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Today at Atelier Kaz - Private NSX Enthusiast, ex-Honda R&D engineer with F1, Indy/CART background

Audio Head Unit Service 01

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Another audio head unit was sent in from the owner stating that after parking the car for several days, the display of the audio head unit blacked out but still being able to listen to the music although none of the 8 switches on the front panel worked.
Switching on and off the unit several times seem to fix the issue and all switches now works fine.
It was frequent but not consistent issue so somewhat not an easy task to reproduce the same issue on the bench.

So, before opening the unit, I spent a few days just to recreate the same issue under all sorts of conditions such as different temperature, length of time operating the unit, illumination on/off, with/without the backup power supply, etc and none of them had any effects and the head unit just simply operated fine in all three modes, the radio, the cassette and the CD.

All the time, the display was fine and all 8 switches responded if any features were applied in that specific mode.

My initial thoughts when I first heard his issue, I was under the impression that somehow that flex circuit board from the front panel got loose at the connector located on the centre main board inside the unit and causing intermittent continuity but after spending days with the unit, I didn’t think that was the case.

As I couldn’t recreate the same issue and already spent several days, contacted the owner to explain the situation and we decided to go ahead with opening the unit and carry out the standard service.








As soon as I opened the unit, the first thing I noticed was some sort of oil like fluid covering the edge of the board as well as part of the side wall of the unit case.
Possibly someone sprayed the contact cleaner or similar products in the past but the amount and the area covered were just excessive and it’s not something you can do without opening the unit.




It’s the later spec board and no trace of modification after leaving the factory so not sure why the unit was opened.

Only minimum leakage from the big capacitors so fairly easy service apart from not being able to recreate the display board issue.
The flex circuit board was fully inserted and locked to the centre main board so intermittent connection was not observed. As far as I can see, the flex circuit itself was not overly bent so again, no issues there.




Power I/F board refurbished.




Standard procedure of reinforcing the ACC line although the owner still using the CD changer and not the iPod adaptor.




Removed the volume pot and applied the contact cleaner.




All caps replaced and quick brushing of conformal coating at the back side especially around the additional wire.









Initial bench testing with all three modes.



So, everything works as they should and now time for the display check.
Kept running the head unit for hours without changing anything, switched on and off the unit frequently like every 5 - 10min, switched off the unit but kept the backup power overnight, etc, etc and still everything worked fine, same as before opening the head unit for the service.

After speaking to the owner bit more in detail, apparently, he feels that the issue tends to happen after parking the car for about 4 – 5 days with the battery disconnected so although there was no way for the head unit to recognise how long it was powered down, kept the unit without the backup power for 5 days and then carried out all sorts of testing again and still no issues.

At this point, I came to a conclusion that whatever the reason, I won’t be able to create the same issue on my bench so asked the owner to try this refurbished unit on his NSX with the connector fully locked on installation.


Hope it’s something outside of the head unit although very unlikely……


Kaz



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