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     Chris Miller Prolific User Username: cjm51213 Post Number: 298 Registered: 5-2013 |
Hi Folks, Over Thanksgiving, I replaced my legacy audio with something more contemporary. The new unit plays AM/FM/Optical/USB media, Bluetooth cellphone integration, GPS turn-by-turn navigation, and rear-view camera, all controlled with a touch screen. The '72 had the original radio (AM/FM/8 Track!) mounted in the console just below the heat/air conditioning vent and a previous caretaker augmented this with a second AM/FM radio just behind the cigar ash tray in the center console. I suspect the addition, instead of a replacement was due to console trim considerations. Removing the original unit leaves a hole in the console, which I will eventually have to repair, but I have plans to mount a tablet there, so it is not a problem for me. This installation was done exactly how I'd have done it, so it was easy to understand – they installed a four channel relay and a switch to select which of the two would drive the speakers. The sound was really bad. It was distortion and static, which I assumed was the speakers, but it turned out not to be the speakers – it was the old radio units or the installation or the modifications to the wiring or some combination of any of these. First problem: Replace the speakers. I bought really good high-end speakers which quickly tuned out to be the wrong thing. There was limited depth in the doors and all the speakers available required greater depth than I had available. I found speakers that fit the bill. I used Kicker 4OCS5, 225 Watt Peak Co-Axial Speakers. These are nominal 5¼” speakers. The speakers I removed looked to be in pretty bad shape with a fair amount of flaky rust. Taking a hint, when I installed the new speakers, I covered the back in plastic, insulating them from any incursion of rain water in the door. (To do this, make a cone of plastic with the speaker wires traveling through the apex of the cone. I used a long cone, like a wizard hat. I also covered the backs of the door trim panels with plastic, since I was already there.) Second problem: Fabricate a new center console. The original console was probably built by the caretaker who added the second radio. Since the unit I was installing is a “double high” box, it wouldn't fit, so I needed to make one that would. Third problem: Deduce which wires went with which speakers and ensure continuity. In the console I could see five wires. Gray with black was common ground. Gray with Yellow, Violet, Brown, and White were the four speakers. I used a 1.5 volt battery with a couple of scraps of steel taped to the battery ends to give my test leads purchase to test my speakers. This was sufficient to produce a scratchy sound from the speaker and not sufficiently high voltage to endanger the integrity of the speaker. Clip one side to the gray and black ground and the touch each of the others to identify which speaker went with which wire and prove that there was continuity from the wire to the speaker.  I tried all combinations and I was able to pinpoint and solve a mystery. The right side of the car had a caretaker installed ground wire, but I was able to see why. Somehow the ground spade had been moved to the other row in the connector block! I don't know when this happened, but apparently it was before the last changed to the audio system. After I fixed this, I was able to test the speakers. I tried all combinations of wires in a five-by-five matrix. Because there was a common ground, almost all cells in the matrix produced a response:
The unit I was installing wanted separate ground to each speaker. This as also easy to accomplish. I was able to remove the spade from the connection block which gave me the individual grounds to each of the four speakers, and I ran extensions to the console. I used a leather that has a much coarser surface, so the match is not perfect, but I like the "pigskin" finish, in spite of the mismatch. Here's how it turned out: General View:  Notice the fit. I've remove the driver seat cushion to show you. It really turned out nicely!  Here's a more orthogonal view:  So, now I have killer tunes and magically, the horn works! (But now the dome lights don't...) Chris. | |||||||||||||||||||||||||||||||||||||||||||||||
| Bob UK Unregistered guest Posted From: 94.197.122.79 |
Check the pull down fuse box. The job looks fine. My car has individual arm rests with a tray with fitted tack for eight track tapes. The radio CD is where yours is but much narrower. Din spec. Inplace of the eight track is an MP3 dock and mobile phone dock. They are on leads. They just sit in a hole. The MP3 works via the radio amp. 5000 tracks. When I want to load something I just take the I MP3 out of the car and my son sorts it out on his equipment which is very good. So easy and convenient. £50 for the MP3 and £10 for car charge lead with a voltage stabilizer. That's under the ash tray. The radio is dropped in and packed with wood strips. My wife pulls the mp3 player from the hole on the lead and sorts it out then pops it back in. It works great. I concentrate on driving. My speakers were grounded to the car. So I rewired the lot with din colours. To find which pair of wires go to what speakers apply a pulse of dc volts to a pair. The speaker will click. Use a little 9 volt dry cell not 450 amp plus from a car battery. Do that with old ones to see what happens. Only 8 ohms. Speaker wise I fitted 4 £5 each from maplins. 10 watt 8 ohms. The amp is 25 watts so up to reasonably loud volumes it's responsive. After that the distortion creeps in. The speakers are paper with a plastic half cover over the back. They fitted straight in. The speaker wires are soldered. Fitting modern audio in old cars without ruining the period look is difficult. This job looks ok. Old Speedo cable inners make good wire threading mouses. Boeing used real live ferrets. My dog plays with this ferret and the ferret is always so pleased to meet people. At Boeing the wiring people treated them as pets. (Message approved by david_gore) |
