Please help.
My nephew has a Sony xm502z driving his 4 factory speakers and another amp driving a pair of 12 subs in the trunk. Every thing was working fine until he was driving home after dark and when he turned on his parking lights the Sony amp goes into protected mode.
I had him double check all the connections and take some readings with a multi-meter every thing seems to be in order.
I had him diconnect all the speaker wires and try again...no luck
I then had him disconect the remote wire and jump across the power to the remote...no luck
I next suggested he try a differnet ground...havn't heard back yet.
What would make the amp go into protect if the only wires hooked up are the ground and power? When he pulls the parking lamp fuse every thing works fine, including the headlights.
Please help, it's his first endevor into the car audio hobby and he's getting really bummed.
Replies (17)
ttocs on 01/21/2007 19:02:17
what kind of car? The sony amp is driving the factory speakers? How long has this system been working?
smitty on 01/21/2007 19:33:20
It's an '88 Beretta.
I gave him this system out of my truck for Christmas. I installed it for him about 3 weeks ago. It was working fine for about a week and a half then the Soundstrem MC-120 amp I gave him died. He bought the Sony amp and intalled it inplace of the SoundStream. It worked fine until he turned on the lights.
The Sony amp is driving the factory speakers in the front and a pair of aftermarket 6X9's. Not sure of the brand. The MC-120 had not worked as a 4 channel amp in years so the speakers were wired in parallel. The 502 is rated at 2 ohms so I didn't think it would be an issue.
But the killer is everything works fine when the parking lights are off.
cplkittle on 01/21/2007 20:06:40
How is the system grounded? It almost sounds like the ground is tied into the parking light wire. This wire normally rests at negative and theoretically would work as a ground until the parking lights are turned on. An amp ground should never be tied in to another wire though. The ground wire from the amp should be the same size as the power wire to the amp. The ground wire from the amp need to be grounded to a bare metal surface, and the wire needs to be less than 3 feet if possible.
The only other thing I can think of is maybe the parking light wire was accidentally tied into instead of the speaker wire.
Try this first. Unplug everything from the amplifier except for the power and ground, and test it that way. Add RCAs, then speakers one at a time cycling the parking lights on and off after each connection is made and let us know when the amp starts going into protect again.
smitty on 01/21/2007 21:17:45
The amps are grounded to a body structral member inside the trunk.
I called him and told him to use his volt meter to test the ground.
Using a long piece of wire he tested the voltage between the ground termanal of the amp and the (-) side of the battery.
Expecting to see 0 volts he read 12. Then when he turns on the parking lights it reads 20 volts. I'm not sure how to explain this. But it does tend to confirm a grounding problem.
During the conversation he did mention that there is a ground for the taillights near the spot where we grounded the amps. Less than 6" away. I told him to go around the trunk with his meter and try to find a spot that doesn't change voltage when the lights are turned on.
I hope we're getting somewhere.
Thanks!
cplkittle on 01/21/2007 21:28:23
Everything you have told us so far completely blows my mind.
Try what I suggested by unplugging everything from the amp and testing it one wire at a time.
smitty on 01/21/2007 21:42:32
I'll suggest that the next time I talk to him.
I wish I could be there to help him out but we live about 2 hours away.
ttocs on 01/22/2007 00:01:50
there is a dimmer wire behind the radio that is the same color(grey I think) as one of the speaker wires.
I am also willing to bet that amp is 2 ohm stereo stable(2 ohms by 4 channels), if you have it wired for 2 ohm x 2 channel I bet that is your problem.
smitty on 01/22/2007 08:02:49
Early on I was also thinking the dimmer wire was the problem but I had him check that and its ok.
The amp is 2 channel and 2 ohm stable. The old Soundstream he replaced was 4 channel and bridged.
I'm bummed that the SS MC-120 died. That was a great little amp. But I guess after about 20 years of operation it didn't owe anybody anything.
ttocs on 01/22/2007 11:55:58
if you had him check for voltage that was on or off with the lights at his speaker wire then I am out of ideas and completly confused........ I think there is something with the wiring we are missing although I do not know what it could be.
smitty on 01/22/2007 13:27:33
He emailed me this morning. He was measureing mV not V. It was 12mV then jumped to 20mV. I would have to guess the ground is ok.
cplkittle on 01/22/2007 15:21:42
He should be measuring ohms to check for a good ground.
smitty on 01/22/2007 16:06:19
I was having him check for volts because we suspected a short in the parking lights circuit.
