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Lighting Trains

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On 11/26/2017 at 2:35 AM, gavino200 said:

 

Yes, they're definitely not caps. I could have answered that just by thinking about my flicker problem. 

 

The two SMDs on the right are resisters. I don't know what's going on with the two components on the left. They look like transistors. I'm guessing it's acting as a rectifier. Is that the right term? To block the reverse current from the DCC AC.

 

IF8ipXs.jpg

 

 

I think I'm finally going to do this. I actually ordered one of those SMD resistor assortment books from China around the time I posted this. I didn't understand about there being code numbers for different physical sizes of resistors. I focused just on the Ohms. The book I received was full of minuscule 0402 resistors. I sort of abandoned the project. 

 

This time I know what size code I need - 1206. (3.2x1.6mm). I'm not getting an assortment either as they contain tons of values that will never be useful for trains. I'm just going to get rolls of a few different values that I think I'll use.

 

Currently the TORM has two 330 Ohm resistors and they're brighter than the sun. 

 

I was thinking of trying a 1k, 1.5k, 2k, 3k, 4K. 

 

Anyone want to guess what value will work? I know, I could set up a trial rig with a potentiometer and then read the resistance, but you can only tell what's right with the train coach closed, and that would be difficult to wire up. I think it would be easier to just play around with it until I get it right and then just use the same value to fix all my TORMs.

 

When I'm done with my TORMs I'll probably just move to using regular LED strips and rectifiers. 

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On 12/17/2017 at 11:19 PM, Kiha66 said:

Yeah, the old version of the kato lights was pretty bad, but the LED one works very well.  The brightness seems to be pretty good too, but some cars need the floor painted to tone down the shinyness.

20170930_115725.jpg.17f534c57fc87a1f0d45219d2351041d.thumb.jpg.aa4ba3b80086b7ebd202f877ec0480ab.jpg

23472949_1817778518251288_4134561236316162139_n.thumb.jpg.f065d0461a238c77ef5aafac20f48911.jpg

 

I'm still amazed by this result. One of these days I'm going to buy one last Kato lighting kit, to try for a result like this!!

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1 hour ago, gavino200 said:

I'm still amazed by this result. One of these days I'm going to buy one last Kato lighting kit, to try for a result like this!!

 

I really like them, they seem to have the brightness just right and the new version's light guide does a great job spreading the light evenly over the whole car.  I hear that a touch of tamiya clear orange on the LED will create a good incandescent effect too, so I plan to test that out in the near future.

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2 hours ago, gavino200 said:

Currently the TORM has two 330 Ohm resistors and they're brighter than the sun. 

I was thinking of trying a 1k, 1.5k, 2k, 3k, 4K. 

Anyone want to guess what value will work? I know, I could set up a trial rig with a potentiometer and then read the resistance, but you can only tell what's right with the train coach closed, and that would be difficult to wire up. I think it would be easier to just play around with it until I get it right and then just use the same value to fix all my TORMs.

With 12V, a rectifier bridge and this many leds 660 ohm sets around the maximal current the leds tolerate. Normally one would use 1k or 1.5k, which means 570 ohm x  2 or 720 ohm x 2. In your case. you might want to leave one of the 330 ohms in place and add 1k or 1.5k, giving you 1.3k and 1.8k. If you go above 4k or 5k, the leds might not turn on at all or get lit up quite uneven. (there is a minimal turn on voltage and current for each led based on the material it's built out and it varies very slightly within the same batch, pretty much like resistor values)

 

I would also add an extra buffer cap or two between the rectrifier and the resistors. (onto both sides of the small filter cap sitting vertically just right the rectifier chips)

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8 hours ago, kvp said:

I would also add an extra buffer cap or two between the rectrifier and the resistors. (onto both sides of the small filter cap sitting vertically just right the rectifier chips)

 

In my hands that would be much more difficult than just switching out components on existing pads. I'd be sure to ruin an unacceptable percentage of them. I'll probably experiment with that at some stage though. I don't have any of these tiny caps. I'll have to do a bit of research to avoid buying the wrong size and type. 

 

I'll order a few rolls of resistors tonight. I'll let you know how it goes. 

 

Thanks kv.

Edited by gavino200

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One of  the tricks is CA glue. You put a small amount on the bottom of the component between the pads with a toothpick. Then glue it on. Wait till it dries and then touch the tip of the iron to the top metal pad part of the component and then the thin solder with the no clean rosin flux inside towards the bottom, near the board  and it will solder easily. You can solder two pads together too, so by leaving the original cap there, gluing the new ones next to it and soldering them together, you don't have to position the new ones too carefully just put them next the installed part.

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