Volume Issue on Front Speaker

[BlackVXGTS]

Have the following Alpine system installed in my wife's VS Clubsport for the last 23 years:

• 7987E Head Unit & CD Shuttle
• MRV-405 Amplifier
• DDD-R17H Front Speakers
• DDD-R69G - Rear Speakers

For some time now the driver door speaker has had a very quiet sound. If you turn the volume control up to full, it's only just audible. The other three speakers are fine.

Today, while fixing up another problem that required me to remove the door skin, I decided to do a little investigation before getting professional help. I switched the cables for the front speakers on the amplifier and the problem moved to the passenger speaker with the driver speaker now having full volume. That indicates that the front speakers and cabling from the amplifier to these speakers and the speakers themselves are both working fine.

Presumably the problem is either the head unit itself or the wiring between the head unit and the amplifier. The connections from the head unit on the amplifier are nice and tight (so tight that I couldn't get them off). In the past there has also been some issue with the cross-over cabling that I didn't quite understand, but was fixed under warranty. Any advice for me on the next steps?

 

[ephect]

To clarify, did you swap the RCA or input cables as well as the amp outputs to the speakers?

I know U said you couldn't get them off. This will rule out a dud amp channel

 

[BlackVXGTS]

No, didn't swap them because I couldn't get them off as I said. Bit of a bugger getting the amp off where it's located, so I'm not keen to do that again at the moment. Think I'll just check out the connections at the head unit end. Could still be a bit of work but at least I won't keep bumping my head on the inside of the boot!!! Thanks for your feedback.

 

[ephect]

Ha I know the pain

I guess if you can get to the back of the headunit easier than the the amp, then do it. I hate removing the console and headunit all that wiring in such a tight spot

If the amp channel is a dud it'll need to come out anyway.

 

[BlackVXGTS]

What's the best way to disconnect (tight) RCA connectors without damaging them (or the amp)?

 

[ephect]

Twist! Try rotate the connection clockwise/anticlockwise. If needed pliers, gentle grip on the plug close to the metal. Prefer pliers with an arch gap and twist it around. This should be enough to loosen and you can wiggle it free.

 

[losh1971]

I had this same issue last week. Turns out the amp was faulty. Not bad though it lasted close to 15 years.

 

[BlackVXGTS]

OK, thanks. Looks like I need to empty the boot out again, jump inside and work my magic? on the amp again. Hope my wife doesn't close the boot on me !!!

 

[BlackVXGTS]

Finally managed to get the time and motivation to pull out the head unit to check out the wiring - bugger of a job. The two screws attaching the dash centre fascia were impossibly tight even with liberal use of WD40. Finally managed to get one undone but had to drill the other and use an easy-out to remove it.

After all that, found out that there was nothing wrong with the head unit connectors. Back to the amplifier, swapped the front speaker connections around and the RH speaker worked fine but the LH one made only a little sound. What confused me the first time around was that the amp channel would work intermittently but then it stopped working completely which made diagnosis easy.

I made some enquiries about getting the amp fixed, but it seemed like the cost would be around the same as a new unit.