stereo troubleshooting

[chris71]

guys the PO put a new jvc cd player in the glove box, hooked it up to a pos speaker, when you turn on the head unit, it will play music for like a second or two and then no sound, the lights are still on on the face plate, just no sound. every once and a while i will turn it on and it will be fine for like a half hour then crap out again. sometimes i will turn it right off and then turn it on and it will be ok for a while. does this sound like it is the head unit crapping out? unfortuneatly i dont have a spare speaker laying around to test to see if it is the speaker. any input?

[Classic69]

It could be the POS speaker you mentioned. But, you might wanna check the lead wires going from the head unit to the speaker. Make sure they are wired together properly, soldered good, and taped up so they don't touch any other piece of metal and short out the connection. Other than that I dunno.

[dirtyd_nd]

I had pretty much the same thing happen to a system I put in the wife's 4runner. It would turn on, play for a few seconds then no sound. I thought the head unit was going bad cause it didn't kill the power, just the sound. It ended up being the spot a used for a ground for the amps. The floor and nut had a plastic coating on it. Stripped both spots and it worked like a champ. Not too sure if you have an amped system, but I would check the ground wire for the head unit and amp(if you have one).
Dale

[michael bustamante]

could be that a speaker wire is touching bare metal and grounding itself out. Very poss. since you only have 1 speaker hooked up. especially on a custon install like in a glove box. Also reposition the ground. theres plenty of metal to ground up to on these ol trucks. dont give up on the head unit just yet.

[corn]

It could be a few things. Check the ground first. Some aftermarket stereos ground better through the antenna & makes a small gorund loop sometimes. Also, check to make its not getting hot in the glove box. The thing that I think it probably is, is the fact that you only have one speaker hooked up. Either they hooked up left & right channels together but it can act funky just because theres only one hooked up too. If both channels are hooked together, it probably burned up one of the channels in the unit. Check the balance control, with only one it may be causing problems. Hard to say really...

[AceX]

Like some of the others have said, bad ground is the most likely candidate...

[panhandler62]

I'll echo the ground. Sometimes we forget that no current is going to come through the power lead unless it can exit through the ground.

As a very basic answer -- that behavior indicates that the output stage of the amplifier is overheating. This can be caused by several things:

• Location of unit is not sufficiently ventilated
• Unit has a fault
• Too much load

The most common cause is the last one; too much load. This can be caused by running speakers that have very low impedance (or by running several speakers in parallel which effectively lowers impedance.)

It can also be caused by a faulty speaker that has a "partial short," again; effectively lowering total impedance.

The IC amplifier that is built into a head unit probably doesn't generate enough heat to overheat itself in the glovebox (unless you have a bunch of hoo-haa packed in around it.)

You can bench-test the speaker with a multimeter. A minimum of 4 ohms (and more likely 8) is best for the built in amps on most head units.

[chris71]

well, i stumbled across some 4 inch speakers that i had laying around from a previous project that i had totally forgotten about and hooked one up making sure the conections were good and all that. it works good now, as good it can out of one 4 in. at least i have tunes!!!!! the ground turned out to be good. i wouldnt have guessed that it was the speaker causing it. thanksfor the help guys.