Weak light from fiber optic cable

[MikeB]

In the category of "it's always something", my new fiber optic gear indicator cable doesn't transmit enough light. My old one (which I accidentally pinched) was blindingly bright if I looked directly in to the end, but the new one has a weaker beam that essentially does nothing to light up the pointer and indicator. I just now confirmed the weak light with a bench test using a very bright LED flashlight on one end. Even the old cable with a kink worked better!

So here's my question: Are these cables created equal by the same supplier or are some better than others? I got this one from LMC a few months ago, so I'm probably SOL on getting a credit.

Probably going to order one from GMCPauls, but just wanted to hear your comments.

Also, I am using 71-72 components.

[MikeB]

Just noticed on Classic Industries website that 67-70 and 71-72 cables are different. The cable I have looks to be a 67-70, not that it should matter in its ability to transmit light.

As I said above, I am using 71-72 pointer and indicator. And here's what the lamp holder looks like. Are they the same for 67-72?

[dmjlambert]

There's probably a whole lot of those in junk boxes in the garages of a lot of members here, since everybody is so wild about tilt steering columns. This sort of item is what I would post a want-to-buy ad for in the parts section, and that's why I'm usually a paid subscriber here. For some things are hard to beat the original and the originals are often in good shape. I'm also curious about what the members with experience on that reproduced part will say.

[MikeB]

You're probably right about there being lots of stock instrument panels lying around. I almost bought a Dakota Digital, but prices had gone up considerably since I looked at them 2-3 earlier. Ended up putting a voltmeter and electric oil pressure gauge from a square body in mine, along with LED lamps.

I think the lamp holder (bulb socket) that the cable plugs into is OK. Since I think my cable isn't transmitting enough light, I just bought another one from GMCPauls. This time for 71-72. Guess we'll see what happens.

[chewychevy67]

If you installed led bulbs that may be your problem. They have such a focused light that it would have to be pointing straight downtrend wire to get proper lighting which these holders do not. They hold it from the rear of the bulb.. Incandescent shines everywhere and relys on reflection.

[dmjlambert]

What I meant is there are a lot of fiber optic cables left over from people replacing the non-tilt steering column (which requires the fiber optic cable) with a tilt steering column (which uses its own light bulb in the steering column).
chewychevy67 has a good point, you didn't mention if you changed your instrument cluster light bulbs to LED. In most cases, the light bulb should be standard incandescent for the fiber optic cable to pick up the light very well.

[MikeB]

Originally Posted by chewychevy67

If you installed led bulbs that may be your problem.

The dash bulb is an LED, but it worked well with the old cable when it was partially kinked. I did try an incandescent bulb, but it transmitted even less light thru the cable.

Each LED "lamp" is composed of three LEDs on a circuit board -- one on each side, and one on the top. And the fiber optic cable end is aimed almost exactly at one LED on the side.