New MTH CP Christmas Stage Boxcar Up in Smoke

Tons of suitable replacements for the blazing regulator module in this car.  The Chinese sell a ton of AC<->DC switching power modules that would do the job with no sweat.

LM2596HV AC/DC to DC Buck Step Down Converter Module 3v 3.3V 5V 6V 9V 12V 15V 24V DC 5V-50V Adjustable Step-Down 3A Power Supply, $1.38 + .95 shipping.  Buy several and have spares.

@gunrunnerjohn posted:

Tons of suitable replacements for the blazing regulator module in this car.  The Chinese sell a ton of AC<->DC switching power modules that would do the job with no sweat.

LM2596HV AC/DC to DC Buck Step Down Converter Module 3v 3.3V 5V 6V 9V 12V 15V 24V DC 5V-50V Adjustable Step-Down 3A Power Supply, $1.38 + .95 shipping.  Buy several and have spares.

I like these even better when the shipping was free !!  I wonder how that works ?  Who pays the USPS to deliver it once it hits the USA ?   I have a stock pile of the various Chinese modules I have in use all over my layout.  I just installed a variable AC to DC converter as a speed trimmer for my back and forth Ice Delivery car.

If I use one of these converters in the Stage  boxcar I need a series dropping resistor for the LEDs.  How do I size the resistor since I don't know the LEDs forward voltage or current ratings ?  There is also the question of how the LED's are wired.  Parallel makes sense but the LED bundle has 3 wires ?

Also, the MTH replacement part has NO dropping resistor.   The resistor has been jumpered out.  Doesn't make sense as a replacement part if it's not a direct drop-in.

Well, without knowing how the LED's are wired, and how many of them there are, I couldn't begin to size a current limiting resistor.

@shorling posted:

I was investigating the A0000016 board.  Is this the 6v light kit for the dummy A-units you mention ?

A0000016 is offered on the MTH site as a substitute for similar boards no longer available including the Stage Boxcar.    The resistor is omitted and replaced by a jumper on this board.

Do your 100 ohm resistor. and cut the trace modifications apply to the A0000016?   What trace do I need to cut ?   What jumpers do I need to remove ?

The problem appears to only affect the stage cars, the boxcars and passenger cars don't seem to have this problem.  As for reliability...as long as you don't mangle the LEDs you should be OK.  But, the factory in their infinite wisdom, used metal clips to secure the strings which have a thin lacquer coating that can wear through (in my opinion) from handling, vibration, etc.  They switched to fishing line which is what I use when replacing a string.

The AG-0000016 board is the PCB used in the dummy A-unit kits.  There are two jumpers on the board that must be removed, cut the trace between the solder pads that accept the 100 ohm resistor and bridge two solder pads so both LED outputs receive power.  Use the old board as a guide and be sure you have 100 ohms between the voltage regulator output and the LED sockets.

Looks like we just got the CV boards in for the stage car that have the correct resistor and jumper.  Part number is AG-0000116.

@Jon G posted:

Looks like we just got the CV boards in for the stage car that have the correct resistor and jumper.  Part number is AG-0000116.

Jon - Thanks !!    I just want to let you know how much I appreciate the directness, accuracy and follow up of your statements.  Also, the timeliness of your responses !!

Thanks again for letting me know that your new arrivals include the 100 ohms resistor.  I hope those I have on-order which are arriving Monday will be the same. 

@Jon G posted:

These boards have a problem where the solder pads on the voltage regulator are too close together and short.  Usually the LEDs are OK (I just repaired two in the last week); test them with a 9v battery and 220 ohm resistor.  Direct replacement boards are not available, but we use the 6v lighting kit for dummy A-Units, remove the jumpers, cut a trace and move the resistor over from the bad board. Part number AG-0000016.  You must have about 100 ohms between the volt reg output and the connector for the LEDs, or you didn't cut the trace on the board and will burn up the LEDs.

Jon - You were mentioning in this post about repairing/replacing the LED strings.  Do you have the P/N for the strings.  I don't know if there are different length strings or is there one length stocked and we cut to length ?   I have the RailKing boxcars, gondolas and the Stage boxcar.  I tried a year ago or so to purchase spares but they were not available yet.

Thanks 1!

A Question for Gunrunner John:

Could these Buck modules be used to turn my signal system 12VAC input into DC input to feed the various circuit boards in my signal system? I was told that my signals should be powered by DC, rather than AC.

Thanks for your input, although slightly off this topic.

Sure, that's what the board is for, turning AC in to DC.

@shorling posted:

Jon - You were mentioning in this post about repairing/replacing the LED strings.  Do you have the P/N for the strings.  I don't know if there are different length strings or is there one length stocked and we cut to length ?   I have the RailKing boxcars, gondolas and the Stage boxcar.  I tried a year ago or so to purchase spares but they were not available yet.

Thanks 1!

We have replacement strings for most locos and I believe a few boxcars.  For the shorter strings, like on Railking boxcars, passenger cars and flatcars I just use and old string that was removed from a previous repair (usually, part of it is good) or cut a longer string into smaller segments and do the repair.  It's a very laborious process, some taking hours.  We have part numbers for some strings, others are just bagged for our use.  I'll have to look on Monday.

My subject Christmas Stage car looks like it went up in smoke again.  I installed a new MTH power supply (AG-0000116.) early this year and the boxcar has been working fine for 6 months.  As I raised the ZW power the other day the stage LEDs went dark and a few sections later the whole Canadian Pacific Holiday Train when dark.  My fuse protecting the TIU blew I presume.  I have yet to investigate.  Any news on the root cause of this problem and work arounds ?

Are there any updates to this issue?  Just purchased the CP Holiday engine(20-21161-1) and cars (20-92237B) in September which were brand new, never opened.  I ran the train yesterday for the first time for about 10 minutes at a low speed.  Increased the speed a bit on the MTH-1000 transformer and then had one of the box cars "short out" and start smoking.  I have contacted MTH.  Back into the hobby after retiring this past July...quite deflated.  Wish I would have found this forum sooner.  Any fixes?