No Sound - Kenwood Stereo

[jhendrix39350]

I have a 2006 LSV with a Kenwood KDC-MP2035. The radio played great last weekend, but now there is NO SOUND. The dashboard switches are lit (Stereo and ACC), the stereo is lit, but there is no sounds coming from the speakers.

System includes Kicker ZX700.5 and ZX 250.2 amps.

Any suggestions would be greatly appreciated!

John

[David Analog]

So if the HU is powering up, lit up, and responding to commands per the display read-out, then it would appear at first glance that the HU is fully functional.
Since you have two amplifiers with seven total channels we'll assume that 1) all speakers in the boat are powered by the external amplifiers, and 2) you are using both the front and rear RCA outputs of the HU (eliminating a pre-level fader being in the wrong position).
So that leaves the amplifiers. Check to see if the amplifiers are powering up when the HU powers up. The amplifiers should have a small status LED.
The HU gets its power via the factory harness, helm buss and dash switch. Yet the amplifiers have a different power source directly at the batteries with either a master fuse or breaker very close to the battery(s) or battery switch. Focus on this fuse/breaker.
The amplifier requires three power connections to operate. Main ground to battery. Main 12V power to battery (mentioned above). Small 12V 'On/Off' trigger that comes from the HU. Verify all three.

[jhendrix39350]

Thanks for the suggestions. Quick status update:

1. zx250.2 had NO LIGHTS: I found 1 negative wire that was not connected to the battery (zx250.2) I reconnected that. It now has a green light glowing, so I assume "all good".
2. zx700.5 - red light is blinking. No green light.
3. I cleaned all battery terminals and reattached all connections.
4. Used a multimeter to confirm volts: 12V at battery and at both amps.
5. I checked all fuses on both amps (4 total) using the multimeter. Everything checked out OK.
6. I tried to connect my iPhone direct to both amps. I think I did this correctly...using a speaker cable that has a red and white RCA connector. The wire I have has a third RCA connector (yellow) which I assume is video? Anyway, no sound played.

Am I overlooking something obvious?

Thanks again....
John

[David Analog]

Any chance of water damage?
Consult your amplifier owners manuals.
But I am guessing that any flashing light is a sign of a problem. A red light or flashing red light could indicate a protection mode, whether low voltage, thermal, or short circuit, etc. One amplifier gives you a green light so you can temporarily assume it's okay.
Initially since both amplifiers are giving you the same behavior, you would assume it is something that is common to both, like the absence of voltage or low voltage for example, but that may not be the case and both amplifiers may have different issues.
The relevant place and time to measure voltage is across both of the amplifier + & - primary terminals while under load. You could have enough voltage to start the boat and operate the HU but not enough for the amplifier operation. Different products have different turn-On/Off voltage thresholds. You must verify a full and minimum 12.0 + (up to 12.8V) volts in this case, and the same with the remote turn-on circuit. It's easy enough to create a temporary fused jumper for the amplifier remote turn-on terminal. I'm still skeptical over the voltage since both amplifiers developed a problem in the span of one week.
Since you are getting a green status indicator on the 2-channel amplifier, I would exclusively turn my diagnosis focus to that amplifier for the moment.

[David Analog]

Disconnect all speakers wires and speakers plus both RCAs. Use a temporary speaker and wire substitute of proven origin on one channel only.
When using your iphone as a test instrument to circumvent the HU, use your multimeter in the AC mode to confirm that your iphone is delivering an output signal on the RCA.
If you can't get a change in status then pull the amplifier(s) and take them to a local shop for a bench test independent of the boat.

[jhendrix39350]

OK...
1. I connected my iphone and a speaker direct to the Amp with the green light. it worked fine. there is a good chance that this amp is running the tower speakers which have never worked (bought the boat used).
2. I connected the same speaker direct to the HU. Worked fine.
3. The other amp still has red blinking light. The iphone/new speaker combo did not work and the red light continued to blink.
4. I disconnected the RCAs and all speaker connections for the "bad amp", still has a red blinking light.
5. I disconnected the positive cable from the "circuit breaker" and direct connected to the battery. Still a blinking red light...

I assume this means the amp is not working?

Let me know you have any other tricks?

Otherwise, I will disconnect the amp and take to a service center.

Many thanks,
John

[David Analog]

At this point take the same process-of-elimination approach with the 700 amp as you did with the 250 amp.
I'm not sure, but because the 700 is a hybrid with a Class D mono-channel and a Class AB 4-channel, and both have independent power supplies, you might be able to diagnose the two sections independently. Just conjecture. MLA knows Kicker product.

[jonyb]

If all the speakers are disconnected, and you've removed power, then re-applied power, and it still blinks red, the amp is in protect mode. Check the impedance of all the speakers that were connected to the amp. It's possible a shorted or blown speaker caused the amp problem.

[philwsailz]

Make sure the ground wire from the ZX700.5 is connected to a battery. I have seen amps try to fire up from just the ground connection made through an RCA cable, doing exactly what you describe. Check that ground and make sure it is connected.

Phil
Kicker

[jhendrix39350]

I removed the amp and took it to a local audio store. He took it in the back and returned to say that the amp is "shot". He sold me a new Polk D5000.5 which was the only marine grade amp he had in stock.

I do not like the Polk amp. I don't like the connectors or how cumbersome they are to try to mount.

I was looking on line to fine a Kicker replacement amp, but I don't see the ZX700.5 product.

What Kicker amp would I use to replace my ZX700.5?