Hi I amconnecting r300-4 rockford ampp at home as a test before installing in my car. I have connected 12v dc adapter but the amp's red led glows and amp turn off. Any solution

When the mouse chewed through, it joined the two wires together so has probably shorted something out. Look inside for a PCB mounted fuse.

Hi Bob

Not much info to go on??

Usually don't need one
12v DC to posative (red)
12v Ground to Chassis or body of Amp
Possibly an Ignition Key 12v to hold memory settings
2 Speaker Unit will have 4 wires - 2 to each speaker
one wire of each pair will have a stripe (say negative)
keep striped wire to same speaker terminals to keep the speakers in phase with each other (speaker cones travel in same direction or you get distortion)
4 Speaker Unit - same as above but either Front Pair or Rear Pair.

Get the Amp on a bench & test the unit with a couple of cheap temporary speakers.

Good Luck
How to connect your car amplifier very simple explination and test

Part 1 How To Set Up PSU Car Amp Subwoofer In Home Re Do Video

RED +12V
BLACK -12V
YELLOW +VIDEO
WHITE - VIDEO

DC Jack diagnosis:
1. Test power adapter for output voltage. Bend the power cable in various directions while doing this to be sure that there is no broken conductors in the cable.
2. If power adapter is Ok, connect it & see if the power LED on the laptop will glow when you jiggle the power connector in various directions. If yes, then the DC jack might be loose or damaged, & need to be either re-soldered or replaced.
3. If not, then disassemble the laptop. Remove any components that attach to the laptop's motherboard first (e.g. battery, hard drive, RAM, wireless card, optical drive, ... etc.)
4. Next, remove the keyboard & the LCD screen.
5. Finally, unscrew all screws that hold the upper cover & lower cover together so that you could gain access to the motherboard.
6. Inspect the solder points connecting the DC jack to the motherboard. Make sure that none of them is loose. If any, re-solder them.
7. Inspect the center pin in the DC jack. Make sure that it is not broken or loose. If it is, then you might need to replace the DC jack.
8. When you are done, re-assemble back the laptop.

1. Test power adapter for output voltage. Bend the power cable in various directions while doing this to be sure that there is no broken conductors in the cable.
2. If power adapter is Ok, connect it & see if the power LED on the laptop will glow when you jiggle the power connector in various directions. If yes, then the DC jack might be loose or damaged, & need to be either re-soldered or replaced.
3. If not, then disassemble the laptop. Remove any components that attach to the laptop's motherboard first (e.g. battery, hard drive, RAM, wireless card, optical drive, ... etc.)
4. Next, remove the keyboard & the LCD screen.
5. Finally, unscrew all screws that hold the upper cover & lower cover together so that you could gain access to the motherboard.
6. Inspect the solder points connecting the DC jack to the motherboard. Make sure that none of them is loose. If any, re-solder them.
7. Inspect the center pin in the DC jack. Make sure that it is not broken or loose. If it is, then you might need to replace the DC jack.
8. When you are done, re-assemble back the laptop.

You should verify some other way (with a multimeter or another amp/device) that your 12V is working at the amp. Then to troubleshoot the Remote wire, take a short lead of scrap wire and run it from the 12V power input of the amp over to the Remote input like a jumper. If the amp still doesn't power up, then look for and check the fuse on the amp. If there's good power at the amp, the remote input has good power, and the amp doesn't turn on, and the fuse isn't blown, then the amp is probably toast. Good luck!

if it is led it most likely is a low volt and very low amps. you can go behind the radio and find the switched wire using a test light when you turn on car the test light will light you want to use this wire and splice it in using the blue scissor type splicers no cutting or soldering required. This wire will be close to the black and red wire going into radio. Possibly a red wire as well if there are two red wires one might be switched and one always on for retaining clock or radio stations in memory.

There is no reset button on the amp.

With your multimeter set to DC volts, the black meter lead on the ground terminal of the amp (not on the point where the ground wire connected to the vehicle) and the head unit on (so the amp will have remote voltage applied), touch the red lead alternately to the B+ and remote terminals of the amp. If the voltage is below ~11 volts, you need to check the wiring feeding whichever line is too low. If both are above 12v, the amp will require servicing.

you should connect it to the 12v positive of the power supply, maybe install a switch in line between the amp and power supply.

If you have another amp in the vehicle, swap the RCAs and speakers to see if you get sound through the other amp.

Generally, if the red light is on and there is no significant DC on the speaker terminals, the amp is in good working order (for the older Rockford amps).