From: kmr4@po.CWRU.edu (Keith M. Ryan ( aka. Wolphgang ))
Newsgroups: rec.audio
Subject: Re: Help!! "POP" on car stereo
Date: Tue, 6 Oct 1992 02:55:21 GMT
Organization: Case Western Reserve University, Cleveland, Ohio (USA)
NNTP-Posting-Host: 129.22.255.189

In article <11900006@hpmwema4.sr.hp.com> javiers@hpmwtd.sr.hp.com (Javier Sanchez) writes:
>
>I need troubleshooting hints to fix the following problem on my car
>stereo:
>
>Hardware:
>Eclipse 300 with two amplifiers (one for the rear speakers and the other
>for the back speakers)
>
>Problem:
>When turning on the stereo there is a very loud "pop" on the front
>speakers only, even if the volume is all the way down.  If the volume is up
>even a bit, then the "pop" continuos until the volume is turn dowm.

	Before anyone can give any clear answers, you must answer a few
questions, and try a couple of things to narrow down the field of possible
problems.

	First, what are the amplifers, speakers, any possible crossover, 
equalizers, etc you are using? Do you amplifers have turn one delays, or
not?
	How are they hooked up?

	Second, try doing a couple standard tests to help us get some idea
of your problem. ( substituted pop for thump ) As you go through these, write
them down, if you call a repair place, they'll most likely ask you similar 
questions to narrow down the cause.

	First, using a multi-meter: Measure the votage at the battery. It
should be about 12 V. If it is lower than 10 V, either you alternator or
you battery is going, better check with a mechanic.
	Check the voltage between the power input at the amplifer and where
your grounding point is. The voltage should be very close to the one at the
battery. If it is significantly lower, you are not using a true ground, first
check the chassis ground to battery ( there usually is a copper strap between
the chassis and the engine block, and the engine block and the negative bat-
tery terminal.) If those seem find, try relocating your ground. ( all compon-
ent ought to be grounded to the same point to eliminate ground loops )
	If this doesn't help, try following this form questions:

	Let's try to find where the noise is entering. Disconnect the inputs
to the front speaker amplifier, ( but not the remote ). Now, turn on the 
system: Do you still hear a thump?

	Yes: Goto case 1
	No : Goto case 2


	Case 1: The noise is being caused by either the amplifier itself, or
		possibly the speakers. It is most likely the amplifier, but 
		if you can easily, run the rear speakers with the front 
		amplifier, do so: Do you still hear a thump?

	Yes: Goto case 3	( most likely )
	No : Goto case 4	( possible, but unlikely )

	Case 2: The noise is being caused by a component upstream of 
		amplifier/component. Do you have any signal processors in 
		the path? Either a crossover, or an Eq? If so: disconnet 
		that components input connections. Do you still hear a 
		thump?		
	
	Yes: goto case 9	
	No: goto case 10

	Case 3: The amplifier is most likely the culpret of the noise. 
		Double check all wires, and connections. If they seem fine,
		It may be in need of repair. Contact the  service personal.

	Case 4: The culpret is either in the front speakers the speaker 
		wires,( very very unlikely, they usually either work, not 
		work, or constantly "crackle", they very very rarely cause 
		turn on pops ), or if you have one, a passive cross over 
		network. If you have a passive cross over network ( seperates
 		, just connect the front woofer to the amplifier without 
		the crossover. [ Do not just wire in the tweeter as the low 
		bass may destroy the tweeter. The treble will not hurt 
		the woofer, it just may not reproduce it well ] Do you hear 
		the thump through the woofer?

	Yes: goto case 5
	No: goto case 6

	Case 5: Either the speaker wires or the woofer is damaged. Hook up
		the woofers using another pair of wires. Do you still hear
		a thump?

	Yes: goto case 7
	No: goto case 8

	Case 6: The culpret is most likely the passive crossover network.
		Recheck connections, it may have to be replaced.

	Case 7: The speaker is most likely defective. Contact the service 
		personal.

	Case 8: It is most likely the speaker wire which is defective. 
		Replace.

	Case 9: This component is most likely the one causing the problem.
		Double check all connections, it may need to be repaired,
		contact sevice personal.

	Case 10: This component is not the one causing the noise, it is only
		reproducing the noise. Is there another component upstream?
		If so, disconnect its output, and repeat step 2 until you
		either find the component causing the noise, or you reach
		you head unit. IF you reach the head unit, case 11

	Case 11: Disconnect the antennea input to the headunit.
		 Do you still hear a thump?

	Yes: goto 12
	No:  goto 13

	Case 12 : The antennea is fine. Do you have any other inputs, CD
		changer or the like? If so, disconnect them from the head
		unit. Do you still hear a thump?

	Yes: goto 14
	No: goto 15

	Case 13: It is your antennea that is the culpret. Double check that
		it is properly secured, and measure that it is truley ground-
		ed. It may have to be replaced.


	Case 14: It is your head unit. Double check all connections, it
		may need to be repaired.

	Case 15: It is most likely your CD changer ( or the like ). Double
		check all connections, it may need to be repaird.

	Case 15: The culpret is most likely your CD changer ( or the like ).
		Double check all connections, it may need to be repaired.

	
	If this does not help you narrow down the culpret, please post 
your "answers". If you do narrow it down, at least you know what is most
likely causing the problems.