GRJ's Original DIY Constant Current PAX Car Lighting Module Files

The LM317 is a pretty robust part, it's not like you're typical delicate IC.

@gunrunnerjohn posted:

The LM317 is a pretty robust part, it's not like you're typical delicate IC.

Too funny, my initial thought was "when did the Illinois Central become delicate"?

Paul

Digikey cart share

I don't know how long Digikey retains a "shared cart".  Above link should get you to a starting point for the parts list for this project including the original and alternate capacitor (choose 1)- presumably at some point the original capacitor will return to in-stock status and it's a bit less expensive.  The idea is you simply click on above link and it loads your shopping cart for a quantity 1 order.  Edit the quantity for each item.  Who knows if this saves time but I've always thought this was a neat feature from DigiKey.

@stan2004, thanks for the link.  Just getting ready to do another 10 pax cars.

would this board work in an engine? I have a sunset model that I'm installing a DCS upgrade kit.

Thanks for any help

If you want LED's from a PS/3 upgrade kit, just use a 220 ohm resistor in series with the LED, no need for any drivers.

It’s two rail. Would that work?

By the time it gets to the headlight, it's always the same polarity.  Just make sure the PV (purple) goes to the anode of the LED.  The resistor can be in either lead.

ok. That makes sense. Thanks John.

@TedW posted:

The pcb can be ordered here(in sets of three)from Osh Park:  DIY-GRJ-JWA Passenger car lighting PCB  I don’t have an off shore link for the pcb, but others do.  You will need to set up an account to order, but once on this site that will be straight forward.  I ordered my parts from Digikey searched individually then add them to your cart.  Of course you may select any other distributor of your choice, including off shore sources.

Hi, I have made similar boards to these and put in many of my coaches, this looks cleaner than what I have done. My question, when ordering the PCB, you mentioned ordering in sets of three, is that automatically done, say one order @ $3.80 / 3 PCBs? I want to make sure I don't end up with 3 times what I need.

I have never ordered these before, hope I don't sound to stupid.

Ray

@Rayin"S" posted:

Hi, I have made similar boards to these and put in many of my coaches, this looks cleaner than what I have done. My question, when ordering the PCB, you mentioned ordering in sets of three, is that automatically done, say one order @ $3.80 / 3 PCBs? I want to make sure I don't end up with 3 times what I need.

I have never ordered these before, hope I don't sound to stupid.

Ray

When you order boards from OSHPark, they are in quantities of three, that's the way they do business.  It's clear on the website the quantity you are getting.  Right after you drop the ZIP file with the Gerber files in it on the page they calculate the cost and show you this notice.  You can order three, six, nine, etc., they come in groups of three.

Here’s a sample order as an example, GRJ sez choose the 0.8mm thickness for the same money and a thinner board.  As you see, quantity 18 divided by 3 = 6 x $3.80 = $22.80 shipped.  Edit:  There is a narrow version also.  Identical in operation.

@TedW posted:

Here’s a sample order as an example, choose the 2oz copper option for the same money and more current capability.

Actually, given the fact that the whole circuit only handles milliamps, more current capability is a moot point.

That being said, I actually do select the 2oz copper option, but for a different reason.  It's also .8mm thick instead of 1.6mm thick!  The thickness is why I pick it, no need to have the board any bulkier than necessary.

Explanation fixed as noted...

If you don't mind waiting longer, there are a number of Far East PCB places that will do boards very cheaply in quantity, but it usually takes three to four weeks to get them.

Yup, @Rod Stewart has a link to one of them.  I got a few from him to play around with.  He liked that the holes were pre-tinned.  They are thicker though if that matters.

I order the .8mm boards from the off-shore places, it's not an issue to get them in the thinner material.

A question about the 470uF capacitor recommended in GRJ's circuit.

I have been greatly helped by contributors to this thread and thank them for my being able to convert 8 passenger cars to LED's. So far each PCB I have built has worked well. There is some minor flicker at very slow speeds over some of my older switches, but vastly better than the old incandescent bulbs.

I just acquired 2 new passenger cars (Lionel 1927620) that are already equipped with flicker-free LED lighting. I have noted that on track power-up, these cars take several seconds to reach full brightness and on power-off, they decay very slowly, perhaps over 3 full seconds. Is that due to a different capacitor or some other function?

I still have 7 more Polar Express cars to convert and if I can do a simple upgrade on the capacitor, I would do that to get the longer decay time. Of course, it would have to be the same pin spacing to fit GRJ's board and not be too much bigger.

Thanks for all the expertise freely shared on this Forum!

Bob

The amount of storage and the current setting directly affect the hold-up time for the lighting.  The dimmer you run them, the longer they'll last during power interruptions.

Here's a 1,000uf cap that  will drop in and double the capacitance.  It is taller than the 470uf cap, but the same lead spacing and diameter.

Rubycon 35PK1000MEFCT810X20

@gunrunnerjohn posted:

The dimmer you run them, the longer they'll last during power interruptions.

Here's a 1,000uf cap that  will drop in and double the capacitance.  

Thanks GRJ. Now I understand why some of my car lights decay more slowly than others - these are the ones that have a dimmer setting.

I will try the 1000uf cap - thanks for the link.

Bob