Gauge Cluster Capacitor Replacement

[Heineken]

Failing capacitors at the gauge cluster of the NSX is a serious topic. First signs are a non-accurate speed indication or a permanently lit brake light warning even though bulbs and wiring are OK. The leaking acid near the warning indicator circuit can cause a short and even potentially lead to a fire. Same as with the other capacitor issues a replacement should be considered before the unit fails.

From a soldering point of view, replacing the capacitors on the gauge cluster isn't too complicated. The PCB is rather standard and there are no large copper areas that would require strong tools to get up to temperature. There are other things to consider, though. We'll come across these while talking about the steps for the replacement on my 1997 JDM AT gauge cluster.

If the cluster hasn't been re-calibrated yet than the readings should still be accurate after the exchange. In these cases it should be sufficient to check the speedometer after re-installation into the car using a mobile phone. Once the state of calibration is unknown, test equipment (a signal generator or gauge tester) is needed to re-calibrate the speed and potentially RPM gauges.

After removal of the cluster from the vehicle (there's a nice write-up here) the unit can be examined in detail. The first item to remove is the opaque white plastic cover at the back. To do so, unscrew the large black bulb holder by turning it about a quarter of a revolution and pulling it from the PCB followed by removing the cable from its support points.



To detach the cover, unscrew all the yellow screws. The zinc- and silver coloured ones don't need to be touched yet. Now unhinge the cover from the white tabs on the borders of the casing and put the cover aside.
By the way, the blue tape on the top covers the variable resistors for calibration of the RPM and speed gauge which will be covered at a later point.



Next have a look at the PCB with the silver-coloured screws holding it in place and here comes the first warning:

Those silver coloured screws electrically connect the PCB to the gauges on the housing (fuel, voltage, temperature, oil pressure, speed and RPM).
Removal is of no risk but re-installation is a delicate job which we will cover when we reach the corresponding part.

All bulbs can remain in the PCB. To separate the PCB from the housing it's necessary to disconnect the cables between the two PCBs as well as the trip and odometer stepper motor connection. This can be a little tricky as they are a tight fit. A set of dentist hooks is helping but should be used with caution.

As mentioned in the entry about the gauge cluster bulb replacement it's advisable to replace all the illumination bulbs as well as the 'D' indicator on AT vehicles after about 100.000 km. They are typically darkened considerably at this mileage and the risk of failure is increasing.

Now the most time consuming part starts. The selection of replacement capacitors. Due to the nature of the failure I decided to focus on the wet electrolyte ones on the board and trying to replace them with dry (Aluminium Polymer) ones. As these are analogue circuits and two special capacitor types are to be considered (low leakage and bi-polar) it's not possible in all cases.
Additionally, the correct capacitance, sufficient voltage rating and size of the replacement has to be considered. When offered with several alternatives, the one with the longest life time was chosen:

Left PCB (component view)
[TABLE="class: grid, width: 1024"]
<tbody>[TR]
[TD]Name[/TD]
[TD]Original
[/TD]
[TD]Replacement[/TD]
[/TR]
[TR]
[TD]C1[/TD]
[TD]2200 μF 16 V 105 °C ↨ 20 mm ∅ 12 mm RM5
Nippon Chemicon KMG (wet electrolyte)[/TD]
[TD]2200 μF 16 V 105 °C 20,000 h ↨ 21.5 mm ∅ 10 mm RM5
United Chemicon PSG (dry electrolyte)[/TD]
[/TR]
[TR]
[TD]C3[/TD]
[TD]3.3 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]3.3 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C5[/TD]
[TD]2.2 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]2.2 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C12[/TD]
[TD]10 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]10 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C17[/TD]
[TD]33 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]33 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 6.3 mm RM2.5
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C18[/TD]
[TD]47 μF 16 V 105 °C ↨ 10 mm ∅ 5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]47 μF 25 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C19[/TD]
[TD]33 μF 10 V 85 °C ↨ 10 mm ∅ 5 mm RM2
Nippon Chemicon LLA (wet electrolyte)
⚠ Low Leakage[/TD]
[TD]33 μF 25 V 105 °C 1000 h ↨ 12 mm ∅ 5 mm RM2
Nichicon UKL - Low Leakage[/TD]
[/TR]
[TR]
[TD]C20[/TD]
[TD]10 μF 16 V 85 °C ↨ 10 mm ∅ 5 mm RM2
Nippon Chemicon LLA (wet electrolyte)
⚠ Low Leakage[/TD]
[TD]10 μF 25 V 105 °C 1000 h ↨ 12 mm ∅ 5 mm RM2
Nippon Chemicon LLA - Low Leakage[/TD]
[/TR]
[TR]
[TD]C21[/TD]
[TD]100 μF 16 V 105 °C ↨ 10 mm ∅ 7 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]100 μF 16 V 105 °C 10,000 h ↨ 12.5 mm ∅ 6.3 mm RM2
United Chemicon LE (wet electrolyte)[/TD]
[/TR]
</tbody>[/TABLE]

