Marc3.4V6

iTrader: (1)

I removed my memphis 75wx4 amp to install some sound deadening. I took some decent pictures before I removed it as I know nothing about stereo equipment, this amp was installed professionally by a previous owner. As it turned out I drove the car for a few weeks before I re-installed it, not the same day as I planned, and my decent pictures weren't good enough and my memory faded on how to put it back together. I tried and honestly I don't see what I could've done wrong. Also, none of the speakers worked with he amp removed in those 2 weeks, is that normal?

Here's some pics before I removed it







The set of skinny gold wires on the left, I figured that they were suppose to be installed silver then gold from left to right, but is there exact placement as before important? If so, I think that may be the problem and I have no idea how I would find out which wire was originally where.

JTom

Check the main power fuse under the hood near the battery. If you didn't remove it before pulling the wire then you shorted the 12v and ground and likely blew the fuse. You may have also shorted the blue turn on lead so take a multimeter and see if you have 12v with the key on.

As for the speaker wires, copper is typically + and the silver is negative. Take a 9 volt battery and put copper on the + terminal and silver on the - terminal. Tap them briefly a few times and that will tell you which speaker it is connected to. Then just match up your RCAs to your before picture.

Marc3.4V6

iTrader: (1)

Thanks JTom, forgot to mention I disconnect the battery before removal, I think. Also, the 12v and ground wires - I accidentally touched them and they sparked, I'm guessing that may have blown a fuse as well.

pentavolvo

get a 10 dollar voltmeter

Marc3.4V6

iTrader: (1)

I've got one, thanks. I won't be able to mess with it for a few days, though.

Marc3.4V6

iTrader: (1)

Here's the fuse I think is blown. It had a glass tube inside the case, and the inside of that had black-ish metallic colored burns, guessing it blew. How do I find out what fuse to get? The only markings on the wire I can see say "8 awg wire" and "100ft" on the long side. I'm guessing I can just replace the short battery side wire, but do I have to cut and crimp the end of the long side with the new fuse?

Daniel Richards

iTrader: (1)

OK, please if you really have this little of a clue as to what you are doing let someone that KNOWS what they are doing fix it.

it looks like you pulled the fuse itself apart, the metal "prong" in the second picture, the "glass tube" in the last picture and the other half of the metal "prong" on the other wire are all the fuse (the metal ends of the fuse insert into the metal connectors that are attached to the wire), here look at the picture for this fuse holder
there is NO CRIMPING involved in changing a fuse.

as for what size fuse to install there is not written on the WIRE it's on the part of the FUSE that is still jammed into the outer section of the fuse holder.

Marc3.4V6

iTrader: (1)

Figured as much, I unscrewed each end to take a closer look because there was empty space between the prongs. When I unscrewed it the fuse came apart. Thanks for the help.

Bengi09

Take it back to the shop that did the install or another shop, the tech there shouldnt even have to pull your car into their bay and it shouldnt be more than 20 bucks to fix it. I wouldnt even charge anything except for the new fuse.

Marc3.4V6

iTrader: (1)

Thanks for all the help. I got the fuse, it was a 50 amp. I guess I could also add up the two 25 amp fuses on the amp itself to get it also. The speakers sounded messed up or weren't working in the fronts, so I figured something got mixed up back there. Then I used the 9 volt battery trick to match up the correct speaker wires. They still sound messed up and I don't get much out of the door speakers, sometimes bass comes through but nothing else and what does come through is in the back and is just a bit muffled. Sounds a bit static-y as well. Is it possible I blew a few of the speakers when the main power fuse blew initially when I started this thread? I would assume that's the purpose of the fuse. It was getting dark so I had to give up for the night, I'll see if I missed something tomorrow morning.

Also, when testing the speaker wires, nothing came from the door speakers that I could tell. The "RF" and "LF", Left Front and Right Front wires popped the middle speakers that are behind the driver and passenger seats. So does the amp not power the front door speakers, or does it power both the door and middle speakers with the RF and LF slots and I just didn't hear it during the test?

Marc3.4V6

iTrader: (1)

Ok, so the ground wasn't in all the way on the amp and it sounds more like it did before. Maybe even exactly and I'm just now noticing it's real problems. So it seems like about 98% of the sound is coming from the middle speakers. It is clear sounding now, but the door speakers have a hiss and some bass and the rear hatch speakers have more hiss and less bass, if at all. I always thought the system sounded off, like it was coming from behind me but I put it off for another time. Now I want all my speakers working. I can test them with a multimeter, right?

SSellers

Godalmighty man. I won't say anything more than chalk this up as a learning experience.

Search around on here and elsewhere and I'm sure you can find the wiring color codes for the speaker outputs. Or get a Haynes manual which should list them. See how that bundle of wires runs down to the harness that is all taped up? Those are going to your speakers. You have to get the correct outputs and polarities at the amplifier going to your speakers. You're going to have to seperate that bundle so you can see what each set of wires is and then connect to the correct spot on the amp.
Ex: If the drawings say "left front = blue positive, yellow negative" then find the set of blue/yellow wires that are connected to the silver/gold wires and connect to the correct left front spot on the amp and so on.