What value in ohms do you consider a good ground?
swez on 01/22/2007 16:33:33
With the power lead disconnected from the amp, the ground to grounding lug, ohmic reading should be virtually 'ZERO' ohms.
Also, grounding to bare metal in the floor pan, is always a good grounding strategy. (Hinges, trunk lips and other trunk metal locations can be problematic under high current loads.)
One thing I have not seen in this post.... where did he tap his +12 volts for power this amp? The common practice is a power feed line, right to the Pos Battery terminal with an inline fuse close to the Battery connection. (12-18" away) Is it possible that he tapped into his fuse panel or some other location, to feed this amp? (This could explain everything)
Comments?
Swez
smitty on 01/22/2007 19:12:06
I'll call him tonite and see if he found out anything else. The +12 is hooked up exactly as you suggest.
smitty on 01/22/2007 22:56:49
Well, he called tonight and it looks as if he has a short in the right side speaker wiring somewhere. I guess he didn't have the speaker wires as disconnected as he thought. When he disconnects the right speeker wires from the amp it works fine with or without the lights on.
Not sure how the parking lights and the right speaker wires are related, we'll see what happens after he if he finds the short.
Thanks from both of us. I post more results as soon as I know them.
swez on 01/23/2007 13:35:04
This happens at times if the rear speaker cables and tail lights are in the same wiring channel/duct and the insulation is nicked or damaged by a wayward trim screw.
The same thing will be noted if the speaker coil is shorted out or sloppy wiring at the amp. If there are any tiny "hair" wires exposed at the amp output lugs, it can cause a short there too. I have seen some very sloppy wiring from others and after cleaning things up for them, everything worked out fine.
Swez
smitty on 01/24/2007 22:30:18
All is well with the universe again. Everything is in working order. He ran new wires to the 6X9's and it it all works nicely.
Thanks for your help!!!
My nephew has a Sony xm502z driving his 4 factory speakers and another amp driving a pair of 12 subs in the trunk. Every thing was working fine until he was driving home after dark and when he turned on his parking lights the Sony amp goes into protected mode.
I had him double check all the connections and take some readings with a multi-meter every thing seems to be in order.
I had him diconnect all the speaker wires and try again...no luck
I then had him disconect the remote wire and jump across the power to the remote...no luck
I next suggested he try a differnet ground...havn't heard back yet.
What would make the amp go into protect if the only wires hooked up are the ground and power? When he pulls the parking lamp fuse every thing works fine, including the headlights.
Please help, it's his first endevor into the car audio hobby and he's getting really bummed.
Replies (17)
ttocs on 01/21/2007 19:02:17
what kind of car? The sony amp is driving the factory speakers? How long has this system been working?
smitty on 01/21/2007 19:33:20
It's an '88 Beretta.
I gave him this system out of my truck for Christmas. I installed it for him about 3 weeks ago. It was working fine for about a week and a half then the Soundstrem MC-120 amp I gave him died. He bought the Sony amp and intalled it inplace of the SoundStream. It worked fine until he turned on the lights.
The Sony amp is driving the factory speakers in the front and a pair of aftermarket 6X9's. Not sure of the brand. The MC-120 had not worked as a 4 channel amp in years so the speakers were wired in parallel. The 502 is rated at 2 ohms so I didn't think it would be an issue.
But the killer is everything works fine when the parking lights are off.
cplkittle on 01/21/2007 20:06:40
How is the system grounded? It almost sounds like the ground is tied into the parking light wire. This wire normally rests at negative and theoretically would work as a ground until the parking lights are turned on. An amp ground should never be tied in to another wire though. The ground wire from the amp should be the same size as the power wire to the amp. The ground wire from the amp need to be grounded to a bare metal surface, and the wire needs to be less than 3 feet if possible.
The only other thing I can think of is maybe the parking light wire was accidentally tied into instead of the speaker wire.
