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old Alpine 7903M headunit problems
old Alpine 7903M headunit problems
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Old 7th September 2011, 05:57 PM   #1
Kei is offline Kei  Wales
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Default old Alpine 7903M headunit problems

My 7903 will not read discs for some bizzare reason. I have looked through this thread about another user with what sounds like the same issue. Since i already owned a functioning 7915M aswell (which has been in bits before) i knew that the cd-mech was virtually identical.

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This was the only difference, so i swapped the boards over.
Click the image to open in full size.

Now on testing the 7903, it loads the disc in fine and spins it. The laser assembly moves from the inner track right out to the edge and stops where it then decides to park and eject the disc. (i don't think the laser is emitting either) The laser assembly doesn't move back and if i reinsert the disc it doesn't even spin. I rebuilt the 7915 with the cd-mech from the 7903, just to test it and it actually works fine, better than the original too. This leads me to believe that there is something up with the laser control circuitry, however i am at a loss as to what.

The unit also has an aux in to allow a second alpine headunit to be connected however if i plug a device in the output is very quiet. If i increase the amplification on the input it will distort.

I've been having issues with various old alpine units as you can see by the collection. The 7385R has a dead preamp, the 7903M won't play cd's (nor line in) and the 7915M has an intermittent remote/antenna signal. The 7915 is the current workhorse with a separate amp-on switch.
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Old 7th September 2011, 07:23 PM   #2
Kei is offline Kei  Wales
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Just noticed that if i shut off my bench supply to the headunit with the aux input still playing through, the volume jumps up to what it should be. The fade control seems to function on the aux to. I've tried applying +12v to the audio interrupt in and the brown/white wire (which pauses playback) to no avail.
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Old 16th August 2015, 04:37 AM   #3
Studio1 is offline Studio1  New Zealand
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Hi Kei, did you manage to sort the problems with your units?
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Old 16th August 2015, 08:53 AM   #4
Kei is offline Kei  Wales
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Fixed the issues with the 7915 and the 7385. Both were caused by capacitors that had seriously passed their best.

Tried my best with the 7903 but never got it going. Just refused to do anything with a cd when it was inserted. Didn't even attempt to read it, sat there for 5 seconds or so and then ejected it again.
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Old 13th September 2018, 08:30 PM   #5
MrFosgate is offline MrFosgate
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Quote:
Originally Posted by Kei View Post
Fixed the issues with the 7915 and the 7385. Both were caused by capacitors that had seriously passed their best.

Tried my best with the 7903 but never got it going. Just refused to do anything with a cd when it was inserted. Didn't even attempt to read it, sat there for 5 seconds or so and then ejected it again.

Yes its an old thread;

did you ever get the aux in to work at normal volume on the 7915?
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Old 28th September 2018, 07:59 AM   #6
Kei is offline Kei  Wales
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I ditched all my old alpine units in the end as they lacked too many features to make them useful. Went down the clarion DRX-9255 route for a few years before finally giving up on old head units due to reliability issues and no modern features. I’ve got a modern alpine cda-137bti now which seems to sound equally as good as any of the older units did with all the modern benefits of reliability and plenty of connectivity.

As to the aux in, it was on the 7903 not the 7915 and no, sadly I never did get it to work the way I wanted it to as it was designed as a master/slave system for running two head units together. I recall there being empty sections on the pcb in the 7915 labelled aux in with 7915J next to them suggesting a JDM version of the unit existed with an auxiliary input but without knowing what components are missing, it’s virtually impossible to retrofit it. If I can find them, I’ll try and post up some pictures I took of the inside of my 7915 back when I repaired it.
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Last edited by Kei; 28th September 2018 at 08:01 AM.
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Old 28th September 2018, 11:21 AM   #7
Studio1 is offline Studio1  New Zealand
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It's a shame you weren't able to sort them, an even bigger shame that you've ditched them.
I would have bought them from you. I collect the vintage Alpine stuff.
I agree that the modern units have functionality, better features etc but the reasons to own and use vintage equipment are the looks, the feel, the style and the joy of using something old that still plays (when it's working of course!)
I have spent many years now restoring and repairing vintage Alpine units.
My philosophy is that where possible, any gear I have in my collection must be in working condition.
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Old 28th September 2018, 01:43 PM   #8
Kei is offline Kei  Wales
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By ditched, I didn't mean scrapped or binned just no longer in active use. I'd never scrap something vintage unless it was completely serviceable with no bits that could be utilised for spares.

7915 pictures as promised. Looks like I remembered incorrectly and it's a 7802J that has the pre in.
old Alpine 7903M headunit problems

old Alpine 7903M headunit problems
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Old 11th June 2019, 08:56 AM   #9
Ozzyozzyozzy is offline Ozzyozzyozzy
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Default Alpine 7915 or 7803 sleeve and wiring harness

Greetings....., was wondering if you might have a sleeve and wiring harness for Alpine 7915 or 7803? Cheers Tony
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