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Nerdy question for Rally boys

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Years ago when I was rallying I remember the dash lights for secondary instruments having what was known as a "p" light. These were tiny alloy bodies with bulb inside set on a crescent shaped mount the bulbs could be rotated and provided a down light over the instruments. 

These were typically used on Helicopter cockpit instruments but 24v, wondering where to get equivilant 12v bulbs these days. These things are very rare I undersatnd and cost sack loads of cash.

Anyone recall with more info.


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I think you must mean 'pea' bulbs Rod - so called because they are about the size of peas. They are really LES (lilliput edison screw) and are still readily available, e.g:


The matching bulb holders:


Is that what you mean or are you after the whole lamp?

Edited by RobH
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I recall Graham Robson telling me some 50 years ago that these very small lampholders were used in aircraft, and that they were rarely found - so I should look after them!

To direct the light through the slot in one side of the cap, the cap of the holder is rotated (not the bulb) so that its window points as required.  The bulb has no screw thread - it slides into the holder and is retained by the cap.

In my car, near one of these lamps there's a bulldog clip to hold a small sheet with route directions - excellent at night.  I have to admit that more recently I have used my Garmin, but the original system served me well for decades.

In the photo, one of these lamps is visible on the circular plate, at 4 o'clock to the bulldog clip and at 8 o'clock from the orange lamp.

Ian Cornish


Edited by ianc
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I had not realised that a simple post that I thought would be difficult to get an answer would create such knowledge and variances. The forum wins again!!!

My dash is quite simple only Halda Speedpilot, stopwatches, butler map light, map and pencil clips and additional light and horn switches. No electronic gismos thank god.

I have a quantity of the original type ad spare bulb holders and the friction positioning is a bit iffy but if good enough for aircraft instruments then so be it.




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Had a look today at the very small lamp on my dash - it's so long since last I removed its top that it has become stuck!  It's still working and I will have to try loosening it sometime.

However, in the boot I found a stock of some 8 spare bulbs in a pack labelled SCH 725 12V/0.1A.

It appears that SCH may no longer exist, but there's a photo of the bulb on silicon-ark.co.uk/725-12V-100mA (out of stock!) and ellison-electronics.com lists it (without photo) and states 11 in stock.

Ian Cornish

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