Question about Ultra Linear UL-4400D Car Audio Amplifier
Posted by Anonymous on
SOURCE: ultra linear ul-600hc
If the amp is in protect mode, it probably has shorted output transistors. To eliminate other possible problems, do the following. I'll assume that you've checked the amplifier's on-board fuses.
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 the voltage remains near or above 12v, disconnect all speaker wires from the speaker terminals of the amp and disconnect signal cables from the amp. If it powers up, the wiring needs to be checked. If it still shuts down, the amp almost certainly has shorted output transistors and will need to be repaired.
Let me know if you have any other questions.
Posted on Aug 26, 2008
YOUR METHOD OF TROUBLESHOOTING USING THE PROCESS OF ELIMINATION IS RIGHT ON AND PERFECT. IT INDICATES A BAD AMPLIFIER CHANNEL. I KNOW THIS SOUNDS ODD, AS YOU HAVE TWO OF THESE NOW. IT IS RARE, BUT I HAVE SEEN INPUT CONFIGURATION SWITCHES WIRED BACKWARDS, SO THE ONLY THING LEFT TO DO IS TO HOOK UP THE BAD CHANNEL TO ONE SPEAKER ONLY, BY ITSELF. THEN TAKE ONE RCA ONLY AND PLUG IT INTO ONE RCA INPUT AT A TIME. THEN MOVE THE INPUT SWITCHES AND REPEAT THIS PROCEDURE UNTIL YOU HAVE TRIED ALL SWITCH COMBINATIONS AND ALL INPUT JACKS. WHAT YOU ARE TRYING TO DO AT THIS POINT IS TO DETERMINE IF THERE IS ANY RCA JACK WITH ANY SWITCH POSITION, THAT WILL ALLOW YOU TO GET OUTPUT FROM THAT CHANNEL. IF AFTER THIS TEST, YOU STILL HAVE NO OUTPUT, THEN NO MATTER HOW ODD, IT WOULD INDICATE THAT YOU DO IN FACT HAVE A SECOND DEFECTIVE AMPLIFIER. LET ME KNOW IF YOU NEED FURTHER ASSISTANCE.....V
Posted on Jan 06, 2010
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