QuestionQUESTION: Hi Justin,
At 1st there would be no sound from my speakers and it would come back on its own after a key cycle or 2, but last week i heard a pop come from all speakers and then no sound or door chimes. I can see the head unit is working, the diplay shows songs playing cd/tape info etc. but no sound/door chimes until i reseat the 30 amp amplifier fuse,then i get sound/door chimes out of my left rear speaker only until the next key cycle, were i have to reseat the fuse again.
How do i tell if the amp is bad or speakers are bad or if it is a short?
I have an old sony xplode i can install in case i have to bypass the amp or can i use my stock head unit and bypass the amp.
Im worried about short something else out on the vehicle if i leave it as is, any help would be greatly appreciated
Thank You
Mike
ANSWER: Hi Mike,
Testing this sort of thing can be a real pain in the butt. My first suggestion is speakers; I think you have a short somewhere, and the amp is going into self-protect mode.
First, to start, disconnect the speakers, and test their impedance with a multimeter. They should be about 4ohms.
If that checks out, reconnect the speakers, and test the leads going to the speakers at the amp. The impedance shouldn't change much.
If your car has a factory amp and deck, you won't be able to bypass it and get signal to the speakers; the deck will only be outputting a low-level signal with no internal amplifier, so you'd get little to no sound out the speakers.
Justin
---------- FOLLOW-UP ----------
QUESTION: Thanks Justin,
This may sound dumb, but do I check the speakers @ the speaker itself or the
harness into the amp or both (continuity on the speaker wire themselves). I have
an older style multimeter (dial type) and I'm not to sure on how forearm ohms, but
I'm sure I could do a search for that as well. I guess what I'm asking, are the speakers
bad if they have more than 4 or less than 4 ohms. Also I was reading that these speakers
are 2 ohms. Can I just disconnect the bad speaker without affecting the vehicle other
than sound quality.
Thank you
Mike
ANSWER: Hi Mike,
Disconnect the speaker from all connections, and then touch the two speaker terminals with the multimeter leads. If they're 2 ohm speakers, then they should read ~1.8-2.2. The bigger concern is if the impedance is LOWER because this will cause the amplifier to shut off to protect itself.
If that checks out, reconnect the speaker, and then disconnect the connector going to the speaker from the amplifier, and touch the leads to the wires going to the speaker and see if you get the same(ish) reading. If it's lower, there's a short. If it's higher, there's an open spot.
You could disconnect the speaker without adversely affecting anything, but it won't sound quite right.
Justin
---------- FOLLOW-UP ----------
QUESTION: Thank-you Justin I will try again this weekend, I disconnected the harnesses from the amplifier to see if by removing the wires @ the harness & plugging back into the amp 1 x 1 if that made a difference, bit no luck , it seems there is alot of work getting to each speaker & I was trying to save some time. I woke up this morning to go to work & my battery was almost dead, must be a short somewhere, I tool out the fuses to the amp & HU @ work and my battery seemed ok, I'll leave them out overnight to see how that works . You said that if the ohms are lower it could be open , I'm not quite air what you mean by that.
Thank-you
AnswerHi Mike,
If you touch two wires together, their impedance drops to close to 0. This is bad. It's a short. If you have a short, then the amplifier will either fail, or detect it, and shut that circuit off to protect itself.
If the impedance is too high it means there's a bad/corroded connection somewhere.
Justin
