My 23 year old son just picked up a used Memphis subwoofer box with a Memphis 16-MC500D amp. We removed the amp and speaker from the old car and installed in his new car.
We hooked the power wires up in this order at the amplifier terminals.
First: Ground
Second: +12V. Upon applying the 12V there was a brief spark at the terminal and the PROT LED lit for about a 1/2 second then went off.
Third: Remote line from the head unit.
Upon powering the head unit, the amp PROT LED lit for about 1/2 second then went off. The amp will not power on. The green POWER LED never lights up.
Checking the terminal voltages, we find that they appear OK.
+12V line: 12.57V
GND: Ground
REMOTE: 11.55V
We shut down the head unit and removed REMOTE POWER and +12V from the terminals.
We flipped the amp upside down and saw there were 25 Amp fuses installed.
I pulled and checked the fuses (both tested OK.)
I reapplied +12V and REMOTE POWER to the amp terminals. (Fuses uninstalled)
With the bottom fuse out of the circuit - the FUSE FAULT LED lit up and stayed lit until I put the fuse back in. The top fuse in or out had no impact on the FUSE FAULT LED.
So with the fuses in, each time we power the head unit on, the amp PROT LED lights for about 1/2 second then turns off. The amp never powers on. The green POWER LED never lights up.
This is repeatable.
Since I don't have a service manual, I've not started internal troubleshooting yet. I have a few questions that I need answered so I can have a baseline to start with.
Q1: What are the standard fuses that should be used? I saw another post that mentioned 10 Amp fuses.
Q2: Being that there were 25 Amp fuses installed in the amp, would that have allowed some internal damage when connecting +12V?
Q3: Should one expect a 1/2 volt drop on the REMOTE terminal with the head unit on? I don't know what the expected drain current should be at the REMOTE POWER terminal when turned on, so I don't know what if any I * R drop there should be.
Q4: Has anybody seen the symptom before such that the PROT LED lights for 1/2 second then nothing else happens?
Thanks in advance,
George
We hooked the power wires up in this order at the amplifier terminals.
First: Ground
Second: +12V. Upon applying the 12V there was a brief spark at the terminal and the PROT LED lit for about a 1/2 second then went off.
Third: Remote line from the head unit.
Upon powering the head unit, the amp PROT LED lit for about 1/2 second then went off. The amp will not power on. The green POWER LED never lights up.
Checking the terminal voltages, we find that they appear OK.
+12V line: 12.57V
GND: Ground
REMOTE: 11.55V
We shut down the head unit and removed REMOTE POWER and +12V from the terminals.
We flipped the amp upside down and saw there were 25 Amp fuses installed.
I pulled and checked the fuses (both tested OK.)
I reapplied +12V and REMOTE POWER to the amp terminals. (Fuses uninstalled)
With the bottom fuse out of the circuit - the FUSE FAULT LED lit up and stayed lit until I put the fuse back in. The top fuse in or out had no impact on the FUSE FAULT LED.
So with the fuses in, each time we power the head unit on, the amp PROT LED lights for about 1/2 second then turns off. The amp never powers on. The green POWER LED never lights up.
This is repeatable.
Since I don't have a service manual, I've not started internal troubleshooting yet. I have a few questions that I need answered so I can have a baseline to start with.
Q1: What are the standard fuses that should be used? I saw another post that mentioned 10 Amp fuses.
Q2: Being that there were 25 Amp fuses installed in the amp, would that have allowed some internal damage when connecting +12V?
Q3: Should one expect a 1/2 volt drop on the REMOTE terminal with the head unit on? I don't know what the expected drain current should be at the REMOTE POWER terminal when turned on, so I don't know what if any I * R drop there should be.
Q4: Has anybody seen the symptom before such that the PROT LED lights for 1/2 second then nothing else happens?
Thanks in advance,
George
these amps have common issues with the leds breaking off...do the relay in the amp click after a few seconds of the amp being powered on?
Reply to thread Re: Memphis 16-MC500D troubleshooting help needed
Hi Theoddguy,
No the relay does nothing. Once the PROT LED comes on and goes off nothing happens. It is completely quiet.
Hi Theoddguy,
No the relay does nothing. Once the PROT LED comes on and goes off nothing happens. It is completely quiet.
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