tunnel just in-front of the gearshift. Use a long nosed pliers and you can squeeze the barb and they pop out. The difference in the way the wire is routed is some run inside the metal side support and some on the outside. If it is on the inside you may have to undo the support but it is only 1 bolt.

Then the cable can be removed after disconnecting them from the radio connectors behind the radio. The hardest part of removing them is Volvo used a sticky 'anti-rattle' foam to cover the join and it becomes slimey with age. Both connectors have a 'button' to depress to separate.

Fitting to your radio/car is the reverse. Take the 2 connectors from the back of your radio and plug them into the cable and the other end runs to the amp. The new cable ends from the amp cable connect into your radio as normal.

As always make sure you have your radio code. Also suggest you may want to test the amp before dismantling your car to install it. They are normally reliable but they can fail with age. I have just tested 4 I have in my stash today and they all worked as intended.

The cables are now NA from Volvo so worth pulling anyway. If I see one in a car I will always pull the amp and cable. Takes about 20 minutes with practice. Takes way longer to clean the 2 connectors of the Volvo foam covering (I use a lot of GOO-gone and a rag or paper towel).

Lastly, if you break the 2 mounts on the side of the gear console, you can use a long cable-tie to hold the wire in place by utilising the 2 holes where the barbs used to sit.

Neil.

Post by **bmdubya1198** » 02 Mar 2016, 14:25

Alright, good to know, thanks! I'll likely be back there this weekend, and I'll grab the wiring, and hopefully whatever else I can find. I'd like to be able to get everything I need this time instead of having to go back weekly, or even 2-3 times a week like I've done a couple times.

Post by **scot850** » 02 Mar 2016, 15:48

Any other questions on this feel free to PM me.

Neil.

Post by **bmdubya1198** » 05 Mar 2016, 17:22

Just got the wiring today and hooked it up to my SC-901 to test it. Everything works great, and the sound quality is amazing! I plan on running the wires through the console tomorrow. Thanks for your help, Neil!