Try this first. Unplug everything from the amplifier except for the power and ground, and test it that way. Add RCAs, then speakers one at a time cycling the parking lights on and off after each connection is made and let us know when the amp starts going into protect again.
smitty on 01/21/2007 21:17:45
The amps are grounded to a body structral member inside the trunk.
I called him and told him to use his volt meter to test the ground.
Using a long piece of wire he tested the voltage between the ground termanal of the amp and the (-) side of the battery.
Expecting to see 0 volts he read 12. Then when he turns on the parking lights it reads 20 volts. I'm not sure how to explain this. But it does tend to confirm a grounding problem.
During the conversation he did mention that there is a ground for the taillights near the spot where we grounded the amps. Less than 6" away. I told him to go around the trunk with his meter and try to find a spot that doesn't change voltage when the lights are turned on.
I hope we're getting somewhere.
Thanks!
cplkittle on 01/21/2007 21:28:23
Everything you have told us so far completely blows my mind.
Try what I suggested by unplugging everything from the amp and testing it one wire at a time.
smitty on 01/21/2007 21:42:32
I'll suggest that the next time I talk to him.
I wish I could be there to help him out but we live about 2 hours away.
ttocs on 01/22/2007 00:01:50
there is a dimmer wire behind the radio that is the same color(grey I think) as one of the speaker wires.
I am also willing to bet that amp is 2 ohm stereo stable(2 ohms by 4 channels), if you have it wired for 2 ohm x 2 channel I bet that is your problem.
smitty on 01/22/2007 08:02:49
Early on I was also thinking the dimmer wire was the problem but I had him check that and its ok.
The amp is 2 channel and 2 ohm stable. The old Soundstream he replaced was 4 channel and bridged.
I'm bummed that the SS MC-120 died. That was a great little amp. But I guess after about 20 years of operation it didn't owe anybody anything.
ttocs on 01/22/2007 11:55:58
if you had him check for voltage that was on or off with the lights at his speaker wire then I am out of ideas and completly confused........ I think there is something with the wiring we are missing although I do not know what it could be.
smitty on 01/22/2007 13:27:33
He emailed me this morning. He was measureing mV not V. It was 12mV then jumped to 20mV. I would have to guess the ground is ok.
cplkittle on 01/22/2007 15:21:42
He should be measuring ohms to check for a good ground.
smitty on 01/22/2007 16:06:19
I was having him check for volts because we suspected a short in the parking lights circuit.
What value in ohms do you consider a good ground?
swez on 01/22/2007 16:33:33
With the power lead disconnected from the amp, the ground to grounding lug, ohmic reading should be virtually 'ZERO' ohms.
Also, grounding to bare metal in the floor pan, is always a good grounding strategy. (Hinges, trunk lips and other trunk metal locations can be problematic under high current loads.)
One thing I have not seen in this post.... where did he tap his +12 volts for power this amp? The common practice is a power feed line, right to the Pos Battery terminal with an inline fuse close to the Battery connection. (12-18" away) Is it possible that he tapped into his fuse panel or some other location, to feed this amp? (This could explain everything)
Comments?
Swez
smitty on 01/22/2007 19:12:06
I'll call him tonite and see if he found out anything else. The +12 is hooked up exactly as you suggest.
smitty on 01/22/2007 22:56:49
Well, he called tonight and it looks as if he has a short in the right side speaker wiring somewhere. I guess he didn't have the speaker wires as disconnected as he thought. When he disconnects the right speeker wires from the amp it works fine with or without the lights on.
Not sure how the parking lights and the right speaker wires are related, we'll see what happens after he if he finds the short.
Thanks from both of us. I post more results as soon as I know them.
swez on 01/23/2007 13:35:04
This happens at times if the rear speaker cables and tail lights are in the same wiring channel/duct and the insulation is nicked or damaged by a wayward trim screw.
The same thing will be noted if the speaker coil is shorted out or sloppy wiring at the amp. If there are any tiny "hair" wires exposed at the amp output lugs, it can cause a short there too. I have seen some very sloppy wiring from others and after cleaning things up for them, everything worked out fine.
Swez
smitty on 01/24/2007 22:30:18
All is well with the universe again. Everything is in working order. He ran new wires to the 6X9's and it it all works nicely.
Thanks for your help!!!
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