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Subwoofer mind boggler by fieroville
Started on: 06-20-2015 05:47 PM
Replies: 17 (551 views)
Last post by: fieroville on 06-28-2015 07:12 PM
fieroville
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Report this Post06-20-2015 05:47 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Hey fiero family,
I purchased my 7th fiero GT last month with only 2 owners prior to me and only 29,000 original miles. this car literally is all original down to the cap, plugs, wires, hoses, brakes,etc. car is mint. The previous owner had owned it for 20 years and did nothing to it but oil changes, batteries and one set of tires.
The "performance sound" does not work. I have tried:
Plugging in a new sub speaker
New "used" amp that is said to be in working condition
new "used" factory radio (has the original working radio in it now)
Running a volt meter to the wire harness/plug at the sub/slider side connector to see if there is "signal" being sent from the slider

I am at a loss...the current original factory stereo works great minus the sub does not work. Besides the replacement amp being bad, what else could it be? In 25 years I never had a slider go bad. No wires have been hacked and everything is stock.
What can I be missing??
I have searched the forum until nauseum.
Thanks in advance

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Report this Post06-20-2015 06:14 PM Click Here to See the Profile for IMSA GTClick Here to Email IMSA GTSend a Private Message to IMSA GTEdit/Delete MessageReply w/QuoteDirect Link to This Post
See the "Ogre's Cave" on the very top of the screen for most of your electrical nightmares. Here is what he says about the dead sub:

Sub Woofer Amp, no power. (Speaker is known to be good.)
I don't have this to test fully. I've only seen parts of it. This should help narrow things down. This is for the factory installed sub amp.

Check the control in the dome light and see if it is working. That dome light isn't the most rugged thing on the planet. Put a jumper across the switch and/or the volume control terminals and see if the amp comes on.

The sub amp is fed from the Antenna power out on the main radio connector. It doesn't have a direct power connection to the rest of the car wiring harness. Check the terminal on the radio with 2 pink wires. (You need the radio on.) If you have power here then the radio and its internal power feeds are good.

If you have an aftermarket radio you likely need to alter the sub amp wiring to feed from the main power terminal on the radio. The Sub amp is normally powered by the OE radio's power antenna output. Your new radio probably won't provide enough power on that line even if it has one.

The "fix" most people are using is to clip the 2 pink wires from the main connector and tie them to the yellow power lead. Keep in mind though that this will effectively kill the power antenna pass through on the sub amp. (The antenna would stay up all the time when the key is on.) So if you are one of the people with a power antenna added or thinking of adding one then you may have to work out a little more wiring besides the sub amp power.

[This message has been edited by IMSA GT (edited 06-20-2015).]

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fieroville
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Report this Post06-20-2015 06:24 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Thanks IMSA,
the radio is factory. It has been hard for me to find any info on how to test the amp.
I searched ogre's cave and didn't find anything related to this specifically. But I will check again.
can you elaborate a little more on the testing of the slider?
thanks again...
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Report this Post06-20-2015 07:19 PM Click Here to See the Profile for sricka01Send a Private Message to sricka01Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroville:

Thanks IMSA,
the radio is factory. It has been hard for me to find any info on how to test the amp.
I searched ogre's cave and didn't find anything related to this specifically. But I will check again.
can you elaborate a little more on the testing of the slider?
thanks again...


Which factory? Please show a pic cuz we may not be talking same radio here. It could be later model "factory" from a firebird. I don't know if you are aware but if it's a later model, you have to cut the blue wire and reinsert into the red feed.
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Report this Post06-20-2015 07:29 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by sricka01:


Which factory? Please show a pic cuz we may not be talking same radio here. It could be later model "factory" from a firebird. I don't know if you are aware but if it's a later model, you have to cut the blue wire and reinsert into the red feed.


This is the factory equalizer radio that came with the car. It is dated late 1986.
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Report this Post06-20-2015 07:35 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
I wish there was a way to check the amp other than at the output wires at the sub connection or trying it in other cars. I do not have any others cars available to do so.

[This message has been edited by fieroville (edited 06-20-2015).]

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Report this Post06-21-2015 09:27 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroville:

I wish there was a way to check the amp other than at the output wires at the sub connection or trying it in other cars. I do not have any others cars available to do so.



you can wire it up to your home radio.. if you know what the amp's input wires are on that fiero amp..
As I'm sure it didn't use line level input it was speaker level (someone correct me if I'm wrong)
if it's line level... depending on what you have at home. you can test using a surround receivers zone 2 rca output.. and wire a speaker to the amp speaker leads.. and power it..
My shop manual is for my indy and in 84 there wasn't a sup so no wiring photo/drill down for it here..


and this might help


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Report this Post06-21-2015 09:32 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post

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Report this Post06-21-2015 09:33 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post

E.Furgal

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and the internals of the amp
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Report this Post06-21-2015 09:35 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post

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Report this Post06-21-2015 06:35 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
thanks guys for the quick responses. I checked the slider and its connections (grounds and alike). All good there. The radio is the factory original (dated may of 86'), so there is only one pink wire. I plugged in the new "used" amp and got nothing. We plugged in a new sub woofer and got nothing. I tested the orange wire from the secondary 2 wire harness on the right side of the radio and got 12 volts. The radio works fine. Plugged in another radio that worked in another car. Still did not work. All I can think of is the replacement amp does not work. I was told it did. I wish there was someone who worked on these amps that could repair them. As much as I know automotive/electrical, I cannot seem to figure this one with certainty that I covered all my bases to exact.
happy fathers day!

[This message has been edited by fieroville (edited 06-21-2015).]

