NSX climate control board failures

[BryanZublin]

This posting is part information and part advertisement.

The informational part:
I have posted two pictures that show an NSX climate control board prior to being repaired. The original electrolytic capacitors start to leak over time (years) and corrode the circuit board pads, traces and component leads. The amount of damage that can occur from the leaking capacitors can be severe. I repaired one board that had 3 leaking caps which resulted in 15 corroded or broken connections and 4 corroded parts that had to be replaced (separate from replacing all 13 electrolytic capacitors).

There have many reports of failed boards and the problem seems to be widespread. If anyone ever has their dashboard apart, I strongly suggest that they have the board checked out and the capacitors replaced and any required repair performed. This saves the hassel of having to remove the board when it actually fails, and eliminates the risk that the board will be unrepairable because of too much damage and no spare parts. The cost of repair is one quarter the cost of a new board.

The advertisement part:
I have started repairing the climate control boards for the NSX, through Dali Racing. This consists of removing all of the electrolytic capacitors, removing the corrosion, cleaning, visual inspection of PCB pads and traces, installing new electrolytic caps, replacing any other corroded parts, repairing broken traces with wire jumpers, cleaning, and visual inspection.

Bryan Zublin
Zublin Engineering

 

[drew]

Will you use tantalums if requested?

Price?

 

[Briank]

The capacitor leakage does make a mess of the board some worse then others.

I have never priced non-electrolitc capacitors, but they are much more expensive.

Bryan how are you testing the boards to confirm they are in working order when you are done with them?

 

[BryanZublin]

BrianK,
The tests I perform consist of the following:
Continuity to verify all repaired traces.
Measure 5V regulator voltage.
Verify front panel display and all buttons select the proper item.
Verify fan HI request relay operation.
Verify display bright/dim function.

In the future I would like to connect the full wire harness & other items to the board so that I can verify the operation of the vent motors, fan speed, sensors, etc. There is an NSX parts car sitting in my garage, I just need to remove the relevant items.

Drew,
I have not priced out all of tantalum caps. The high capacitance / higher voltage tantalum caps get expensive and are not very common. For example, a 330 uF 10V leaded tantalum cap is more than $5 each in small quantities. There are design issues with tantalum caps related to inrush current and equivalent series resistance (lower is not always a good thing) so it is not advisable to blindly replace the original electrolytics with tantalum.

For my repair, I use 50V caps for all 13 parts even though some are originally rated 10V. This should help with the long term reliability.

Bryan Zublin

 

[Briank]

Testing is the most important part of the repair like they say returns are a bitch.

My complete test fixture, a bitch to build but worth it's weight in CCU's Bryan let me know when you find the mistakes is the ETM. :wink:

 

[Semnos_NSX]

BrianK –
I guess you don’t mess around!! That is one heck of a testing station!! Nice work!!

 

[BryanZublin]

BrianK,
Very nice test setup. Another option would be to add a switched harness to my '92 NSX so that I could plug in the CC board and test it on the NSX with the engine running. It would "only" require about 30 relay contacts. :-0

Regarding the Electrical Troubleshooting Manual (ETM), I have the books for years 92-02 and the CD rom for the later years, so I think I found all of the errors in the early ETM. See below, let me know if I am close. ;-)

Connector C419
Pin 10 shown as Reference Voltage Output, should be Vent motor control input/output (Vent close).

Connector C418
Pin 3 shown as Sunlight Sensor Input, should be Mix door position sensor input (Mixer-P).

Bryan

 

[DocL]

BrianK –
I guess you don’t mess around!! That is one heck of a testing station!! Nice work!!

Yep, and that's why he doesn't have A/C or heat in his NSX! :biggrin:

 

[Briank]

Yep, and that's why he doesn't have A/C or heat in his NSX! :biggrin:

No, my car is my backup test fixture, or I should say first test fixture. Works great in the off season but a pain in the driving season.

 

[Briank]

BrianK,
Very nice test setup. Another option would be to add a switched harness to my '92 NSX so that I could plug in the CC board and test it on the NSX with the engine running. It would "only" require about 30 relay contacts. :-0

Regarding the Electrical Troubleshooting Manual (ETM), I have the books for years 92-02 and the CD rom for the later years, so I think I found all of the errors in the early ETM. See below, let me know if I am close. ;-)

Connector C419
Pin 10 shown as Reference Voltage Output, should be Vent motor control input/output (Vent close).

Connector C418
Pin 3 shown as Sunlight Sensor Input, should be Mix door position sensor input (Mixer-P).

Bryan

Nice job got both of them. :biggrin: