Castell Mawr - A joint GWR/LMS route

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The old ways are often the best, I moved on to the next mystery box and found a string of 100 grain of wheat bulbs, at 3v they give out a soft yellowy gas light glow, and they are actually smaller than the LEDs just right for my platform lights. Have you thoroughly scraped the leads on your LEDs they often seam to have some sort of skin over them, you can solder to them ok but you'll do it a bit better if you've exposed the raw metal. It may be down to oxidation of the wire, whatever it is.

[Dad-1]

John,

If it was easy enough and I could afford to change to filament bulbs I would.
I do believe they are more easily adjusted for output than LED's that need that
trip voltage (Abt 2.7V?) before they work and are then already too bright !!

The one disadvantage is power consumption and heat. One melted the plastic shield
used in a building to disapate the light into a room glow.

Geoff T.

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GoW.s run at well below maximum voltage don't produce that much heat, I think the wiring is proportionally that much thicker that it acts as a built in heat sink.

[TimberSurf]

Matching a resistor to an LED as per the calc will give 100% brightness and long life.
For us modellers, modern LED's are too bright.
Increasing the resistance will dim the light, but only when using one resister per one LED, as soon as you string LED's together (Series) or group LED's with one resister (Parallel) then the troubles start!
LED's brightnes is dictated by current and can be controlled with a current limiting circuit for best results. Using a resister in series is actually a voltage divider and is a poor (electronic) method to limit brightness (supply voltage will still effect it).
Quite simply the best method, is to set the resister and brightness to manufacturers specs, then control the brightness by dimming with PWM (pulse width modulation)
This can be achieved relatively cheaply, maintains the long life and gives ultimate control of the brightness desired.
Dimming Guide

P.S. also works well on incandescent bulbs!

[Dad-1]

Must read that later TimberSurf .........
Dimming Guide, for me that's lack of sleep, was up last night wandering around at a silly time.

Anyway the first board is 100% working even if 2 are brighter. Today before I went looking for a
club member in hospital I had a go at board No.2. Here you can see the dead light just above the
57XX cab roof. Did a couple of resistor changes, but still not getting steady light, must find another
220R as a final try.
Anyway a picture to lighten (Pun) my mood. Thought I'd swing the water bag to a tank filler.



I believe these LED's are inconsistent in demand. Put my 4.5V power onto the negative. Then clipped
positive onto the resistor leg, up stream, result a steady bright LED. Clipped onto the resistor down
stream so light power came through the resistor, result a dull, but flickering LED. The flicker couldn't
have anything to do with my soldered joints, so my conclusion is that this LED is being starved of power
with the resistor being too high a value - I think this was a 470R to keep brightness down. How come
others work with 1K ??????

Geoff T.

[heda]

I'm not able to give any advice regarding the rogue led but if it's any help you can use a emote dimmer to control led brightness.

https://www.ebay.co.uk/itm/Mini-12V-3-K ... 28E9i4-i5Q

At worse could you put a workman on a ladder replacing the bulb.
Dave

[End2end]

I'm not able to give any advice regarding the rogue led but if it's any help you can use a emote dimmer to control led brightness.
https://www.ebay.co.uk/itm/Mini-12V-3-K ... 28E9i4-i5Q

I bought some of those. Good iem!

At worse could you put a workman on a ladder replacing the bulb.

Great idea for a cameo.
Thanks
End2end

[Dad-1]

While both TimberSurf and E2E's suggestions are fine I'm working
on a 'holding' job here. I had already bought 3 identical lights to replace
the failed items.

Two responded to a change from a 1K resistor to a 220R the third light
didn't want to play so today I've removed and fitted a replacement.

The removed light works fine although a little bright with a 4.5V supply.
It will not work with ANY resistor in the circuit ????? How's that ??????
Yet it did and so does the replacement .......

Geoff T.

[Dad-1]

What a Nice Day !!

Had the last boards out today to clean tracks and check electrics.
Also replaced the Diesel tank that had fallen away from the council roads dept yard !!

Unashamedly bumped up the listings to easily tie in with my exhibition posting !!

Geoff T.

[Admin4]

I can see from page 1 that your side boards are 40” in length, but with the unconventional end boards I can’t quite work out it’s full footprint size.

[Dad-1]

Hi Dave,

There never was a definitive measurement because while the main straights were made up of
6 of the 20" x 40" boards the corners were eventually made up from surplus ply that was laying
in Jamie's bedroom. Something that was causing some aggravation at home.
They were cut and re-joined into their odd shape to link between the two sides. Actually one of
the intrinsic weakness of overall design.



By dropping one end I obtained the height that I always wanted.



I wish I'd had longer legs on the main boards allowing for an even greater drop to our river.

It still gives more or less what I wanted.

Geoff T.

[Dad-1]

Always for longer than average trains to run.



Sidings in preference to a non-scenic fiddle yard.

Geoff T

[Dad-1]

Well Castell Mawr is no more, well not in my hands, collected today.
Not destroyed but given away to Jamie who was in on the build when still at school.
Jamie is now 30 & married with Charlie a wee toddler.

Am I sad, not really as the major fun was designing and building.

Geoff T.

[Phred]

Good that it will now continue to be enjoyed by Jamie and Charlie.