Right PCB (component view)
[TABLE="class: grid, width: 1024"]
<tbody>[TR]
[TD]Name[/TD]
[TD]Original[/TD]
[TD]Replacement[/TD]
[/TR]
[TR]
[TD]C1[/TD]
[TD]see Left PCB - C1[/TD]
[TD]see Left PCB - C1[/TD]
[/TR]
[TR]
[TD]C3[/TD]
[TD]see Left PCB - C3[/TD]
[TD]see Left PCB - C3[/TD]
[/TR]
[TR]
[TD]C5[/TD]
[TD]6.8 μF 25 V 105 °C ↨ 5 mm ∅ 3.5 mm RM2
-unknown manufacturer- (wet electrolyte)[/TD]
[TD]6.8 μF 25 V 105 °C 3000 h ↨ 6 mm ∅ 6.3 mm RM2.5
Panasonic SEP (dry electrolyte)[/TD]
[/TR]
[TR]
[TD]C14[/TD]
[TD]see Left PCB - C12[/TD]
[TD]see Left PCB - C12[/TD]
[/TR]
[TR]
[TD]C15[/TD]
[TD]47 μF 25 V 105 °C ↨ 7 mm ∅ 7 mm RM2
Nippon Chemicon KMA (wet electrolyte)[/TD]
[TD]47 μF 35 V 125 °C 1000 h ↨ 6 mm ∅ 6.3 mm RM2.5
Panasonic SEK (dry electrolyte)[/TD]
[/TR]
[TR]
[TD]C17[/TD]
[TD]47 μF 25 V 105 °C ↨ 10 mm ∅ 7 mm RM2
Nippon Chemicon KME (wet electrolyte)
⚠ Bi-Polar[/TD]
[TD]47 μF 25 V 105 °C 1000 h ↨ 12.5 mm ∅ 6.3 mm RM2.5
Nippon Chemicon UEP (wet electrolyte)[/TD]
[/TR]
[TR]
[TD]C18[/TD]
[TD]See C18 ↑[/TD]
[TD]See C18 ↑[/TD]
[/TR]
</tbody>[/TABLE]

All the types above are available from digikey. In case your cluster's capacitors are identical feel free to use this shopping cart for an order: https://www.digikey.de/short/zbhfd5

De-soldering can be accomplished by means of de-solder wick or a manual de-solder pump. Using a vacuum unit is more comfortable, of course but not strictly necessary.
Soldering the new parts requires no special tools, a normally sized (~30 W) iron is sufficient, a temperature regulated one even better but not a must.

Now everything has to be put back together. In theory the same steps as during disassembly just in reverse order. Connecting the stepper motors is (again) a little fiddly but can be accomplished without special tools.

The most dangerous part is attaching the PCB to the housing by means of the silver-coloured screws. As mentioned before, they are responsible for the electrical connection of the gauges to the PCB.
Their threads are located inside the gauges and are easy to twist-off. Hair-thin wires are attached to them. If a twist-off happens they are very likely to snap.
This can be repaired but is a very delicate task and replacement gauges are expensive. To avoid any of this from happening it's best to follow these rules:

• Insert the and rotate the screws with your fingers until they are safely engaged.
• Use a screwdriver and rotate the screw with two fingertips (not more) until the spring washer just starts to compress.
• Tighten the screw further until the washer just reaches full compression, a few degrees more at a maximum.

