Need help from the audio GURU's, MONO Class D amp problem.

DDonnie

Original poster
Member
Mar 26, 2012
2,631
I have an older MTX 6500D amp. When the amp is hooked up but the remote is switched off, I'm getting 2 volts at the battery wire. When I disconnect the wire from the amp, i get 12 volts. Checked the ground, it's good. Checked all 3 fuses, they are all good. Should it it be reading such low voltage or does it sound like there is a short somewhere in the amp? Keep in mind, i am diagnosing this because my amp refuses to come on. I've also checked the remote power to make sure i have 12 volts there as well.
 

MAY03LT

Member
Nov 18, 2011
3,412
It shouldn't be reading 2v, should be darn near battery voltage.

With the B+, ground, and remote leads hooked up, and with the remote lead having a 12v signal, does the LED on the front light up?
 

Black LT

Member
Dec 4, 2011
211
If your amp is hooked to the starting battery and the truck starts, you know there is 12 volts and you have a bad connection somewhere.

If you have a separate battery for the amp, it is either a bad connection or the battery is shot. Just because it shows 12v doesn't mean it's good. (the above scenario, you do know if the truck starts)
I had a battery that would show 12.6 and as soon as I try to start the truck it would go way down (I don't remember 2 - 6 - 8 whatever) and not even click. Unhook the cable and it would show 12 again!

EDIT - what he said too! I type slow!
 

DDonnie

Original poster
Member
Mar 26, 2012
2,631
MAY03LT said:
It shouldn't be reading 2v, should be darn near battery voltage.

With the B+, ground, and remote leads hooked up, and with the remote lead having a 12v signal, does the LED on the front light up?

no, it's not coming on at all.

Also, I'm running it off of the main battery. Truck is starting fine.
 

Black LT

Member
Dec 4, 2011
211
ConeKilrAutoX said:
I would say the amp power supply could be causing problems. Same thing happened to me before and thats exactly what happened.

But if the amps battery wire is coming from the starting battery, why would it show 2 volts? If you hook something to the battery to pull enough current that it shows 2 volts - it won't be long till the smoke/spark show. (like immediately)
I'm not saying it's not the amps power supply - I'm just saying that a wire coming directly from the battery can't only have 2 volts and start the truck.

Where is your ground?

You're checking the voltage at the amps 2 power wires?
Try checking with the amps + and a different ground (not the amps ground wire)
Check the wire connections going into and out of the fuse holders.
 

MAY03LT

Member
Nov 18, 2011
3,412
I forgot those don't have a protect indicator, just the LED goes out when something aint right. So it might be going into protect as soon as it sees power.
 

djez015

Member
Jan 28, 2013
67
are you running a cap??
 

DDonnie

Original poster
Member
Mar 26, 2012
2,631
No cap. When I pull the wire off the amp it shows 12v. The ground is good, I tested that using the 12v post at the fuse box. I am grounding at the factory ground behind the passenger rear brake lamp.

Also, I checked it using the ground underneath the fuse box, same results.
 

DDonnie

Original poster
Member
Mar 26, 2012
2,631
ConeKilrAutoX said:
I would say the amp power supply could be causing problems. Same thing happened to me before and thats exactly what happened.

Can this be fixed or am I better off getting a new amp with the age of this one?
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
dcmtnbkr said:
Can this be fixed or am I better off getting a new amp with the age of this one?

I got a quote for a new power supply in the pioneer for almost 2/3 of the cost of a new amp so I just decided to buy a new one because I didnt want to risk the money for a repair and if so how long would it have worked before what caused the incident in the first place to happen again?

I was only thinking power supply because I ran a direct battery line showing 12v with the car off and the accessory on and running it would show like 13.5 on my cap unless bass dropped with the car on and wouldnt go below 11.8 for more than a second. but 8 months later I was only getting 3v with car on and less than 3v on accessory and when I tested my grounds and and my power line and everything tested out fine (Cap was fine also because I tested it on 3 other peoples systems + other peoples amps worked on my wiring) My fail warning light did go on occasionally but other times it didnt light up and still had the same lousy reading of small voltage. The mofset power supply I had in the amp had failed it was determined by Pioneer.

do you have another persons amp you can use to test if its the wiring ?
 

DDonnie

Original poster
Member
Mar 26, 2012
2,631
ConeKilrAutoX said:
I got a quote for a new power supply in the pioneer for almost 2/3 of the cost of a new amp so I just decided to buy a new one because I didnt want to risk the money for a repair and if so how long would it have worked before what caused the incident in the first place to happen again?

I was only thinking power supply because I ran a direct battery line showing 12v with the car off and the accessory on and running it would show like 13.5 on my cap unless bass dropped with the car on and wouldnt go below 11.8 for more than a second. but 8 months later I was only getting 3v with car on and less than 3v on accessory and when I tested my grounds and and my power line and everything tested out fine (Cap was fine also because I tested it on 3 other peoples systems + other peoples amps worked on my wiring) My fail warning light did go on occasionally but other times it didnt light up and still had the same lousy reading of small voltage. The mofset power supply I had in the amp had failed it was determined by Pioneer.

do you have another persons amp you can use to test if its the wiring ?

Gonna hopefully try that tomorrow. Upon further investigation though, my wife "May have" (according to her) dropped my amp from the top shelf of our closet when i had taken my subs out a few months ago. :hissyfit:
 

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