I had two attempts to illuminate the speedo with UV LEDs. The attached photos show my first, less successful setup. I used 10mm diameter LEDs which were rather large for the space available but more significantly they each produced a very narrow angle of light which resulted in three bands of illumination around the dial.
For my second attempt I used 5mm diameter LEDs with a wider angle of illumination. They were flat topped (see last photo) rather than rounded, which allowed them to be positioned closer to the black glass. There is still some banding of the light but less than with the 10mm LEDs. It might have been better to use four LEDs but I am happy with the result using three.
Unfortunately as it was some years ago,I cannot now identify the exact LEDs I used but there are many alternatives available online. I would recommend using 5mm diameter high Brightness UV LEDs. These look very similar to the ones I used, eBay item number: 261319713773
soldered the positive leads together and connected them to ground, (my car being positive ground). The negative leads were connected to the original connector supplying the tungsten lamp holder which I removed. I shaped the aluminium alloy strip to hold the LEDs securely against the black glass and used some plastic foam to help stabilise things. Finally I covered the hole where the lamp holder had been removed with some electrical tape.
Hope this is clear enough. If you need more help please come back and ask.
Regards,
Andy
Having trouble posting the images I will try later