After all this has been accomplished successfully the unit can be installed back into the car.

Check if all lamps light up, backlight is working, RPM and speed values are correct. If no adjustments have been made to the calibration potentiometers the display should still be sufficiently accurate. In any case, ensure that the displayed speed is not below the actual speed as this is illegal in most countries.

<< -- continued below -->>

 

[Heineken]

As I spent much time to create a gauge cluster calibrator I would like to explain the calibration procedure here.

The tester can drive the two main gauges (RPM and speed) with proper signals as well as provide reference resistance for the temperature, oil, fuel and voltage gauge. Even though the signals are mostly the same, pin numbers changed in 1995 creating two pin-outs: 1990-1994 and 1995-2005. Compatibility with all build years is given, except the temperature gauge in USDM (Acura) vehicles starting build year 2000.

To be able to move the needles, we need to supply voltage and ground for each side of the PCB. The left socket drives the RPM, temperature and oil gauge, the right one speed, fuel and voltage.

Left socket (A) - RPM
[TABLE="class: grid, width: 1024"]
<tbody>[TR]
[TD]Name[/TD]
[TD]PIN (1990-1994)
[/TD]
[TD]Pin (1995-2005)[/TD]
[/TR]
[TR]
[TD]12 V[/TD]
[TD]A3[/TD]
[TD]A13[/TD]
[/TR]
[TR]
[TD]Ground[/TD]
[TD]A2[/TD]
[TD]A27[/TD]
[/TR]
[TR]
[TD]RPM[/TD]
[TD]A4[/TD]
[TD]A28[/TD]
[/TR]
[TR]
[TD]Temperature[/TD]
[TD]A17[/TD]
[TD]A12[/TD]
[/TR]
[TR]
[TD]Oil Pressure[/TD]
[TD]A1[/TD]
[TD]A14[/TD]
[/TR]
</tbody>[/TABLE]

Right Socket (B) - Speed
[TABLE="class: grid, width: 1024"]
<tbody>[TR]
[TD]Name[/TD]
[TD]Pin (1990-1994)[/TD]
[TD]Pin (1995-2005)[/TD]
[/TR]
[TR]
[TD]12 V[/TD]
[TD]B9[/TD]
[TD]B2[/TD]
[/TR]
[TR]
[TD]Ground[/TD]
[TD]B8[/TD]
[TD]B7[/TD]
[/TR]
[TR]
[TD]Speed[/TD]
[TD]B24[/TD]
[TD]B22[/TD]
[/TR]
[TR]
[TD]Fuel[/TD]
[TD]B10[/TD]
[TD]B1[/TD]
[/TR]
</tbody>[/TABLE]

Pin numbers can be identified by looking into the socket counting from left to right, top to bottom. The top row is 14-1, the bottom row 30-15.
Note that the brake light warning and SRS warning lamp light up when power is correctly supplied to both PCBs sockets (due to missing input signals).

Calibration starts by selecting the highest RPM (8000) first at the tester and working with the left two variable resistors. The right one of the two is controlling the upper range and is now used to put the needle to exactly 8000 RPM. Next we jump to 1000 RPM to calibrate the lower end. Now the intermediate values are checked and if the 8000 RPM is still correct. If not, recalibrate the value 8000 then check 1000 again (and adjust if necessary).
On every cycle the deviations should become smaller until all values are correct. It shouldn't take more than a few rounds.

The speed gauge is calibrated in the same fashion, utilizing the other two variable resistors. Be reminded again that it may never show a too low value as this is against the law in most countries.

The text became much longer than expected but hopefully helpful to those interested

 

[MotorMouth93]

The first symptom that I had capacitor issues was my speedometer reading off. I was trying to figure out why there was so much wind noise and why everyone was driving so slow on the highway -- turned out that I was going 85 and not 65 like the speedo said!

When I opened the cluster up to do the repair none of my capacitors were leaking but replacing them fixed it 100% as far as I can tell.