Marc3.4V6

iTrader: (1)

Forgive me, I've never done any wiring before. I've done all kinds of wrenching to my personal cars and tons of autobody work (do it for a living) but stay far far away from wiring, yes even stereos. Figured it wouldn't be too tough but I'd have to start from the bottom..... and I didn't want to pay anyone to do it. lol. Let me know next time you get into something you know nothing about and I'll be sure to bust your ***** about it

I already have the amp working to how it was before. I used the 9 volt battery test and listened to which speaker popped when touching the pair of wires to the battery. But I now realize that the door speakers never really worked, those and the far rear speakers are blown or at least partially blown. I bought the car recently and didn't use the stereo much before I unplugged it and blew the fuse, but it did seem like much of the sound was coming from the back. Now it's obvious why. I haven't had time yet to take the door panels off and check the speakers yet, but I'm guessing that the cone inside is separated somewhat as I do get muffled bass fromt he front but not much else. Thinknig about replacing them with Alpine SPS tweeters and 6 and 1/2 speakers. They are 4 ohms as opposed to the 2 ohm factory but they should work fine as people seem to have success with using them even with the stock amp.

I'm still not clear though about where the front speakers get their power. There are 6 speakers in the car, but the amp only has connections for 4 speakers, and there are only 4 pairs of speaker wires in the loom for the positive and negative of each individual speaker. When you use an aftermarket amp, does it work together with the stock amp? I'm thinking that may power the front speakers?

Thanks for being patient with my lack of experience. It's real easy to treat someone like they're stupid just because they haven't done something before. All I needed was a little general direction and already I don't feel intimidated to get down to business with the stereo system, or perhaps the entire wiring harness of a 747. Thanks.

Daniel Richards

iTrader: (1)

I think at this point your best bet is to pull out enough of the interior that you can trace every wire running from the amp to the speakers. Typically if you have a 4 channel amp then the original amp was probably bypassed, It's also possible the HU is pushing one set of speakers while the 4 channel handles the other 2 sets, another possibility is that 2 sets of speakers are spliced together at some point in the wiring, unless you trace every wire and draw us a diagram of the wiring it's going to be hard to help you.

FYI, the only speakers in the car that are 2 ohm are the sail panels, but they might not even be 2 ohm because if there is an aftermarket amp this is a chance the Previous Owner swapped them out at some point.

Some other things that you can test to see if any of the 6 speakers are being run off the HU is to disconnect the 4 RCA wires plugged into the amp and then see if you still get any sound from any speaker at all, if you do then those may still be going thru the factory amp (if it's still there at all) or run directly off the HU.

Also if you could snap a picture of all the settings on the side of the amp (same side as the RCA's) perhaps the settings may have gotten bumped around switching you from a full range to a high pass (blocking most bass from those channels) or a low pass causing only bass from those channels (which could sound like a muffled sound and then you turn the volume up to high and cause distortion).

You can test if 2 speakers are hooked to one channel by fading the HU all the way to the front/back and balance left/right, this will allow you to theoretically send sound to only one speaker at a time, like if you balance all the way to the right and fade all the way forward you should only get sound from the passenger door and just work your way around the four "corners" of the fade balance (this will also allow you to confirm you have the speakers wired to the proper outputs on the amp, assuming the RCA's where put back perfectly right, in much the same as the 9-volt test).

Mr.z/28

iTrader: (8)

Id get a 0 gauge wire that thick fat wire for your battery. thats what I did since the standard skinny red wire kept melting at the fuse.

Marc3.4V6

iTrader: (1)

Great tips, thank you. I'll check that this weekend. The factory amp is still there. I didn't know that the head unit could run speakers, makes sense. And yes, the sail panel speakers are aftermarket. I did change one setting, the crossover for the front to the middle I think, it was on lpf to the right, that's what made it sound like it did before I removed the amp.

Daniel Richards

iTrader: (1)

OK, just an FYI, the "front" on your amp setting should control your front door speakers and the Crossover of the front should be set to either FULL or HPF, FULL will allow all sound to come thru the the door speakers, but if your getting to much distortion from the bass on those speakers then I would suggest switching the crossover to HPF, HPF will allow you to block the lower frequencies (bass) from the doors reducing there distortion, the exact cutoff can be adjusted using the HPF ****, I typically set the HPF in my HU to about 100-125 Hz, also Bass Boost for the front should be on whatever the lowest number is, and I can't make out what the setting below that is, I could really use a picture of the actual amp.

Marc3.4V6

iTrader: (1)

Daniel Richards

iTrader: (1)

OK, couple things, have you tried the fade/balance thing I described to make sure only one speaker is connected to each channel of the amp?

I would go ahead and switch the "front" crossover to HPF and adjust it to somewhere around 80-125 Hz (it goes from 50 to 1,000) to cut bass from them so they won't distort so easily.

You said the sail panel speakers had been replaced, what is in there now? knowing this I can give you advice on tuning the "rear" settings on the amp.

Marc3.4V6

iTrader: (1)

So I thought I had it back to how it was before but I was wrong. If the engine is running there is a lot of feedback. I can hear the turn signals in the speakers and there is high pitched whine from the speakers when I give it gas. I guess I have to recheck the ground. I noticed the body ground near the amp, which I never removed, is grounded to metal yes, but not bare metal, would it make a difference if I sanded the paint off to bare metal for the body ground?

I used the fade/balance to go to the front left only and I could only hear the sail panel speaker and bass again in the front left door speaker. HPF only seemed to lessen the clarity and volume from the only speakers that were working. I actually painted my mirrors today so I had the door panels off and I saw some unexpectedly nice looking speakers, 85 watt "Soundstream" speakers. I think it said "picasso series" on the inside. I didn't have time to mess with them and find out why they aren't working, but may tomorrow while I'm repairing my cracked door panels. I may end up taking it to a professional but I appreciate the help in getting me this far.