Kicker ZR1000 issue

[mbates14]

Kicker ZR1000 has -53v rails on both speaker outputs.


all of the output transistors are ok. both rail voltages are present on the test points, as well as both 15v rails are present as well. Amplifier IS NOT kicking into protection.

Any ideas?

[Perry Babin]

With the black meter probe on one of the non-bridging speaker terminals, do you still read negative 53v when you place the red probe on the bridging speaker terminals?

[mbates14]

found a little itty bitty SMD fuse on the bottom side of the mainboard, blown.

[Perry Babin]

It's a 1 amp fuse. The 468 Littelfuse is a good replacement.

This amp has the RCA shield connected directly to the secondary center tap of the transformer. The secondary winding is isolated from the power input ground. The isolation of the secondary is what prevents ground loop noise in this amp (when installed in a vehicle). The circuit board copper surrounding/under the screw that's located directly adjacent to the secondary center tap is not isolated. The screw makes contact with the copper and therefore it makes contact with the secondary. If you use a metallic screw in that location, you will short the secondary center tap to the heatsink. If the heatsink is grounded, you will have noise from the ground loop. A nylon screw needs to be used in that location and you need to make sure that the plastic cylinder is around the mounting boss so that the board cannot make contact with the boss.