Thanks for sharing all of this info, I might have to build a little calibration tool using one of the various development boards I have laying around.

 

[sca037]

GREAT write-up, thanks!

 

[Heineken]

Thanks :smile:

PS: Had to hotlink the images from nsxcb.co.uk until the image upload issues is resolved - hopefully they are visible now.

 

[Big McLargeHuge]

This is the thread to link to whenever the weekly question comes up on FB about gauge cluster repairs :biggrin:. This really explains everything.

Most annoying part for me was de-soldering the black IC next to the 3 worst capacitors, with a small-tip soldering iron and wick it took forever.

Are the factory wiring diagrams you posted from a JDM or US/EU based manual? I ask because I believe the pinouts & connector numbers for JDM cars are largely different than other markets, but were the wiring colors in your car the same as a US spec car? (i.e., both your JDM car and a US/EU/whatever LHD car have a BLU/WHT wire for the oil pressure sender, even if the pins & connector names are different?)

 

[Heineken]

The wire diagrams are from the Acura "Electrical Trouble Shooting Manual 97-02" that I bought a few months ago.

Pin numbering and wire colours have been extensively checked together with Drew (thanks again!) and there was no wire colour or pin number difference between USDM and JDM.
The actual pinning did however change considerably (worldwide) in 1995 but the wire colours stayed the same (except some minor differences).

Different gauges have slightly different functionality (e.g extra or missing warning lights) but this was realized by separate pins, as far as we could elaborate.
Note that only the USDM (Acura) temperature input pin is driven differently starting build year 2000. That's the only functional difference on a single pin we could identify.

 

[crxguy52]

Excellent write-up! This is the next project I need to tackle after the radio and SRS unit (which I wasn't able to fix, unfortunately). Thanks for making a great contribution to the community!

 

[Odortiz]

gauge cluster replacement caps, 92 manual

one humid morning, i started the car, and all the indicators at low center on the cluster stayed lit for about a minute. i took that as a sign it's time to replace the capacitors.
based on a previous writeup of doing this job, i ordered his list of caps, only to find out my 92 cluster has a different set of caps.
i have no idea if my cluster is original to the car, but here is my list of caps i ordered , including Mouser part numbers.a couple caps were unavailable, so i had to chose ones with the next higher voltage rating.
if you'll be DIYing this, i strongly recommend you open up your cluster before ordering, to confirm your capacitors. it's not a difficult job if you have experience soldering and desoldering from circuit boards.
here is the thread i found very helpful when doing the job, and used his list to order parts.
http://www.nsxprime.com/forum/showthread.php/214284-Gauge-Cluster-Capacitor-Replacement
his list was not correct for me. my list is posted below.

	Original	Replacement
Left (tach side)
C1	2200μF 16V	2200μF 16V	EEU-FR1C222
C3	3.3μF 50V	3.3μF 50V	ULD1H3R3MDD1TD
C5	2.2μF 50V	2.2μF 50V	ULD1H2R2MDD1TD
C12	33μF 50V	33μF 50V	ULD1H330MED1TD
C13	47μF 16V	47μF 16V	ULD1C470MDD1TD
C14	33μF 10V LOW LEAKAGE	33μF 16V LOW LEAKAGE	UKL1C330KDDANA
C15	10μF 16V LOW LEAKAGE	10μF 16V LOW LEAKAGE	UKL1C100KDDANA
C16	100μF 16V	100μF 16V	ULD1C101MED1TD
Right (speedo side)
C1	2200μF 16V	2200μF 16V	see C1 above
C3	3.3μF 50V	3.3μF 50V	see C3 above
C5	6.8μF 25V	6.8μF 25V	UMF1E6R8MDD1TP
C14	10μF 35V	10μF 50V	UPV1H100MFD1TD
C15	47μF 25V	47μF 25V	EKMA250ETD470MF07D
C17	47μF 25V BIPOLAR	47μF 25V BIPOLAR	UEP1E470MED
C18	47μF 25V BIPOLAR	47μF 25V BIPOLAR	see c17 above

<tbody>
[TD="width: 185"]Mouser PN[/TD]

</tbody>

 

[Heineken]

Correct, the parts list is for a 1997 JDM AT cluster - as stated in the post. Unfortunately I did not recap any other cluster yet so no other parts list was available to me.

