I'm working on one of these sets for a mate. He purchased it second hand fitted with an ESU decoder and PIKO internal coach lighting boards.
I was surprised to find that the lighting board leds are all wired in parallel. A quick check revealed a current consumption of about 12mA per led. As each coach has six leds and the two power cars three each the total current draw can become significant once extra coaches are added to the set. For example my mate has two extra coaches in addition to the set of two power cars and a coach giving 24 leds. The function output of the ESU chip is rated at 250mA, not enough by my maths!
My solution was to remove two of the resistors, cut the tracks in a couple of places and add a couple of wire links to each of the circuit boards, ending up with the three leds in series. This reduced the current per board of three leds from 36mA to 8mA.
The led brightness wasn't unduly reduced.
I suspect most readers who feel confident performing this modification would probably make up their own lighting boards as the Piko ones aren't cheap. However I hope this post gives some guidance.
I was surprised to find that the lighting board leds are all wired in parallel. A quick check revealed a current consumption of about 12mA per led. As each coach has six leds and the two power cars three each the total current draw can become significant once extra coaches are added to the set. For example my mate has two extra coaches in addition to the set of two power cars and a coach giving 24 leds. The function output of the ESU chip is rated at 250mA, not enough by my maths!
My solution was to remove two of the resistors, cut the tracks in a couple of places and add a couple of wire links to each of the circuit boards, ending up with the three leds in series. This reduced the current per board of three leds from 36mA to 8mA.
The led brightness wasn't unduly reduced.
I suspect most readers who feel confident performing this modification would probably make up their own lighting boards as the Piko ones aren't cheap. However I hope this post gives some guidance.
