Heineken's Garage

Introduction
The Gauge Cluster suffers from ageing capacitors as many ECUs in the NSX do. Leaking capacitors at the gauge cluster is a serious issue. Acid near the warning indicator circuit causes shorts and even potentially lead to a fire. Same as with the other capacitor issues, a replacement should be considered before the unit fails.

Diagnostic
First signs are a non-accurate speed indication or a permanently lit brake light warning even though bulbs and wiring are OK.

Preparation
After removal of the cluster from the vehicle it can be examined in detail. 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. Detach the cover by unscrewing all the yellow screws (don't touch the silver coloured ones yet). Unhinge the cover from the white tabs on the borders of the case.

Warning
The silver/bronze coloured screws electrically connect the PCB to the gauges (fuel, voltage, temperature, oil pressure, speed and RPM).
Removal is of no risk but re-installation is a delicate job with the risk of breaking the gauges.

All bulbs can remain in the PCB but it might be easier to remove them first - if doing so, note positions and colours. To separate the PCBs from the housing it's necessary to disconnect the cable 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 pliers is helpful but used with caution.

It's advisable to replace all illumination bulbs as well as the 'D' indicator on AT vehicles every 100.000 km. They are typically darkened considerably at this mileage and the risk of failure is increasing.

Repair
If the cluster hasn't been re-calibrated than the readings should still be accurate after the exchange. It should be sufficient to check the speed after re-installation into the car using a mobile phone. When the state is unknown, test equipment (a signal generator or gauge tester) is needed to calibrate the speed and RPM gauges.

From a pure soldering point of view, replacing the capacitors on the cluster isn't too complicated. The PCB is rather standard and there are no large copper areas requiring a powerful soldering iron to get up to temperature.

Before replacing capacitors it's necessary to check the capacitance, voltage, manufacturer series and dimensions. The cluster is mostly equipped with standard capacitors from Panasonic and Nichicon (NHE, KMG and KMA) but also features two Low Leakage (LLA) and two bi-polar (KME series) capacitors.

Left PCB (component view)

1991 (EU)	1997 (JDM AT)	Original	Replacement
C1	←	2200 μF 16 V 105 °C ↨ 20 mm ∅ 12 mm RM5 Nippon Chemicon KMG (wet)	2200 μF 16 V 105 °C 20,000 h ↨ 21.5 mm ∅ 10 mm RM5 United Chemicon PSG (dry) ‎Part Nr.: ‎APSG160ELL222MJ20S‎
C3	←	3.3 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2 Panasonic [M] NHE (GE) (wet)	3.3 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2 United Chemicon LE (wet) Part Nr.: ELE-500ELL3R3ME11D‎
C5	←	2.2 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2 Panasonic [M] NHE (GE) (wet)	2.2 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2 United Chemicon LE (wet) Part Nr.: ‎ELE-500ELL2R2ME11D‎
n/a	C12	10 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2 -unknown- (wet electrolyte)	10 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2 United Chemicon LE (wet) Part Nr.: ‎ELE-500ELL100ME11D‎ Alternative: 63 V: Part Nr.: ELE-630ELL100ME11D
C12	C17	33 μF 50 V 105 °C ↨ 10 mm ∅ 5 mm RM2 Nippon Chemicon KMG (wet)	33 μF 50 V 105 °C 10,000 h ↨ 12.5 mm ∅ 6.3 mm RM2.5 United Chemicon LE (wet)‎ Part Nr.: ELE-500ELL330MF11D‎
C13	C18	47 μF 16 V 105 °C ↨ 10 mm ∅ 5 mm RM2 Panasonic [M] NHE (GE) (wet)	47 μF 25 V 105 °C 10,000 h ↨ 12.5 mm ∅ 5 mm RM2 United Chemicon LE (wet) ‎Part Nr.: ELE-250ELL470ME11D‎
C14	C19	33 μF 10 V 85 °C ↨ 10 mm ∅ 5 mm RM2 Nippon Chemicon LLA (wet) ⚠ Low Leakage	33 μF 25 V 105 °C 1000 h ↨ 12 mm ∅ 5 mm RM2 Nichicon UKL - Low Leakage ‎Part Nr.: ‎UKL1E330MEDANA‎
C15	C20	10 μF 16 V 85 °C ↨ 10 mm ∅ 5 mm RM2 Nippon Chemicon LLA (wet) ⚠ Low Leakage	10 μF 25 V 105 °C 1000 h ↨ 12 mm ∅ 5 mm RM2 Nichicon UKL - Low Leakage ‎Part Nr.: ‎UKL1E100MDDANA‎
C16	C21	100 μF 16 V 105 °C ↨ 10 mm ∅ 7 mm RM2 Panasonic [M] NHE (GE) (wet)	100 μF 16 V 105 °C 10,000 h ↨ 12.5 mm ∅ 6.3 mm RM2 United Chemicon LE (wet) ‎Part Nr.: ELE-160ELL101MF11D

Right PCB (component view)

1991 (EU)	1997 (JDM AT)	Original	Replacement
C1	←	see Left PCB - C1	see Left PCB - C1
C3	←	see Left PCB - C3	see Left PCB - C3
C5	←	6.8 μF 25 V 105 °C ↨ 5 mm ∅ 3.5 mm RM2 Panasonic [M] -series ??- (wet)	6.8 μF 25 V 105 °C 3000 h ↨ 6 mm ∅ 6.3 mm RM2.5 Panasonic SEP (dry) ‎Part Nr.: ‎25SEP6R8M Alternative: 2000 h Nichicon Part Nr.: 647-PLF1E6R8MCL2
n/a	C14	see Left PCB - C12	see Left PCB - C12
C14	n/a	10 μF 35 V 105 °C ↨ 8 mm ∅ 5 mm RM2 Nippon Chemicon KMA (wet)	see Left PCB 1997 - C12
C15	←	47 μF 25 V 105 °C ↨ 7 mm ∅ 7 mm RM2 Nippon Chemicon KMA (wet)	47 μF 35 V 125 °C 1000 h ↨ 6 mm ∅ 6.3 mm RM2.5 Panasonic SEK (dry) ‎Part Nr.: ‎35SEK47M‎
C17	←	47 μF 25 V 105 °C ↨ 10 mm ∅ 7 mm RM2 Nippon Chemicon KME (wet) ⚠ Bi-Polar	47 μF 25 V 105 °C 1000 h ↨ 12.5 mm ∅ 6.3 mm RM2.5 Nippon Chemicon UEP (wet) ‎Part Nr.: ‎UEP1E470MED‎ Alternative: ↨ 11.0 mm Rubycon NXA Part Nr.: 25NXA47MEFC6.3X11
C18	←	See C18 ↑	See C18 ↑

1991 EU and 1997 JDM AT use the same capacitors at the same places (except C12 on the 1997 JDM AT left PCB) but about half of the identifiers differ. The part numbers in above table can be used for ordering at digikey, mouser and potentially other sources, too.

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

Assembly
The most dangerous part is attaching the PCB to the housing by means of the silver/bronze-coloured screws. As mentioned before, they are responsible for the electrical connection of the gauges to the PCB.

Warning
The threads are located inside the gauges and easy to twist-off. Hair-thin wires are attached to them. If a twist-off happens the wires are very likely to snap. This can be repaired but a very delicate task and replacement gauges are expensive. It's best to follow these rules:

• Insert 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 maximum.

After all this has been accomplished the unit can be installed back into the car for further testing.
Check if all lamps light up, backlight is working, RPM and speed values are correct. Please ensure that the displayed speed is not below the actual speed as this is illegal in most countries.