 

[drew]

Hey @Odotiz, great work, but you should just add this to the thread you indicated.

It puts a knowledge base in one place so we can find everything...it can be very hard to find your detailed information at a later date

 

[Honcho]

**MODERATOR NOTE***

Moved here to keep the topic organized.

 

[Wild Turkey]

So how do we know whether to do this or not?

What a fascinating and well documented thread! My 1995 dash works fine. I have no way to check the tach, but the speedo is bang on the GPS speed. The only questionable gauge is my fuel tank, which reads 1/4 when it's actually 3/8 or maybe 5/16. I had put it down to the fact that fuel gages weren't that accurate back in '95. I've never had the fuel light go on because I keep it above 1/4 to help cool the fuel pump? (I don't know if that's even true.)
Options:

• Winter project to replace capacitors on perfectly functioning gage cluster? Possibly break one of those tiny wires or screw something up soldering. Negatives:
  • a couple of days work
  • waiting for parts if I find something else broken
  • Possibly have to buy new gauge cluster if I break something
• Leave it & possibly have a 25 year-old capacitor leak and ruin something - will this definitely happen eventually like the speakers and the climate control? Negatives:
  • worry about this when I'm on a trip. Fire?!?
  • Possibly have to buy new gauge cluster.

Seems like both options have big potential up-side and down-side. What to do?
Also, constructing this calibrator circuit box seems above my skill set. How many potentiometers need to be adjusted and how hard was it to do with the GPS and a volt meter? You have to put the cluster back in and drive around to check things/pull it out and adjust/repeat? Can you read the RPM's off the OBD2? Is the low fuel light its own sensor or does it respond to a certain voltage on the fuel level sender and have to be calibrated too?
Or perhaps most importantly, who can I send this to have it done and recalibrated?

 

[Heineken]

Let's tackle this step by step, shall we ..

Regarding the question whether to replace them now would be a clear "yes" from me. Simply because the risk of breaking something in the process stays the same but when the capacitors start leaking a lot more than just capacitor replacement is required - so do it when it's still easy as opposed to waiting until it becomes difficult. Note that leakage in the cluster can lead up to a cabin fire if ignored for (way) too long.

Based on experience so far, there's no need to re-calibrate (using the two potentiometers each for RPM and speed) if they haven't been touched before. Several members reported they just replaced the caps and the speed was still dead-on.

The fuel meter isn't calibratable by the way (only speed and RPM). If it displays strange values I would search somewhere else first.

Summary from my point of view: Do it this winter, do not calibrate, should be OK :smile:

 

[acuhon]

one humid morning, i started the car, and all the indicators at low center on the cluster stayed lit for about a minute. i took that as a sign it's time to replace the capacitors.
based on a previous writeup of doing this job, i ordered his list of caps, only to find out my 92 cluster has a different set of caps.
i have no idea if my cluster is original to the car, but here is my list of caps i ordered , including Mouser part numbers.a couple caps were unavailable, so i had to chose ones with the next higher voltage rating.
if you'll be DIYing this, i strongly recommend you open up your cluster before ordering, to confirm your capacitors. it's not a difficult job if you have experience soldering and desoldering from circuit boards.
here is the thread i found very helpful when doing the job, and used his list to order parts.
http://www.nsxprime.com/forum/showthread.php/214284-Gauge-Cluster-Capacitor-Replacement
his list was not correct for me. my list is posted below.

