Wednesday, November 14, 2007 - 07:36 pm, by: Justin Wilson(Juzz51)
Ok, so I've got this really annoying problem with my car audio, and I really want to try and get a solid answer rather then trying to fix a costly problem that isn't even there.
Basically what's happening is when I start up the car my car audio is really quiet when cold, knob turned up full volume, but can barely hear any music. Also buzzing noise is there too.
If I drive the car for a good while, the sound will begin to increase in volume slightly, if it's a bright sunny day, warm, then the volume will get louder still, although never full volume.
Worse still, is if the car has been parked in the hot sun for what usually seems around 6+ hours, 50% of the time when I start up the car, the audio will be perfect and scare the absolute •••• out of me because the knob is turned all the way up and I'm getting full volume. However after about 5-10 minutes of driving as the car cools down the volume progressively gets lower and lower, until again, you can barely hear it.
Pretty sure this is a rare problem, but does anybody have any ideas? Should I just go ahead and get the radio unit fixed, or could it be a completely different problem?
Thursday, November 15, 2007 - 07:01 am, by: Matthew Sharpe(Madmatt)
I had a very similar problem with my '91 UZZ30 CD head unit, only mine was more that it would start out OK and get more random as the car warmed up. In the end it went away after the alternator was replaced.
The problem with the alternator was someone had done a bodgy rewind on it at some stage in the past, and as the car warmed up, the windings would heat up, and the glue they had used to pack the windings would melt, allowing the windings to seperate - this would cause voltage and current to fluctuate with the alternator (and thus engine) RPM.
Thursday, November 15, 2007 - 08:31 am, by: Andrew Stewart(Daboom)
it could also be a dry joint in the volume control knob. old solder can melt and solidify in a hot car, and if it happens enough time can cause a brittle joint
Tuesday, November 20, 2007 - 05:32 pm, by: Leon Wright(Techman)
Mine does the same thing. Plus missing the left channel and rear channels till things warm up.
I have replaced all the capacitors in the amp under the rear seat. So I'm thinking maybe the tape deck needs re-capping. I believe it is responsible for tuning etc.
I would think that dry joints would be possible, maybe part of the problem, but unlikely the cause. Generally you can belt something with dry joints and it works again. I have tried this technique and no amount of percussive maintenance will resolve the problem. It's a case of be patient till the thing warms up.
Tuesday, November 20, 2007 - 08:52 pm, by: Nik Peacock(Niko)
I had almost the reverse, all worked fine till everything warmed up(happend quicker on a warm day, only have warm in Tas) then volume went nuts and changed from speaker to speaker for a few seconds then sound was really tinny and volume couldn't be changed. Tracked it down to the contacts on the plugs going into the unit, if after the problem started I wobbled the plugs I could resolve the issue for a while. So what I did was remove each spade bit from the plugs and re-tension the spring contact, BUT make sure you replace the wires in the correct position unlike what I did. I also re-soldered where the pins from the plugs connect to the circuit board. After having the unit checked and given the all clear I finally worked out my cock up with the wire positions and everything has worked to perfection since
Tuesday, November 20, 2007 - 10:37 pm, by: Justin Wilson(Juzz51)
Hmmm, all sounds a little too hard for someone like me to fix myself. Anyone in Victoria willing to have a look at this for me? I'm willing to pay dollars, I've really got to get this fixed before I sell the car.
Thursday, November 22, 2007 - 11:15 am, by: Leon Wright(Techman)
Damian Ware wrote on Wednesday, November 21, 2007 - 12:39 pm:
This is becoming a more common fault with the radio units.
Is it what I suggested? Because I have all the necessary components and ability to replace them, just not the vast trouble shooting experience to figure out what is wrong.
Thursday, November 22, 2007 - 09:28 pm, by: Luke Gomer(Luke)
Component failure is the main cause of these types of faults and cost the odd $ (£) to buy - knowing which components to replace is what costs money .
Leon, don't forget the amp in the boot - this will often cause loss of a channel or even total audio failure (not bass)
I did a Vlad radio conversion yesterday - the owner had an alternator type buzz on the audio before conversion, this buzz was found to be due to someone connecting an aftermarket CD changer fm modulator controller to the radio box/DSP unit wiring.
Friday, November 23, 2007 - 09:16 am, by: Leon Wright(Techman)
Indeed. But they must have common faults!
The unit under the back seat I have had out, a fair percentage of the caps were expanding and some were leaking. So I replaced them all and repaired the affected tracks.
So I'm guessing the problem is further up the chain, as whilst it improved things it didn't solve the problem.
Wednesday, November 28, 2007 - 10:12 am, by: Leon Wright(Techman)
Well I've had the amp out of the boot, I must say every time I pull something apart it reminds of how well built these cars are! The amp is so clean and neat. A lot of bulging caps though! I have most on hand, just missing a 330, a few 3300's and a 2200. The 3300's look ok, but I like to replace all electrolytics while I have things apart.
Thursday, December 13, 2007 - 08:41 pm, by: Justin Wilson(Juzz51)
Just a quick shout out to Damian Ware, after so much suffering with this damn audio problem, Damian solved it all for me. Many thanks. If anybody has any problems with their radio unit, he is the man to speak to.
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