The car amplifier doesn't provide a signal to the sub
I have the most perplexing of issues at hand, and I don't know where else to turn to but here.
My sister's car -- namely, the car's sub amplifier -- is giving me all sorts of sass. I'm trying to diagnose it from a world away (she's in Tennessee, I'm in California) and it just does not want to work properly.
A bit of background: I sent her my old subwoofer and amplifier because her setup stopped working awhile back, and she was unable to take her old sub+amp up to Tennessee when she moved anyway. So, I shipped her my sub+amp in "known good" condition, and my amp just flat-out refused to work. It powered on briefly (the yellow LED on the amp itself turned on, but not the green LED on the subwoofer level controller), but turned off as soon as she hooked up to sub... And then it never powered back on again.
So after some brief multi-metering, we chalk it up to a bad amp and she orders this Boss amp from Amazon.
Yesterday the amp arrived, and we're back to square one. These are her installation pictures: pic #1 and pic #2. Please refer to them, as I will be using the specific names found on the amp. This is what I know, according to sister:
- The green Power LED is lit, and the Protection light is *not* lit.
- Batt+ and Ground have 12.8ish volts across them when measured with a multimeter.
- Remote and Ground have some negligible voltage across them when measured with a multimeter (and the radio is on) -- but that voltage goes away when the radio is turned off. So I'm assuming that the amp gets a signal from the radio to turn on.
- Speaker Connections have 0 voltage across them.
- I had her test the continuity of the sub by measuring across the subwoofer terminals. Since the multimeter doesn't have a "continuity test" mode, I had her do the old-school Ohm method -- setting the meter to 200 Ohms. With multimeter leads not touching, the multimeter reads 1 Ohm. With leads touching, it changes to 0.1. So touching something that has continuity should change it to 0.1. She tried this on the 30 amp fuse on her old amp, and the method worked (the multimeter changed to 0.1). However, when she puts the leads on the subwoofer terminals, no change happens. But if she connects the speaker cables from the amp to the sub and performs the same test, the multimeter reads 0.1.
So that's where we're at. I basically have three questions:
- Should the Speaker Connections read 0V across them? I thought that there should be some voltage coming out of those terminals that would indicate that sound was being output.
- Piggy-backing on the previous question, I'm curious if there would be any voltage coming out of the Speaker Connections if the RCA audio jacks were bad (basically the audio signal coming from the radio). So a) would there still be a voltage coming through Speaker Connections, and b) does anyone know of a good way to test if an audio signal is coming from the radio through the RCA jacks? I would have her do the Ohm method for continuity, except the opposite ends of the jacks are like 15 feet away, one side being by the radio, the other in the hatchback area.
- Should the multimeter Ohm reading change when she measures the subwoofer terminals? As far as I recall, the sub is wired in parallel internally (it's a dual coil Rockford Fosgate Punch HE2), but I assume that it should still read some resistance value that is not 1. I figure that even if the sub had tons of resistance, the multimeter reading should spike to some other value, since the multimeter was put on the lowest possible Ohm setting.
The issue is that the sub is encased in a completely sealed enclosure, and she'd have to tear the whole thing apart in order to ensure the wiring is fine. So I'd love to be able to *not* have her do that if at all possible.
Thanks in advance!
Is this a good question?