McIntosh MCC404/MCC404M User Manual

Page 16

How to Replace the Fuses

If the MCC404/MCC404M produces no sound, there is no

Illumination of the Nomenclature on the Top Glass Panel,

and the power connections seem secure, one or more of the

Amplifier Fuse(s) may have failed. Under normal operating

conditions your amplifiers fuses should not fail. Failure of

a fuse is usually an indication of a problem. Replacing the

fuse, if there is problem in the amplifier, may incur a risk

of further damage. Refer to figures 11, 12 and 13.

Caution: Disconnect the Amplifier from the Vehicle Battery

( or DC Power Supply) as Potentially Dangerous

Currents exist inside the amplifier.

1. Before accessing fuses, disconnect both the positive

and negative power cables from the DC input terminals

on the left side of the amplifier using a 5/32 hex key.

2. Remove the Top Glass Panel by first removing the four

hex bolts with the supplied 3/32 hex key.

3. To remove the Top Glass Panel, attach the supplied

suction cup to the top center of the glass panel and

carefully raise it high enough to put your hand under.

Temporarily place the removed glass panel in a safe

place, remove the suction cup and save it for future

use.

4. Remove the Phillips Screws holding the End Caps on

both sides of the amplifier and lift the end caps off.

5. Remove the two Phillips screws located between the

low and high pass filter controls.

6. Remove all 12 crossover, equalizer and sensitivity

knobs.

7. Remove the Gold Faceplate Control Panel.

8. Remove the fuses with needle nose pliers, taking care

to avoid hitting the wattmeter during removal. Do not

lever the pliers against the wattmeter.

Note: To determine if the fuse has failed, examine the link

between the two fuse legs to see if it has a break in it.

9. Replace the fuse with one of the same type and rating

as unauthorized substitutions may prove hazardous to

you and the amplifier.

10. When reinserting the fuse, set it in place with the pliers,

then push it the rest of the way in with your finger to

avoid having the pliers slip and hit the circuit board.

11. Re-install the Gold Faceplate Control Panel and all 12

crossover, equalizer and sensitivity knobs.

12. Re-connect the power cables to the vehicle battery.

If the replacement fuse(s) fails again, have the amplifier

repaired at a McIntosh Service Center.

Remove Top Cover Screws

Figure 11

Remove Three Screws

Figure 12

Remove Three Screws

Figure 13

Location of the four fuses