Nav light repair

[requiem]

I've a green side light that isn't lighting up as it should, and wanted to get some advice before I start taking things apart.

The light in question, I believe an Attwood series 3500:


My assumption is that there's a baseplate and gasket screwed to the deck, and that the Phillips-head screw is merely holding the stainless steel cover in place.

My plan is to check for voltage where the wires meet the light, but I'd like to know what I should have on hand to ensure proper waterproofness when re-assembling.

Similarly, are there any other gotchas I should be aware of? So far as I can tell there's no access to the wiring from the interior, at least not without tearing apart bulkheads.

Thank you!

Edit: as per usual, just after hitting "post" I think I found the documentation I was looking for: http://old.attwoodmarine.com/userfil...ht-install.pdf

[goboatingnow]

As Dave Jones says ( eevblog) ( adopt a broad Aussie accent ) “ don’t turn it on , take it apart “

[CaptTom]

Could be a burned-out bulb. Have a replacement handy.

Could also be corrosion on the contacts. Have a small file handy. And some dielectric grease.

Better still, buy a pair of LED light fixtures. You'll never change a bulb or clean corrosion again. Be advised that just replacing the bulb with an LED bulb isn't a good idea. The fixture was designed to display the correct light pattern ONLY with the bulb filament in exactly the right spot, and you'll still have corrosion to deal with.

[Sailor Sailor]

I replaced mine with LEDs. Your description of the structure is accurate. Make sure you use good heat shrink butt connectors.

[Rumrace]

No ox grease the socket and you can check voltage at the socket. The replacement 12V LEDs have a driver circuit on them. Some are still junk with slow pulse rates but they will outlast any incandescent lamp.
There are constant current power supplies and dedicated commercial grade LED manufactures.
One of the best is in US and the other the German division of Phillips. These diodes have made it to the marine industry. The leader Samsung in automotive and traffic lighting are soft at marketing all their products. Their grow lighting interior lighting is amazing. They have become dominate in automotive from sheer quality of whole systems. There are some pretty decent import lights. They were developed domestically and produced apparently to spec in China which is no easy task. Specifically for Marine commercial applications with smaller gear fitting our personal craft. 24V or 36V circuit for the ships lighting can solve some issues.
Marine lighting is a safe place to start your learning curve. The biggest mistake I’ve found in my used boats is folks adding systems and picking up power of another system. Make a point to clean every socket or connection and a thin coat of no ox grease. Tinned wires in the connector is something I follow. There are good arguments not to but it stops the wire from degrading in the connector.

[requiem]

Thanks all!

These being LED fixtures already, I expect I'll have to cut the existing wires and redo the connections just to be able to check for voltage.

Blue Loctite on the cover screw, I assume?

[5BTM]

I usually start with that; it has woken up a few connections and switches on my 79 vintage CS 27.

https://caig.com/deoxit-d-series/

https://caig.com/product/deoxit-d5s-6/

The PO was a lightbulb changer but the wiring was too much work.

[requiem]

Thanks all! I happened to find the very last same-model replacement on clearance and we swapped it in. The LED phosphor on the old light had brownish spots instead of the typical yellow one would expect.

I was less pleased to note the previous butt connector hadn't been heat-shrunk.