Post by
Trimble Epic »
https://forums.nicoclub.com/trimble-epic-u217168.html
Tue Mar 12, 2013 8:14 pm
So, today, after taking care of title, registration, plate and insurance updates, I was ready to start playin' around.
The previous owner had installed an amp and subwoofer in the back and they "aren't included" ... so he took 'em out. unfortunately, he didn't reconnect anything.. just left the wires laying in the back.So, the car was without sound when I picked it up. Sigh. The hour long drive home yesterday was boring. Oh, and he had mounted his amp to the back of the back seats, so the wires were exposed visually to the trunk.
Today I got to work on fixing the sound system. At first, I assumed I was going to need to re-run the wires from the speakers back to the head unit (instead of the trunk) to use the HU's built in amp... But then my father-in-law offered me use of his old 4 channel amp. I drove over to his place to try to find it. alas, I could not find it... However, I was able to find a little(25w x 4) old 4 channel amp that I bought 20 years ago and never used... it was sitting in a box in his garage attic (I used to live in his house shortly after I married his daughter). I didn't even know if the damned thing works... Well, I grabbed it and went home.
Back at my garage, I started to survey the damage... Hot and Cold power lines, remote turn on lead, four RCA interconnects which I assumed were the four channels coming from the HU, and four speaker wires... But, wait... what the hell? He had installed spade lugs on all the wires, but he had combined the speakers onto the lugs... presumably the right front and rears were gang'd and the left were similarly gang'd... I guess he was using two of the amp's channels to run the sub and didn't care about front to back imaging.
I connected the power lines and the little amp's power LED lit up. Well, that was promising.
Nothing was labeled, so first I had to figure out which speakers were which. If there's anyone who doesn't know how to do this, here's how... First, I went ahead and connected all four line-in cables to the inputs, and set the head unit to center both balance and fader. I snipped all the spade lugs off of the speakers wires to liberate them, then selected one at random and connected to the amp's jacks for right front + and -. The right rear speaker played sound! I labeled the wire pair RR. Then I connected another random speaker wire to the same jacks on the amp... The left front speaker played! I continued doing this until all four speaker pairs were identified and labeled...
Now that I know all four speakers play independently, I decided to try to find a home for the amp. I pulled up all the carpet and hard-boards and found a spot next to the spare tire (yay, it'll be hidden AND have air space!). I then reconnected all the power leads and input leads and now permanently connected all four speaker wire pairs to the amp.
Next step is to figure out if I actually have the input leads right. So, I go to the head unit and adjust the fader control to all the way to the front. Turns out I had the front and back wired up backwards, so I just swapped those, and now the front and back are correct.. Next, I set the balance to far left, and only the left speakers played... That was a gimme because the RCA cabled were color coded (red and white), so it's hard to mess that up...
...but wait.. I noticed that both rear speakers were playing regardless of the balance setting (left or right)... After some fiddling, I figured out that the head unit was set to subwoofer mode instead of rear channels mode, which means it was combining the signal and sending the same signal to both right and left rear channels. Changed the setting and now all is well. All four channels are playing as they should, and fader and balance controls work as they should. Yay! and it didn't cost me anything to fix!
Sorry I didn't take any photos, it just didn't occur to me at the time that I would write about it, but I'll try to snap some for the next job. There's lots of little jobs to do on this Z. (For example, I actually found an OLD BAG STYLE CELL PHONE UNIT next to the spare tire, along with supporting cables. WTF?? were we still using those when this car was made in '93? good lord... Anyway, I'll need to remove those unused cellphone cables. My iPhone doesn't need that crap.)
Oh, I hope I didn't bore anyone with this write up... I figured maybe SOMEONE could learn something about how to figure out which wire goes where...
I trust that is a good thing.