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Report this Post06-22-2015 10:29 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroville:

thanks guys for the quick responses. I checked the slider and its connections (grounds and alike). All good there. The radio is the factory original (dated may of 86'), so there is only one pink wire. I plugged in the new "used" amp and got nothing. We plugged in a new sub woofer and got nothing. I tested the orange wire from the secondary 2 wire harness on the right side of the radio and got 12 volts. The radio works fine. Plugged in another radio that worked in another car. Still did not work. All I can think of is the replacement amp does not work. I was told it did. I wish there was someone who worked on these amps that could repair them. As much as I know automotive/electrical, I cannot seem to figure this one with certainty that I covered all my bases to exact.
happy fathers day!



The amp contains an 8 volt power regulator that supplies that voltage to the slider assembly on the overhead console. The slider is actually only a 10K variable resistor in series with a 10K fixed resistor to ground. This voltage divider feeds a variable voltage back to the amp that controls the volume of the amp. So, the audio signal is NOT fed up to the slider and back down, instead the amp is controlled by a voltage.

So start by testing this, the slider has 3 wires a white with black and a yellow that go to the amp.. and the last one is the ground,
with a volt meter set on the 12 volt dc scale, with the slider all the way up ( max volume) both wires should show 8 volts, and as you slide the slider down from max the volts on one wire will drop

also check at the amp


check power to both pink wires to turn on the amp. pin 13 and 3.
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Report this Post06-22-2015 11:26 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post
Here is the factory service manual test for the system..
I forgot I got a 87 manual from a car in junkyard...
if this helps rate me
<-----------------------------------------
sub by furgal, on Flickr

sub1 by furgal, on Flickr

sub3 by furgal, on Flickr

This one is out of focus so it reads

measure between | correct voltage | for diagnosis
_____________________________________________________
white with black 8 volts
& ground | approximately | see 1
_________________________________________________________
performance sound slider at minimum
______________________________________________________
yellow &ground |3.5-4.5volts |see 2
____________________________________________________
performance slider at max
_______________________________________________________
yellow&ground | approx. 8 volts | see2

_________________________________________________________
if all voltages are correct , check/repair yellow 303 wire (see schematic posted above in other post

1 check/repair white/black or white (302)wire see schematic

2 replace performance sound control


sub4 by furgal, on Flickr

sub5 by furgal, on Flickr

sub2 by furgal, on Flickr

[This message has been edited by E.Furgal (edited 06-22-2015).]

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fieroville
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Report this Post06-23-2015 11:56 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
thanks guys! now we have something here. for the slider test, do i leave everything hooked up as if its in working order and turn on the stereo to activate/energize the system? in nearly 25 years of owning fieros, i never had a slider break or go bad. is this a common part to go bad? i will test the slider first then work on testing the amp.
is it possible that the radio signal output portion that "activates" the amp go bad even though the radio itself works fine?
thanks again for the help guys, will report back soon..
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Report this Post06-24-2015 08:42 AM Click Here to See the Profile for Jason88NotchieClick Here to Email Jason88NotchieSend a Private Message to Jason88NotchieEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by E.Furgal:

Here is the factory service manual test for the system..
I forgot I got a 87 manual from a car in junkyard...
if this helps rate me
<


Good stuff Furgal!!
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Report this Post06-24-2015 09:32 AM Click Here to See the Profile for E.FurgalSend a Private Message to E.FurgalEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by fieroville:

thanks guys! now we have something here. for the slider test, do i leave everything hooked up as if its in working order( yes ) and turn on the stereo to activate/energize the system? in nearly 25 years of owning fieros, i never had a slider break or go bad. is this a common part to go bad? i will test the slider first then work on testing the amp.
is it possible that the radio signal output portion that "activates" the amp go bad even though the radio itself works fine?
thanks again for the help guys, will report back soon..


The amp gets turned on with the radio..
check for 12 volts at pin 3 and 13 as listed in the diagram. with the radio on.. you should have power there, if no power.. then the amp can't work . lol

The slider might not have broke but the connections with the wires might have..
do the test.. as listed..
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Report this Post06-28-2015 04:29 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by E.Furgal:


The amp gets turned on with the radio..
check for 12 volts at pin 3 and 13 as listed in the diagram. with the radio on.. you should have power there, if no power.. then the amp can't work . lol

The slider might not have broke but the connections with the wires might have..
do the test.. as listed..



Thanks furgal!
I guess what I meant by "leaving things hooked up" meaning, I thought the slider had to be "grounded" to the roof to work. How do I check the slider if its "hanging" by the harness? Do i still need to ground it for a proper reading with the volt meter ?
Also, what I meant about the radio "energizing" the system is that, is there a separate signal that goes to the amp from the radio? Meaning, can the radio work fine but the "signal to amp" portion be bad? Make sense??
I am working on it now...so any feedback would be essential.
Thanks again furgal for the manual pics!

[This message has been edited by fieroville (edited 06-28-2015).]

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Report this Post06-28-2015 07:12 PM Click Here to See the Profile for fierovilleClick Here to Email fierovilleSend a Private Message to fierovilleEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok, if I am understanding the series of tests, they are done in order. So, if I do the first test (F, table 1), and it "fails", would the rest of the tests be unnecessary? Meaning, the first diagnosis states to service radio. So if that does not work (the radio's signaling portion of the test) the rest of the system will not work and show voltage variances requested by the tests for the (slider, amp and speaker)?
my point being is I did the first test and received no signal or voltage to the connector at the amp. So does that mean that the RADIO is malfunctioning and is not sending a signal to amp? Can this portion of the radio go "bad" and still work otherwise? The radio works otherwise (tape, recieving station heard through the speakers, etc).
Furgal??? Bueller???

[This message has been edited by fieroville (edited 06-28-2015).]

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