	Original	Replacement	Mouser PN
Left (tach side)
C1	2200μF 16V	2200μF 16V	EEU-FR1C222
C3	3.3μF 50V	3.3μF 50V	ULD1H3R3MDD1TD
C5	2.2μF 50V	2.2μF 50V	ULD1H2R2MDD1TD
C12	33μF 50V	33μF 50V	ULD1H330MED1TD
C13	47μF 16V	47μF 16V	ULD1C470MDD1TD
C14	33μF 10V LOW LEAKAGE	33μF 16V LOW LEAKAGE	UKL1C330KDDANA
C15	10μF 16V LOW LEAKAGE	10μF 16V LOW LEAKAGE	UKL1C100KDDANA
C16	100μF 16V	100μF 16V	ULD1C101MED1TD
Right (speedo side)
C1	2200μF 16V	2200μF 16V	see C1 above
C3	3.3μF 50V	3.3μF 50V	see C3 above
C5	6.8μF 25V	6.8μF 25V	UMF1E6R8MDD1TP
C14	10μF 35V	10μF 50V	UPV1H100MFD1TD
C15	47μF 25V	47μF 25V	EKMA250ETD470MF07D
C17	47μF 25V BIPOLAR	47μF 25V BIPOLAR	UEP1E470MED
C18	47μF 25V BIPOLAR	47μF 25V BIPOLAR	see c17 above

<tbody>
</tbody>

the

Great first post. Thanks for making the list . Those bipolar capacitors are out of stock. What is best quality capacitors we can get ? I don't think that I'll be able to do it in 30 years again.

 

[Old Guy]

Options:

• Winter project to replace capacitors on perfectly functioning gage cluster? Possibly break one of those tiny wires or screw something up soldering. Negatives:
  • a couple of days work
  • waiting for parts if I find something else broken
  • Possibly have to buy new gauge cluster if I break something
• Leave it & possibly have a 25 year-old capacitor leak and ruin something - will this definitely happen eventually like the speakers and the climate control? Negatives:
  • worry about this when I'm on a trip. Fire?!?
  • Possibly have to buy new gauge cluster.

Seems like both options have big potential up-side and down-side. What to do?

Give some consideration to where your car has spent its life.

The lifetime of electrolytic capacitors is temperature dependent, loosely described by something called Arrhenius reaction rate theory. For aluminum electrolytic capacitors which are the 'problem capacitors' in the NSX (not just the NSX), one of the life performance factors is something called Effective Series Resistance (ESR). When a capacitor vendor tells you that they have a 2000 hours rating they are specifying that the capacitor will meet certain performance requirements for that period of time, not that the capacitor will last 2000 hours. One of the factors that ages out is ESR which increases with age and temperature. ESR is important because as it increases with age it causes the capacitors to heat up more during operation leading to deterioration of the electrolyte in the capacitor which leads to more heating of the capacitor which leads to eventual rupture. The failure that seems to get the most attention in engineering reports is when there is a run away condition that leads to the rupture disc on the top of the capacitor blowing and the capacitor ejecting its guts all over the place. The slow ejection of the seal due to long term high internal pressures and gradual leakage of electrolyte seems to be of less interest (electrical engineers are attracted to things that go boom?).

Why does the preceding matter? I did the capacitor changeout thing in my CCU at 20 years. The capacitors were an interesting mix, most being Nichicon 2000 hr capacitors, some rated at 85C and some at 105C. None of the capacitors showed any signs of seal leakage. The Arrhenius reaction rate theory says that the performance lifetime of the capacitors roughly doubles for every 10C drop in temperature. So, the 85C 2000 hr capacitors will have a roughly 32,000 hour performance lifetime at 45C. Where I live the hourly annual mean ambient is about 2 C. Hypothetically a 85C 2000 hr capacitor would have a performance lifetime of 512,000 hrs or 58 years at that temperature. That is a stretch because mean temperature is not a valid temperature for calculating life in a highly non linear formula like the Arrhenius formula. Also, the lifetime doubling for every 10C drop rule kind of falls off the edge of the world when you stray more than 40C from the rated temperature. But, its just a way of saying that my car which has spent 80% of its life in Manitoba and Saskatchewan and is a garage queen and is only exposed to internal cabin temperatures over 40 C perhaps 15 hours per year when parked outside. Based upon my CCU experience and my examination of the door amplifiers I don't expect capacitor failure any time soon (failing solder joints is a different and separate problem).

