Does anyone have any experience with the LED lighting that North Hollywood Speedometer does? Especially, how does it compare to just buying the LED bulbs that are avaliable as replacements?

The price that they charge to convert the gauges is quite a bit more than just buying the bulbs. I'm just wondering if they do that much better of a job or not.

Anyone?

the LED bulbs dont spread light outward, so you'll see concentration of light right where the narrow beam hits the front of the guage (or guage edge) and a lesser degree of light outside of that narrow beam.

I have heard that the North Hollywood conversion is much more in-depth than just replacing the bulbs...I gather that they revise the lighting system in those guages.

b

Not cheap, I called a while back. To do 3 914 gauges it was around $250.00.

When I talked to the NH Speedo guys, they said that their system was dimmable, which indicates some sort of controller. I've only seen good work from them, their conversion should be worth it, if you've got the $$$.

Eric

Several people swear up and down LEDs are dimmable w/o a "controller" (basically a PWM circuit). I'm not a EE, and I've not fooled around with LEDs enough to know for certain, but this MAY be true, even though it goes against what little electrical theory I know.

Some places have LED "bulbs" with lenses that are designed to spread the light "sideways", rather than just point in one direction. Some of them are fairly cheap. www.superbrightleds.com is one such place. No affiliation or even experience with them, just pointing out an option.

Somewhere, I think maybe on a 912 board, someone showed the insides of an NH Speedo modified gauge, and it looked like they used quite a few LEDs, and painted the inside of the gauge housing white to reflect the light around better.

Personally, I prefer the warmer, yellowish light of incandescent bulbs as dash lights. LED bulbs are great for taillights, brake lights, turn signals, the lights I can't see in the car. Dash lights I have to look at, so I want them to be pretty. The current draw on them is pretty small (2-3W per bulb, usually 1-2 bulbs per gauge, so on a 914, 6 normal bulbs, or 12-18W total, or a little over 1A). Blue LEDs are too blue, white LEDs are still too blue, green LEDs are just ugly, and red LEDs are usually too dim.

NH does quite a conversion on the instruments. I talked to them and it sounds as if they repaint the insides of the instruments and add a line of LEDs, not just the one bulb. I replaced my bulbs with the LEDs myself, and the light is a more bluish white than the yellowish color of the original bulbs, but it is not much brighter and does not dim down very well - it seems to go from bright to almost out.

If I had the extra money laying around, I'd go with the NH conversion, but it is expensive.

I bought those bulbs as well, off ebay. I took them out 2 minutes after I put them in. Not any brighter, the clear ones are blue when illuminated, and I didn't even bother trying to dim them. $20.00 wasted. I have heard good things about North Hollywood, and heard bad, and had bad with Palo Alto Speedo.

Yeah, $250 is what they quoted for all three gauges. This is how they describe the conversion:

"All instruments have to be taken apart and LEDs are installed internally at various locations. This does not alter your wiring set up. "

I'm already going to send all of the gauges to them for other stuff, like putting a gas gauge in place of the boost gauge on a 930 tach, so now would be the time to do it. I personally don't like the yellowish bulbs that are there now. Too dingy for me, and I can barely read them at night. I guess I should have tried just the cheap LED bulbs before I pulled the 1.7 out. Too late now.

Thanks for the info, if I do it, I'll let you know how it turns out.

QUOTE

Several people swear up and down LEDs are dimmable w/o a "controller" (basically a PWM circuit).  I'm not a EE, and I've not fooled around with LEDs enough to know for certain, but this MAY be true, even though it goes against what little electrical theory I know.

If you don't mind, as an EE, I'll weigh in here... Here's the deal with LEDs -- somewhat simply, an LED's light output scales with the current that passes through it -- more current = more light. So far, pretty simple. The complexity comes in the exponential current to voltage curve of an LED, which effectively means that if you apply more than about 1.5 to 3 volts (the exact value varies), then you start to reach the "vertical" section of the curve, current starts to go to infinity, and the LED turns into a DED (Dark-Emitting Diode).

So, getting to the point, to run an LED properly, you need to be able to precisely control the current passing through it. At its simplest, this can be done by just putting a resistor in series with your LED and the 13.5V charging system in your car. You would choose the value of the resistor so that the current passing through the diode would give you the brightness you need.

You could dim the LED in a couple of ways:
1. By replacing your fixed-value resistor with a rheostat or potentiometer.
2. By using the fixed resistor and by switching the 13.5V power supply on and off. During the "on" times, the LED's brightness would be determined by the current established by the resistor. And during the "off" times, the brightness would be zero. Don't want your dash lights to flicker? Well, just increase the switching frequency. At some point, say about 100Hz (100 cycles per second) or so, human beings cannot detect any flicker. The bright "on" times sorta blend in with the dark "off" times, and the perceived result is somewhere in the middle between the two extremes. Exactly WHERE in the middle is determined by the time-ratio of ON vs. OFF. Want 99% brightness? On-time of 9.9ms, off-time of 0.1ms. Want 50% brightness? On-time of 5.0ms, off-time of 5.0ms. Etc. Pretty straightforward.

I think the more significant question is: WHY?
LEDs have only 1 advantage in this application -- they might last longer. (And even that isn't a sure thing -- to get the longevity, you'll need to keep your current low.) I'm not sure that advantage is worth the additional cost and less-pleasing light.

The way I understood it, most LEDs have such a non-linear brightness to current curve that just using a pot usually nets you: BRIGHT................dim..off. With no change between BRIGHT and dim. With PWM, you can get a more linear curve, much more like incandescents.

I agree there's not much point to all of this. I suspect most people like LED taillights (where the current savings can be more significant), and want LEDs for everything.

I love the LEDs. I bought the blu for my car and modified all of my needles to white so that they would show up (blue and orange are not very complementary). My gauges were also white on the inside (many of the older ones came that way.

Then again, I do do gauge service form time to time. I am sure some of my patrons will chime in withtheir views on this.

$250 is fair for all gauges because parting them is a bitch and there are parts involved. If I were to do this again, say in the summer, I would charge about $60/gauge + parts. Only a bit cheaper, but we will see.

The gauge pictured has my extra light bung added where the annoying dark spot is at the apex of the tach. What do ya'll thinK?

I got the LEDs that had the wider beam so I would have better spread. I don't think that narrow beam would work.


Here is the back of the modified gauge.

were do you get the wide spread bulb in blue?

Kinda a long story, but I got mine from Qarl who later gave his LED biz over to some kid tha was selling on the bird board. If you search around you should be able to find them, though. Qarl made sure to get the wide beam if I am not mistaken. They were like a buck each. I bought like 20. I have the white ones too. I like to change with my moods