What size fuse in a clarion apx2120 120watt amp

I have no idea. Recommend contacting a local car audio professional or Clarion customer support directly here:

https://clarion.com/xe/en/user-support/inquiry/contactus

4 Gauge would be best (100mm2) but it will work on 8 gauge.

HI,
If the fuse is blowing of then there is problem with the inverter stage of amplifier. There is an inverter stage in the amplifier to boost the 12V to + or - 30 to 40V normally. Its a switching circuit normally uses Mosfets and ferrite core transformer and a driving IC. If the mosfet is shot then the fuse will blow off immediately after power is connected.

Check on thing remove the REM connection and then connect the power. If the fuse blows the there is fault with the Mosfet Its short.
If the fuse blows only when you connect the REM then the amplifier stage is faulty.

Also check by disconnecting the speakers. if any of the speaker is faulty then there is a chance for fuse blow off.

Ajin

Do you have the Continuous power wire hooked up to the amp from the stereo? that will generally make the amp not turn on.

all the fuses including the ones behind the radio? if you tried that, try resetting the unit. there should be a little button about 2-3 mm in size either on the faceplate or behind it that can reset the system.

check for busted fuse, or else your amp needs service.

check to see if you have any grounding issues or if ground is present

Hi,

For a single Clarion APX480M, the inline fuse should have a rating of 40 amperes.

Incidentally, perhaps a copy of the installation manual would be of use to you. One is available here.

Hope this be of initial help/idea. Pls post back how things turned up or should you need additional information.

Good luck and kind regards.

Thank you for using FixYa.

Make sure your ignition signal wire didn't come loose somewhere. Was the Amp exposed to extreme heat?