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View Full Version : How do I figure out why an AMP has gone to protected mode



bkearney
04-30-2012, 09:11 AM
In installed an amp a month ago (JL JK360) and it worked fine the first 2 times on the water. This weekend, I turned it on.. and it immediality went into protected mode. Looking at the manual I see:

"Protect” (Red): Indicates that the amplifier
protection circuitry has been activated
to prevent product failure due to thermal
overload, short-circuit or a dangerously
low impedance connected to the amplifier
outputs. Connecting the speaker outputs
to an impedance lower than 2 ohms stereo
(4 ohms bridged) will cause this protection
mode to activate. When this protection mode
is activated, the amplifier will shut down to
protect its circuitry. When the problem is
corrected, the amplifier will return to normal
operation and the “Protect” LED will shut off.
"

How do I go about fifguring out the issue? Is it disconnecting the speakers? Are there other places to look?

Thanks in advance.

sandm
04-30-2012, 09:59 AM
check speaker wiring at the amp and at the speaker.
check ground wire and make sure it's solid.

that's where i'd start if it was me.
it would be easier to start at the amp than each speaker so i'd choose that location first, then if it's not fixed, check each speaker for shorts or some wires touching.

Dubwake21
04-30-2012, 11:03 AM
The ground is usually the problem. Make sure that you have a common ground for all of the right parts as well.

mmandley
04-30-2012, 12:10 PM
In installed an amp a month ago (JL JK360) and it worked fine the first 2 times on the water. This weekend, I turned it on.. and it immediality went into protected mode. Looking at the manual I see:

"Protect” (Red): Indicates that the amplifier
protection circuitry has been activated
to prevent product failure due to thermal
overload, short-circuit or a dangerously
low impedance connected to the amplifier
outputs. Connecting the speaker outputs
to an impedance lower than 2 ohms stereo
(4 ohms bridged) will cause this protection
mode to activate. When this protection mode
is activated, the amplifier will shut down to
protect its circuitry. When the problem is
corrected, the amplifier will return to normal
operation and the “Protect” LED will shut off.
"

How do I go about fifguring out the issue? Is it disconnecting the speakers? Are there other places to look?

Thanks in advance.

If everything worked fine and now it doesnt then this is the route id use to check my problem.

1. Make sure the batteries are completly charged.
2. Make sure all your connections are tight at the amp

For all connecting and disconnecting i reccomend you turn off the Deck to prevent shorting.

3. Unplug both RCAs into the amp, if amp works then you have bad RCA or the Deck output has an internal short.

Problem still there proceed.
Replug in the RCAs.
4. Unplug each speaker pluged into the amp and see if the amp will power back up after each are unpluged.
If at any time you unplug a speaker and the amp comes back on then you know what speaker leg is causing the problem.
To check that leg plug that speaker into another amp channel, if the amp goes back into protect, then that speaker leg is they problem, if the amp DOES NOT go into protect then that amp has a bad channel where that speaker was opriginally connected.

If the amp has continuously stayed in protect mode and the only thing pluged in is power at this point, then the amp has an internal problem.

As for the speaker leg, if its showing bad then you will need to check all connections in that leg, if its connected to other speakers, or just the connections on the speaker its self. If you swap the speaker and still get this problem then most likley the speaker wire has grounded out on something. Time to replace the wire.

kaneboats
04-30-2012, 01:36 PM
Good stuff, Mike. Great help.

bkearney
04-30-2012, 01:40 PM
Thanks for the info. Now I know what I am doing tonite!

bkearney
05-01-2012, 09:32 AM
OK.. that was the trick. Thank you! The ground wire came disconnected. I used a crimp connection. I may need to upgrade to a solder pellet. So, why would this cause the amp to go into protect? I would have assumed with no ground that there would be no power.

EarmarkMarine
05-01-2012, 10:59 AM
Low voltage is one reason. A microprocessor (protection circuitry) without a good ground could do most anything without predictability.

philwsailz
05-01-2012, 03:45 PM
OK.. that was the trick. Thank you! The ground wire came disconnected. I used a crimp connection. I may need to upgrade to a solder pellet. So, why would this cause the amp to go into protect? I would have assumed with no ground that there would be no power.
You can show an amp a ground potential through the shield of your RCA cable, but it can't carry enough current to get the thing to turn on. Hence, protect.

Phil
Kicker

chawk610
05-02-2012, 08:06 AM
started new thread...