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940 headlights very dim with age

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Old Jan 15th, 2020, 21:29   #91
Laird Scooby
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Originally Posted by bluebrickrick View Post
My guess Dave is the automotive bulb makers are using as many common LED's as possible (I assume they are surface mount devices) and modulating the pulse width according to the required 'wattage' in any particular assemblage hence the Brake or Fogs having a visible pulse rate compared to the rears which would seem to be on a higher frequency.

I don't think there is likely to be a problem with the reflected light, it is the line of sight which is intense enough to cause a retinal effect, so not a problem to vehicle driver, just those seeing their bulbs !

Sadly I'm of an age to remember when Maplins catalogue was a double A4 Roneo'ed sheet, likewise the 'Cat' of a certain Mr Ken Whiston of Stockport, last time I visited New Mills for something, had I known it was to be the last I would have filled the boot to the headlining I particularly miss his black heat joining drive band material, nothing since has stood the test !

As you say Maplins customer base has to have changed but they were the only outlet where newcomers to the sort of interests requiring raw components could go to view and pick & choose, however, their business model allowed for such apparent anomalies as having two expensive real estate stores in Norwich, neither maximising potential - I and no doubt other 'dinosaurs on borrowed time' salute both firms for their service while trading and mourn their loss.

Rick, off 945 carcase picking this afternoon
With good LED headlamp bulbs Rick, the most common LED is the Philips LumiLED ZES LED, very small but powerful and can be arranged with 2 or 3 others to mimic the original tungsten filament of the the halogen bulb to give the correct beam pattern.

For the rears and sidelight/indicators, most of the time you're right, they use fairly generic LEDs of differeing designations and Lumen outputs. By using the right number of them and the right brightness (in Lumens = Lm), it's possible to recreate the right sort of light output from the indicator, sidelights, stop, tail, reverse lights etc.

The normal LEDs that we use for other things have a Vf (Forward voltage) of about 2.4V but most of the white ones for LED bulbs (and also the orange and red ones for automtive lamps) have a forward voltage (Vf) of 3.6V - multiply that by 4 and you have 14.4V so often the clusters of LEDs for LED bulbs are arranged as 4 LEDs but sometimes they will do 3 (10.8V) with a series resistor as a safeguard against voltage spikes on the system.

Generally speaking, you get what you pay for though, the correct LED headlamp bulbs aren't cheap but 6 years on are still just as good as the day they were fitted, no loss of output and an added bonus is the headlamp lenses stay cleaner!
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Old Jan 18th, 2020, 18:20   #92
Laney760
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Laney,
Pull the plug for the dim dip. It's in the drivers footwell, a silver looking box with a white 6 pin connector. The relay is bolted to the chassis as it gets hot.
That's the problem. That will solve it.
I have just found this post, cheers!
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