I've seen a number of melted things with the incandescent bulbs.  My fix is to swap out the bulbs for an LED with a 270 ohm resistor in series.  It drops the power dissipation to a fraction of the bulb's heat and totally solves this problem.  Not only that, but the LED's look much better as headlights.  I get a lot of units in with a request to upgrade to LED lighting, and nothing is melted on those.

gunrunnerjohn posted:

I've seen a number of melted things with the incandescent bulbs.  My fix is to swap out the bulbs for an LED with a 270 ohm resistor in series.  It drops the power dissipation to a fraction of the bulb's heat and totally solves this problem.  Not only that, but the LED's look much better as headlights.  I get a lot of units in with a request to upgrade to LED lighting, and nothing is melted on those.

Thanks John. Odd occurrence, never had anything like this happen before let alone two engines in a short time. 

Not with trains, but I have had cartons of the small wedge bulbs labeled wrong on the bulbs (should have been 12v, but were 6). Maybe they got a bad batch too.

I've heard about the really bright headlight before over the years..... If  I remember correctly the cause may have been a faulty MUX board...

I'll try and get l.e.d. headlights from MTH and then do some body work again. Glad its' black paint and easy to match.

I remember the ps2 aero train had the same issues with the Obs car.

PAUL ROMANO posted:

I'll try and get l.e.d. headlights from MTH and then do some body work again. Glad its' black paint and easy to match.

You can't get the replacements from MTH, they don't do LED's for PS/2 stuff.  However, it's easy to "roll your own".  I typically use the existing headlight wiring and just cut one leg for the resistor and solder the 3mm LED on the ends of the wire in place of the bulb.

Most of the MTH passenger cars have a strip of aluminum tape stuck to the ceiling above the bulbs to reflect the heat . Strange the same is not done on the diesels. Looks like I'll be removing some shells and adding some. I really like the golden color of the incandescent headlight. Wish there was an LED that could match it. The cool blue white color of an LED  headlight just doesn't look right to me. John, do you have an outlet for an LED that looks better?

Dave, there IS an LED that matches the color of incandescent bulbs.   I have them in stock.  They're 2700K color temperature, and they look GREAT, not to mention they're far brighter than the incandescent bulb, they look like real headlights and in the correct color.  I get the flangeless LED's to replace the bulbs, they're the same diameter and no flange, so they fit where the bulbs do.

I wonder if you could install a small heat shield as temporary fix?

Thanks John, can you bring some to York along with resistors. I could use about 10.

Dave, send me an email and we'll make an arrangement.

A while ago, I did a post on making an LED headlight.  The resistor value was worked out with Jason at MTH.  FWIW, none of the LED headlights I have made have failed.

85 REPLIES

LED Headlight replacement for MTH locomotives.

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MARTY FITZHENRYMEMBER DIGITAL SUBSCRIBER

4/18/156:43 PM

 

 

Over the past years I have done many DCS upgrades.  Several people wanted bright white LEDs in headlights and backup lights.  My good friend Locolawyer is the guy I blame the most for this request.  Recently I have had members ask me to throw something on the forum instructing how it is done.  Very simple and very cheap to do.  On PS2 and PS32 boards the wires for the front headlight are light blue and purple.  Light blue coming from the number 5 pin on the 12 pin connector and the purple comes from the 2 pin on the 12 pin connector.  The rear lighting is a light green wire from pin 4 on the 12 pin connector and the purple from pin 2 on the 12 pin connector.  On front and back lighting, follow the purple wire to where your lights plug in.  The purple  is the hot wire and the corresponding wire that you need to put your resistor in on the light side of the plug.  Cut the wire and insert a 560 OHM 1/2 or 1/4 watt resistor.  Next cut the bulb off the wires and connect the longest lead from the LED to the other end of the resistor.  The long lead is plus.  Connect the other wire (negative) to the ground side and you now have LED headlight/backup lights.  I will outline this a bit better with a few pictures.

 

 

The photo above shows left to right a section of 3/64 heat shrink, a section of 3/32 heat shrink, next a 3mm bright white LED.  This is Lionel p/n 6102045300, and a 560 OHM 1/2 watt resistor.

 

 

 

Above is the resistor I used.  You can buy what you need at many locations and they are very inexpensive.  No polarity is needed.

 

 

 

 

Above is a front MTH conversion showing the light blue and purple wires used in the front headlight.  This is the original incandescent light from the upgrade kit.

 

 

 

This shows the finished product without the shrink to show you the path of the purple wire to the resistor then to the LED.

 

 

 

 

 

 

This photo shows the final product with heat shrink installed.

 

 

 

 

This shows before and after.  You are out about 20 minutes of your time and about two bucks.  If you like the LED look, anyone can do it with no special skills.  The LED I used was from Lionel and the resistor from a local parts store.  You can use any manufacturer of the products.  I did some testing with these a long time ago with MTH R&D and the correct resistor we came up with was a 510 OHM.  You can go down to that if they are available to you.

 

 

 

This is an MTH PS1 upgraded Hudson for Locolawyer.

 

 

 

The rear of the Locolawyer Hudson.

 

 

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Thanks Paul for the warning and thanks Marty for the instructions. Email sent John.

Marty, I'm not sure where they came up with the value of 560 for the resistor.  Obviously, you'll get plenty of light with that value, but the PWM drive to the bulb results in an effective voltage of about 6 volts.  Most common LED's have a peak forward current of 100ma or more, the roughly 20-22 volts on the PV that is PW modulated results in a peak current through the LED of less than 90ma using a 220 ohm resistor, well within the ratings of the LED.  I typically use a 270 ohm resistor for a little larger margin of error, the peak current ends up being less than 75ma, and the average current is around 14-15ma.

Can you turn the light on and off with DCS?  If not, the light control FET has shorted and your getting full DC voltage to the bulb.  That is what usually happens and than melts the shell and the bulb ultimately blows.  So check to ensure the FET is working first.  I have not really seen properly operating bulbs melt shells.   G

GGG posted:

Can you turn the light on and off with DCS?  If not, the light control FET has shorted and your getting full DC voltage to the bulb.  That is what usually happens and than melts the shell and the bulb ultimately blows.  So check to ensure the FET is working first.  I have not really seen properly operating bulbs melt shells.   G

Thank you. I'll have to check that. The engine is at the NJ Hirailers club.

John, yes the 220 will work.   So will many others.   With Jason, time was spent to come up with that value I posted.  Bottom line, we have been doing this for years with not ONE issue.   

GGG posted:

Can you turn the light on and off with DCS?  If not, the light control FET has shorted and your getting full DC voltage to the bulb.  That is what usually happens and than melts the shell and the bulb ultimately blows.  So check to ensure the FET is working first.  I have not really seen properly operating bulbs melt shells.   G

Thanks GGG. I thought it was the MUX board but obviously that's  not the case .    FET make more sense and I would think one  would want to get at the bottom of the problem  first.