If your car is a US vehicle and lived all its life parked outdoors in Phoenix, I would probably be giving serious consideration to dealing with a potential capacitor problem (all of them, not just the cluster). If it was a Canadian vehicle which was a garage queen and spends 40% of the year wrapped up for winter storage I might be inclined to direct money to other maintenance issues. As a related observation, I am only aware of one vehicle fire which reportedly was attributed to a problem originating in the cluster. The more common problem is the warning lights / brake failure indication and drifting of tach and speedo calibration giving you advance notice that something is up (like the noisy door amplifiers).

If you feel the need to research the capacitor failure problem some more, the following are moderately light reads

What Influences Electrolytic Capacitor Lifespan? | Altium

Thermal stress on capacitors: failure prevention - EE Publishers

 

[Wild Turkey]

My 1995 lived 22 years in Florida until 2017 when it moved to Canada, so I guess I'll put the capacitors on my winter list. The AC and speaker caps were done around 2010. I'll be sure to document the caps on a 1995 manual transmission. I've got a temp-controlled iron; time to buy a good desoldering tool and learn about removing/replacing coatings on the circuit boards. I'll definitely replace the illumination bulbs.


Crazy question: How much work would it be to change the variable resistors for the speedo to read in km/hr?

 

[drew]

If you're not happy with the primary speedo clocking in MPH, you can get new gauge faces
https://lockwoodinternational.co.uk/?s=nsx&post_type=product

The very hard part is the removal of the gauge needle without destroying the stepper motor. Needle pliers are a must!

The calibration is not super difficult but will require Heineken's tool or my instructions using a signal generator.

 

[drew]

regarding alternatives, if you cannot find the exact one you are looking for:

you can use a cap with a higher voltage rating with the same capacitance. Just make sure it physically fits, you can bend the cap over there is room.

I like to use tantalum as well as poly caps.

If you are going spend a few hours of your time and deal with an expensive fragile part: get the stuff that is going to outlast the vehicle.

 

[Heineken]

If you're ordering from a reputable distributor like Digikey or Mouser, all brands offered should be OK (like Nichicon, TDK, Chemicon, Panasonic, etc.).
To improve lifetime, you can choose types which are rated as such (105 °C at 2000 h or more).

In case a specific value isn't available, try uprating the voltage but ensure the resulting size is still suitable for the place where they are going to be installed.

If you're primarily afraid of leakage happening again, choose Alumunium Polymer capacitors since these don't contain any liquid. Note that they are a very good choice for all voltage stabilization tasks (typically the big and leaky caps in our cars) but not ideal for audio paths, decoupling or where low electrical leakage is required (like in several places on the cluster). Voltage stabilization caps can be identified by having fairly large values but if in doubt stick to high quality electrolytic caps.

Great first post. Thanks for making the list . Those bipolar capacitors are out of stock. What is best quality capacitors we can get ? I don't think that I'll be able to do it in 30 years again.

 

[Old Guy]

. I've got a temp-controlled iron; time to buy a good desoldering tool and learn about removing/replacing coatings on the circuit boards.

An electric vacuum de soldering tool can be a useful. However, unless you have a lot of capacitors to remove solder wick can be a low cost solution. Just make sure the wick is fresh and kept sealed up. The wick has flux embedded in it and if left exposed to the air for long periods of time the flux degrades reducing the effectiveness of the wick.

Acrylic conformal coating can be removed by using isopropyl alcohol and a toothbrush. It will probably take a couple of applications. I use 99% IPA because it is what I have on hand; but, 70% will probably do the trick. The conformal coatings on the NSX circuit boards that I have fiddled with have all yielded to IPA. However, different boards come from different vendors and some may have non acrylic coatings that require special strippers.

Be sure to remove the conformal coating before removing the capacitors. If you try to de solder through the conformal coating, the coating melts and fouls the tip of the iron or the de soldering tool which reduces heat transfer with the result that the job goes badly. After the solder repairs, clean off the board with flux remover and a tooth brush and then apply new conformal coating. Mask any electrical contacts (interconnecting plugs) or exposed switch contacts to prevent conformal coating from getting on them because it is an electrical insulator. The local electronics supplier where I get my chemicals sells MG Chemicals which is what I use for solder, flux remover and conformal coating. There are other suppliers that probably work just as well.