Sony N5000BT head unit intermittent audio cutting whilst driving not wiring related

[aqibi2000]

My old head unit was a concert which would also glitch/cut audio over bumps and this has carried over onto my Sony head unit too.

Now you will be screaming at this saying it's a bad Ground or bad 12V feed or bad IGN feed, I can assure it is not... full stop.

 

1) I have used an oscilloscope on the IGN and 12V feed lines a verified no drop below 12.8V during audio cut off therfore there is no bad connection here to these voltages.

 

2) I have connected additional ground cables to the head unit including a 10AWG wire directly to the battery terminal to rule out an intermittent ground connection.

I am a N5000BT head unit which has 4x 55W outputs.

I am using an ISO adaptor PC9-401 which uses resistors to bring down the level of the stereo output to a limited form inputs for the use with the rear amplified speakers ( I will be changing this in the future to PC9-404 since this prevents possibility of over driving the inputs of the rear amplifiers before this is suggested).

Please suggest what could be causing this.

 

It is a half rear amplified vehicle non bose.

~When the audio cuts out the head unit stays running/illuminated etc just the audio play back is muted, then when driving over more bumps it the audio returns (again indicative of a head unit issue or GND but have verified these already)

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[hispls 5,000+ posts]

I've had issues with removable face plate units before where the little connectors between the face and chasis get worn, damaged, or just don't sit tight anymore. That's my first suspicion.

 

[aqibi2000]

I've had issues with removable face plate units before where the little connectors between the face and chasis get worn, damaged, or just don't sit tight anymore. That's my first suspicion.

Thanks for the reply my reason for saying this isn't the cause is the fact it would happen on the audi concert head unit which didn't have a removable face plate plus this Sony headunit is just 2-3 month old. Nontheless I'll give it a clean

 

[hispls 5,000+ posts]

Thanks for the reply my reason for saying this isn't the cause is the fact it would happen on the audi concert head unit which didn't have a removable face plate plus this Sony headunit is just 2-3 month old. Nontheless I'll give it a clean

OK, how about loose or weak fuse to the factory HU location?

 

[aqibi2000]

OK, how about loose or weak fuse to the factory HU location?

I'm confident that there would be a visible voltage drop seen on the oscilloscope if this was the case

 

[DARKHART 10+ year member]

Sounds like you have a bad factory amplifier or you have a speaker that is shorting to ground somewhere which in turn may be shutting the factory amp outputs down. I've seen it both on various vehicles.

 

[aqibi2000]

Sounds like you have a bad factory amplifier or you have a speaker that is shorting to ground somewhere which in turn may be shutting the factory amp outputs down. I've seen it both on various vehicles.

Cheers that's a great shout. I'm going to disconnect the front speakers and see how it works then the rear amplified speakers

I'll post back later today with my findings. I'm suspecting the front right speaker being the issue.

 

[Louisiana_CRX 5,000+ posts]

If they are aftermarket speakers make sure the wire at the terminals isn't touching the body ..i always heat shrink my speaker terminals but you can wrap with tape to prevent ..

 

[aqibi2000]

Strange findings to report back:

- With Front speakers connected and the rear speakers outputs disconnected the symptoms are still the same.

- With Rear speakers connected and the front speakers disconnected there appears to be no issue.

The parts are all stock nothing after market other than this Sony head unit I'm putting in

So the issue is narrowed down to the front

 

[aqibi2000]

I know standard protocol would mean to individually connect each of the 4 front speakers (tweeter and speaker wired in parallel in audi cars) in turn to find the culprit but are there any other methods since the harness is tucked away behind the dash.

I've done the usual impedance testing to the speakers and in open circuit the measure just normal, the issue could be appearing during operation.

Or could be harness shorting to ground or wires touching together or even a failing speaker