Lots of Electronics 202503

[Kaz-kzukNA1]

Started servicing another NSX and focusing on the Health Check as there are few things I want to check first before taking the Eng/gbox out of the bay.

Strange wire coming out of O2 sensor ext cable, a/c refrigerant leakage that the specialist couldn't find from where, intermittent [BRAKE LAMP] warning but confirmed it was the actual lightbulb but which one, etc, etc.
Will post in another thread.


As reported earlier, in parallel, working on lots of electronics components from one NSX.

Although being told I can take time, some of the components are required for running the engine or driving.
Aiming to finish all of them soon.





FCU (Fan Control Unit)

Normally, I would just re-solder it if I can confirm that it was at least operating fine before the removal.

However, I don't know enough of the background of this FCU.

Also, there are few different failure modes that can damage part of the components on this circuit board.

Thus, going to use my NSX for testing purpose later.





As seen on many original FCU, lots of hairline crack at many joints.

This photo is just showing one part of the board but there are more at different area.

In this photo, at least 6 cracks can be seen.

Regardless of craking or not, just re-solder every single joints.

Quite a lot so takes time.






Quick dash of coating.





Time for testing.

I have the mockup resistor for rad fan operation check but in order to test the a/c condenser fan, using the actual car.

After driving my NSX with my own FCU for a while, the rad fan kicked in so parked the car and swapped the FCU without running the engine.

IGSW P2 On and the rad fan operated fine so at least I have confidence in driving my NSX with this FCU.

A/C checked fine as the FCU responded properly with the CCU request of A/C On and Off.

Parked overnight to cool everything down and confirmed that the rad fan and the R&L condenser fans stayed Off when they should.





Kept driving with the owner's FCU for 32 miles over the next few days.

No abnormal rad fan operation and the A/C worked fine in cold early morning to mild afternoon weather.

Quick mockup resistor testing for rad fan Hi mode and a/c condenser fan + compressor Off situation.

Though, hope the engine would never experience such extreme heat.

Happy with the result and done.


By the way, quite impressed how well some of the trims inside the cabin is acting as sound deadening.

Removing just the upper trim behind the seat makes huge difference over the noise/sound getting inside the cabin from the point you start the engine to while driving.

No wonder why I can't hear the passenger above 2,000rpm when in Type-R with the single partition glass.

[Kaz-kzukNA1]

Being told that this NSX has aftermarket system at the R & L door speakers but the passenger footwell one was still OEM.

Don't know whether it was in use with the aftermarket system or not but sad to see the state of the unit.


Someone partially opened the speaker box and pulled the cable out for some reason and then decided to close the lid....

At first glance, all wires looked to be cut through.

Full of dust around the cone.

Will check in detail later.






The Bose AMP was of the very early spec without any coating and the green capacitors in use.

After quick measurement, powered up on the bench and just lots of squeaking noise.

Lots and lots of capacitor leakage.






Lots of cleaning and scraping the contaminated area.







After lots of effort, happy with the initial bench testing so applied conformal coating and the thermal compound.

More than 24Hr bench testing with thermal shock in between.

Used OEM head unit as the signal source with all sorts of EMI on purposely induced.

[Kaz-kzukNA1]

Time to look into the damaged internal cable.

Peeled off part of the sleeve/insulator of the wire and fortunately, the only major damage was at the black GND cable.

The rest of the wires only got the markings on the sleeve so mild heat would treat them.





Repaired the GND wire using mini-seal and the heat shrink tube.

Never use soldering where the wires can’t be fixed securely under vibration.

Don’t know why Thatcham requests the security device wires to be soldered to the OEM cables….





Wrapped in new EPT sealer.












Another 24Hr testing with additional Bose speaker cone in place of centre speaker.

All testing passed and done.



Moving onto the 2 x CCU boards.

One should be easy, the other one showing lots of leakage but hope I can fix it.


Now that the A/C CCU board is discontinued from Honda, this spare one would become precious.


Kaz

[Kaz-kzukNA1]

Already in the test driving mode for the 2 x CCU boards so just quick update.






The 1st board was the latest spec and according to the owner, it was replaced by Honda dealer in the past.

Although the owner reported that the fan speed only operated at max speed setting, most likely the cause was outside of the CCU such as relay, etc as no issues were found.

As seen on the same spec circuit board, it takes more time removing the extra thick coating than replacing the capacitors.

Even using the suitable nozzle diameter, the thick coating can cause partial blockage of my trusted vacuum pump operated de-soldering gun.

Had to use hand operated manual de-solder at many locations.







Still, just minimum extra time required, conformal coating applied, quick bench test and ready for the input/output testing using my NSX.


Following photos were all taken after finishing the service on the 2nd board so the timeline is out of sequence.

However, to keep this post related to the 1st board, going to post them here.





Input/output check using the Self Diagnosis test.




Followed by the Function & Operation check.



Mode control, fan speed control, A/C On/Off, Fresh/Re-circ, etc all worked fine.




Water valve control checked.



Normally, I won’t put mileage on the latest-latest board but since the display module was hand carried together, going to put small amount of mileage with this display module.

This will result in no disassembly required on re-installation and thus, if still the fan speed control doesn’t work properly, it's something outside of the CCU.


Moving onto the 2nd board that was given to the owner as a spare by someone.

[Kaz-kzukNA1]

This is the spare board that the owner was given by someone in the past.


Someone already tried replacing 2 of the capacitors on this board but .....

It damaged the through holes and the pads.





No much cleaning carried out so the acid was still chewing into the circuit board.







Lots of contamination found and at least, 3 resistors had to be removed for cleaning and repair purpose.






Lots of cleaning, scraping, etc.







At the end, 2 hard wires, 4 jumpers, lots and lots of soldering bridge used for repairing the dissolved tracks and pads.






Conformal coating applied and the same tests carried out as per #1 board.






Started putting some mileage on this spare board first.

Display module illumination checked.

Aiming to cover 50km/30+miles and already covered 20miles so bit more to go.

Then, swap the board with the #1 one.



Moving onto the Gauge Cluster and the Audio Head Unit.



Kaz

[Kaz-kzukNA1]

Already halfway through the Gauge Cluster service.

Having fun with the NSX at my place.
Well, not really….
All these extra wires behind the glove box and need access for removing the classic ABS controller during the ABS upgrade.
Just don't want ending up not being able to start the engine again.


So, quickly summarise and close the service on these two A/C CCU boards.

First, test driving with the #2 spare board.


Covered 34miles/55km of test driving session.
Went through scenario testing under all sorts of temperature, vibration, EMI environment.
If something doesn't work, most likely, it's caused by something outside of the CCU board.







Now the #1 main board.
Normally, I won’t put any mileage on the latest-latest spec circuit board as my test procedure using my NSX is enough.
However, since I had the display module here and had to take the #2 spare board out of the cabin, just placed small amount of mileage.

There is no need separating the display module on re-installation.
Again, if something doesn’t work, the cause is most likely outside of the CCU.

Both board worked flawlessly and no problem at all.

Happy with the result and ready to be returned to the owner.



Already in the process of preparing for the gauge cluster calibration.
Lots of capacitor leakage so took fair amount of extra time.

Kaz