Curious radio problem
#1
Curious radio problem
I have the factory fitted premium sound system in my car, which has hitherto provided faultless service, but has now taken to cutting out as I drive. I can not detect any correlation between the sound cutting out/ back in and going over bumps etc or operating any other equipment. The sound never disappears for a few seconds, it is always for minutes at a time.
The strange thing is that when the sound goes, the unit still has power, as the screen still shows the station etc. I can change station/ waveband normally, but no sound. I did begin to thing maybe a fault with the amp in the boot, but weirdly, the aerial retracts when the sound cuts out, and re extends when it cuts back in, so I am thinking the problem must be in the head unit. Any ideas guys?
The strange thing is that when the sound goes, the unit still has power, as the screen still shows the station etc. I can change station/ waveband normally, but no sound. I did begin to thing maybe a fault with the amp in the boot, but weirdly, the aerial retracts when the sound cuts out, and re extends when it cuts back in, so I am thinking the problem must be in the head unit. Any ideas guys?
#2
I have the factory fitted premium sound system in my car, which has hitherto provided faultless service, but has now taken to cutting out as I drive. I can not detect any correlation between the sound cutting out/ back in and going over bumps etc or operating any other equipment. The sound never disappears for a few seconds, it is always for minutes at a time.
The strange thing is that when the sound goes, the unit still has power, as the screen still shows the station etc. I can change station/ waveband normally, but no sound. I did begin to thing maybe a fault with the amp in the boot, but weirdly, the aerial retracts when the sound cuts out, and re extends when it cuts back in, so I am thinking the problem must be in the head unit. Any ideas guys?
The strange thing is that when the sound goes, the unit still has power, as the screen still shows the station etc. I can change station/ waveband normally, but no sound. I did begin to thing maybe a fault with the amp in the boot, but weirdly, the aerial retracts when the sound cuts out, and re extends when it cuts back in, so I am thinking the problem must be in the head unit. Any ideas guys?
To be honest, unless the head unit has been refurbished, I'd suspect the normal head unit issues that require the boards being inspected and re-soldered.
I had a shop refurbish mine (Southern Electronics) and the radio has been good for several years now.
.
Last edited by al_roethlisberger; 06-02-2018 at 10:23 AM.
#3
There are 3 fuses in the premium system ( 4 points of entry ) and the fault correlation with the mast retracting at the same time points to the head unit as that is where the mast gets its command from .
The fuse # 8 / 15 amp trunk fuse box is for the antenna motor . This same fuse also powers pin 1 and 10 on the head unit . If you can read for power at the antenna motor at the point of occurrence you would not need to disrupt the power to the other point in the head and keep the system alive .
But then removing power from the antenna motor will only freeze the motor where it is so there must be a change in the provided ground inside the head unit . Some people have a bad on / off switch that can be cleaned and they are called encoders on the internet market pages . Comes in different post sizes . I have played with mine on this and is a DIY item . They are $ 2.00 US . The local cell phone repair shop personnel have the skill sets to solder / replace it but you might have to remove the front control circuit board for them .
See page 167 :
http://www.jagrepair.com/images/Auto.../jagxj1996.pdf
The fuse # 8 / 15 amp trunk fuse box is for the antenna motor . This same fuse also powers pin 1 and 10 on the head unit . If you can read for power at the antenna motor at the point of occurrence you would not need to disrupt the power to the other point in the head and keep the system alive .
But then removing power from the antenna motor will only freeze the motor where it is so there must be a change in the provided ground inside the head unit . Some people have a bad on / off switch that can be cleaned and they are called encoders on the internet market pages . Comes in different post sizes . I have played with mine on this and is a DIY item . They are $ 2.00 US . The local cell phone repair shop personnel have the skill sets to solder / replace it but you might have to remove the front control circuit board for them .
See page 167 :
http://www.jagrepair.com/images/Auto.../jagxj1996.pdf
Last edited by Lady Penelope; 06-02-2018 at 01:02 PM.
#4
Thanks Lady P.
I had reckoned my way to the same conclusion, that it must be in the head unit, but looking at the wiring diagram you provided, there is clearly a wire from the power amplifier to the antenna motor. I cant think why there would need to be such a connection, but it would seem to raise the prospect that the problem could be in the power amp, with it losing power, and cutting sound to the speakers, whilst commanding a retraction of the antenna.
What do you think?
I had reckoned my way to the same conclusion, that it must be in the head unit, but looking at the wiring diagram you provided, there is clearly a wire from the power amplifier to the antenna motor. I cant think why there would need to be such a connection, but it would seem to raise the prospect that the problem could be in the power amp, with it losing power, and cutting sound to the speakers, whilst commanding a retraction of the antenna.
What do you think?
#5
That wire appears to be the command wire to turn on the amplifier by giving it a ground . They must have unitized it as a way to do so since there is no dedicated way between the 2 . But you may have pointed to a scenario where if that wire is damaged and goes to car frame ground it would effect both the amplifier and antennae .
As to which direction the 2 would go to in the " operating / on mode " to which state of the 2 would require thinking through knowing that there would not be any power any where in the " off mode " otherwise they would have built in a battery drain .
A broken wire removing the ground may better explain your on car observations .
Someone with a group of contributors had broken down the contents of the 5 wire round connector as he installed a rear view camera unto his X300 to which I say Bravo / Well Played to him .
As to which direction the 2 would go to in the " operating / on mode " to which state of the 2 would require thinking through knowing that there would not be any power any where in the " off mode " otherwise they would have built in a battery drain .
A broken wire removing the ground may better explain your on car observations .
Someone with a group of contributors had broken down the contents of the 5 wire round connector as he installed a rear view camera unto his X300 to which I say Bravo / Well Played to him .
Last edited by Lady Penelope; 06-04-2018 at 12:36 PM.
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