Instrument cluster

[Sneaaky]

Hi, I have a few questions about the instrument cluster.
I've already repaired the EL backlight and needles. After reassembling i wanted to test it. I assumed each gauge would be grounded through the metal housing, but that doesn't seem to be the case. Do I need to connect the wiring harness to test the cluster on the bench, or am I missing something?
My second question is about the gauge needles. I've already painted them, but they don't look the way I wanted. What kind of paint shuld I use for them? I've tried a few different ones that i had laying around, but none of them were good enough.
My third question is about calibrating and testing the gauges themselves. I know they all work, but I'm not sure if they're reading accurately. I'd really appreciate any information on how I can properly test and calibrate them.
One last question: is it possible to install the entire fully assembled dashboard into the car as one unit, or does everything need to be installed piece by piece?

e?

 

[Sneaaky]

Have a look here...

I know this video very well, at first it was helpful but now, after all cleaning and painting, it is not enough

 

[twecomm]

Try having a look at this video. On your comments.. the outer round portion of each gauge is to be at chassis ground. That's needed for the el lighting of the gauge background. On the gauge movements, alt, oil, temp, fuel, neither threaded terminal is grounded.
Oil, Temp and fuel gauges get a pulsating 5-7 volts from the gauge voltage regulator located inside the fuel gauge. That pulsating voltage is on one terminal of each of the gauges mentioned. The other terminal goes to the respective sender unit that operate as a variable resistor to ground. This change in resistance controls the small current thru the gauge to move the needles. Speedometer is strictly a mechanical driven device. The Tach is driven by tach sender pulses derived off the ignition coil.

 

[RedBeard]

Sent you a PM.

 

[Sneaaky]

I understand how it works. My problem is that the external gauges (oil, water, fuel, amp) don't have a ground connection through the main housing. Each one is isolated by a spacer between the gauge and the main housing, along with the terminals. On the other side, where the nuts are screwed on, there are also insulating washers, logically. This causes a grounding problem, and it looks like in the picture.

I don't understand how it was grounded before. I'm clearly not the first one here, so I don't know if everything is in place. I can connect the gauges housings with wires and they will light up without a problem, but I'd rather fix this problem than add unnecessary wiring harnesses.
As for the voltage regulator, mine was faulty and I converted it to an external one.
I managed to repair power pack with replacing damaged capacitor with a diffrent one.
My tachometer is acting irregularly at the moment, but I think it will fix itself after few tests.
I haven't checked the sender unit yet, but I don't think there's anything complicated inside.

 

[twecomm]

The dish shaped parts of ALL the gauges have a metal base and are coated with the electroluminescent layer and overlaid with the black black decals, all the metallic dishes need to be grounded to work and should be attached to the pot metal casting. The hi volts AC from power pack ( white wire ) gets connected to daisy chain the hi volts to each slide on terminals on the dishes for them to light up as the inner gauges your photos already do. The outer metal chassis of the power pack is grounded as well, bu you know that already.
The screw like terminals on the rear of the gauges, alt, oil pressure, temp and fuel, are insulated from the gauge housings with the phenolic washers, DO NOT get ground connections at the gauge cluster. one terminal of the oil, fuel and temp gauges gets the output of the gauge voltage regulator (Aprox 5 volts) on one terminal and the other terminal goes thru the bulkhead connector to the respective senders. One side of each of the senders is grounded to the engine block. There is a separate slide on connector on the gauge housings that apply the hi volts for Illuminating the gauge orange needles. If any of the EL items are shorted, as is common with the gauge needles, it will shut down the power pack.
In case of oil and temp gauges, the sender bodies are grounded via the screwing into the engine block. In the case of the fuel sender to the chassis of the car at the fuel tanks sender. The alt meter goes thru the bulkhead with one side battery and other side to the alternator output. It does not use a ground.

 

[chrger1967]

I found that the EL in my tach stopped working. Can those be bench tested?

 

[twecomm]

Yes.. Ground the rear metal that supports the gauge dish to the chassis of the power pack which is ground ( -12 V. ) Apply the hi voltage ( aprox 240 VAC ) off the white wire of the power pack to the push on terminal stud that's on the dish edge, then apply + 12 V to power packs orange wire. The EL needle in the tach has a separate push on tab connection on the rear can of the tach gauge that supplies the hi volts to the needle in the gauge. It's possible that where the slide on contact tab connects int the EL layer of the dish could be intermittent or no longer making the necessary contact. Careful of the white Wie when power pac is active as it will shock you...

 

[Sneaaky]

I took the gauges apart again and repainted the needles. They look better now, and I think Ill leave them as they are. I used concentrated candy paint mixed with clear coat about 1:1.

I also solved the grounding issue for the EL backlighting. My cluster was missing the small copper contact strip/plate between terminals like the one shown in the photo.

Now I just need to know one thing. If I fully assemble everything into the dashboard, will I be able to install the complete dashboard into the car afterward? Or is there anything that will prevent it from being installed?

 

[twecomm]

If you are confident that all the gauges and gauge voltage regulator work properly you can install it. DISCONNECT THE BATTERY before you re-install it.
However.... I would suggest that you carefully inspect the alt or (amp) gauge first. The way it works is.... Inside, there is a brass bar sitting on 2 phenolic spacers with shoulders. It spans the 2 screw studs coming out the rear. The direction current flows thru the brass bar ( Shunt) will create a directional magnetic field that deflects the gauges needle which has a tiny magnet inside on needle's movement. Battery getting charge current from alternator = gauge showing "C". Battery being discharged by loads shows = "D". When centered, the charging current is at an equilibrium with cars battery and loads are being powered mostly by the alternator, not the battery.
The end, or head of the studs, pass thru the internal brass bar MUST be making perfect connection to the screw heads. The screws then pass thru a fiber spacer with a small shoulder that will separate the screw insulating it from the cans housing. The rear screws is where the 2 heavy gauge wires from battery and alternator will attach. Both screws are insulated from gauges metal can by the small shoulder on the spacer and a fiber flat washer on the stud at the rear of the can. The fiber spacer and fiber washers "sandwich" the can maintaining insulation FROM the can. It's most important the studs heads are tightened sufficiently so that the stud head gets pulled tight against the brass bar. At the rear, there should be a fiber flat washer on the screw first, followed by a metal flat washer and then nut #1. The nut #1 should be sufficiently tight to compress the washer stack tightly, but no so tight it damages or cracks the fiber washers. .
When installing the lug and final nut # 2 that will compress on the lug on top of nut #1 and lock washer, it suggested to use a small wrench to hold nut #1 in place the when you tighten the final nut #2 to maintain the lug connection. If lugs and and wires for this alt gauge are all proper and tight , and cars electrical system has not been modified you should be ok and safe to re-attach battery.
The cars original wiring is fine as long as it's in decent condition, no green corrosion at the crimped connections and bulkhead connections are proper and clean. If your car has modifications to the car that all require additional battery current, those "non factory" loads may exceed the ratings of various wire gauges which is why some folks bypass the alt gauge. But if your cars original and un mollested electrically, the factory alt gauge and wiring is just fine.