Today at Atelier Kaz - ex-Honda R&D, F1, Indy/CART engineer

Hi Kaz,

Is this purely age-related - in other words will a 1991 be in a worse state than a 2005?
Or is it that all NSX of all ages will need capacitor replacement etc. now?

I am coming to the UK in June next year - should I bring all my modules with me to give to you to check and repair as required?

Thanks,

Nick

There is no definite answer to this as the main factor is the heat condition that could be affected by which country you live, which part of the country you live, how the car is driven, usage of A/C, usage of aftermarket ICE mounted just below the CCU that could cook it if built-in AMP used, etc, etc, etc.

Addition to this, the angle of the way the CCU is mounted doesn’t help.
It is mounted with some angle and not flat that the longer you leave, the acid can run down the wide area of the circuit board and it depends on the vibration level.
Even if it started leaking, if the car was kept in storage, the acid tends to stay in one place than spreading all over the place.
Having said this, on some of the board, the acid penetrated into the board deeply that the acid could end up at the back side of the board as well causing more trouble.

All caps on A/C CCU board were rated at 105degC (not the case for some of the caps inside the audio head unit) but probably only 1,000hrs at that temperature.
Obviously, cabin temperature would be lower than that so would survive much longer time but it can reach well over 60degC when parked under direct sun light.

Also, when you are driving the car, the CCU board will be powered up regardless of whether you are using the a/c or not so that will shorten the life as well.
And the position of the CCU board doesn’t help.
OEM head unit is right at the base of the CCU and it can get fairly warm when in use.
OEM system produces pre-AMP signal so won’t get as hot as some of the aftermarket unit with built-in AMP but still it can cook the CCU.

Imagine how hot it can get if you have aftermarket ICE under the CCU with display, DVD, etc or even the built-in AMP there.


So, many factors will affect the state of one’s CCU and Head unit circuit board so you will see all sorts of different level of damages but for sure, if it’s early/mid 90’s models, one should act now but probably too late and enough damages were already done.
You just don’t notice it until you actually start experiencing the issue.


The manufacture did change the spec of the caps a few times.

One of the easiest way to tell the old/mid/new spec difference is the colour of the cap body.

If all of them are in black, you must act now.
If they are mixture of black and brown, again, you must act now.
If all of them are in brown, you have better chance of surviving longer but not free from leakage.


I saw from around 98 models, the manufacture started using the mixture of black and brown caps and later switched to all brown.
The CCU from 98 model with mixture of black/brown cap were already showing severe damages several years ago….


When I serviced CCU from 2005 model in 2014, there was no leakage at all so it was an easy service but in the same year, when I serviced the one from 2002 model, there was already small leakage on one cap but then the one from 2000 model was fine so again, it all depends on the usage environment.


Similar story on the Main relay.
Long time ago, already the one on 2002 model failed and the owner couldn’t re-start his engine.
I just started servicing another NSX from early 90’s and the Main relay was surprisingly the original one from the factory with already lots of soldering crack.
However, the owner didn’t notice any issues so again, the environment factor plays the big role.


And on top of these, it’s up to to the owners to make the final decision.
Because of my background, I don’t like waiting until the parts to fail before making decision.
The reason why I’m against the widely known term ‘if it’s not broken, don’t fix it’.

Nothing wrong with it and probably majority of the people are following the same notion but I prefer preventative maintenance if it is known to fail than waiting it to happen.


Kaz

Thanks for the comprehensive reply, which will help a lot of owners.