Walthers Budd car lighting kit

[dipeedo]

I found several lighting kits for the old-fashioned Walthers Budd cars.  But there's mention of "DC" kits and then "DCC" kits. Since I'm runnning EZ DCC command I would think I want the "DCC" kit but I've already bought the "DC" kits and put one in a car and it works, so what am I looking at here ?  I mean, what's the real difference ? None of them are still listed as "in stock", all are obsolete merchandise, so can I make them work?
These are actually for my wife (she's the passenger guru - I do the freight trains and we work together) and are for Christmas presents but I'm having prob understanding.

[jonathan]

I discovered this the hard way:

DC lighting kits will work on DCC... for a short while.  Eventually, they will get too hot, from the extra voltage, and will burn out.  This is a guarantee.

DC lighting is meant to handle a maximum of 12 volts dc. Not good on a DCC layout where the voltage is around 15 volts AC.

Forewarned is forearmed.

Regards,

Jonathan

[sd24b]

I found several lighting kits for the old-fashioned Walthers Budd cars.  But there's mention of "DC" kits and then "DCC" kits. Since I'm runnning EZ DCC command I would think I want the "DCC" kit but I've already bought the "DC" kits and put one in a car and it works, so what am I looking at here ?  I mean, what's the real difference ? None of them are still listed as "in stock", all are obsolete merchandise, so can I make them work?
These are actually for my wife (she's the passenger guru - I do the freight trains and we work together) and are for Christmas presents but I'm having prob understanding.

jonathan is right.  I too found out the hard way.   NFL also mean Not For Long.   phil

[digitalgriffin]

That's good to know about the bulbs burning out on 14.25 VDCC.

That can be easily corrected using a $1.00 voltage regulator, or a cheapo resistor.

I may be mistaken, but the bulbs are actually 1.5 V bulbs bridged across two diodes.  That way they can still work at low track voltages.  This is why the DC light kids cost more because there are more electronics across them.

I have a couple in my basement because walthers stopped making the DCC versions.  I'll examine them and see if I can rig up a circuit and post the photos here.

[digitalgriffin]

Okay I just looked at mine.

The problem isn't the bulbs.  The voltage is first rectified to turn it to DC, then it is fed into a voltage regulator.  The voltage regulator likely puts out 1.2 or 3.3 Volts DC (The black chip with 3 silver legs).  The bulbs them run off the that.  The problem with voltage regulators is they get very hot  when there is a large voltage difference between the input voltage ~13VDC and output 1.2VDC.  All that energy (around 12 Volts) has to go somewhere-namely heat.  Hence why there is metal hanging off it to act as a heat sink.

10:1 there's the voltage regulator chip burnt out.  Put a volt meter across pins 1 and 2 (+ and ground) it should read about 13VDC.  Next put a volt meter across pins 2, and 3, it should read 1.2 or 3.3 VDC.  If it doesn't, then you burnt out the chip.  You can get more here:

http://www.jameco.com/webapp/wcs/stores/servlet/StoreCatalogDrillDownView?langId=-1&storeId=10001&catalogId=10001&freeText=voltage%20regulator&search_type=jamecoall

When you hook them up, you might want to try to add some more aluminum heat sink to them to carry away the heat.  I would use a conductive heat sink glue to hold them in place. 

http://www.newegg.com/Product/Product.aspx?Item=N82E16835100013

I use this stuff for my heat sinks as well as to keep my micro tsunami 750 cool.  IT works great.

[dipeedo]

Well, technically, DCC is "pulsed DC" not AC..  It is the pulseing that communicates commands to the DCC devices.  But all your information here  is very usefull in understanding how the lights work.  (or don't work, or only work for a while.)  That's what I wanted/needed, Thank you.

Usually, there is  no use for a bridge rectifier in a DC circuit, as the purpose of a rectifier is to create DC out of AC. So why is there a rectifier in the cars ?  Is it to supply DC to circuits that are polarity sensitive?

[dipeedo]

modify the last to read:
Is it to supply DC to polarity sensitive circuits when the incoming DC might have polarity reversed, as in a model railroad DC world?

[digitalgriffin]

modify the last to read:
Is it to supply DC to polarity sensitive circuits when the incoming DC might have polarity reversed, as in a model railroad DC world?

There are 4 diodes (black cylinders with silver stripes) that connect to the power pickup points (tabs)  This is a full rectifier bridge which turns bi directional DCC current to regular DC.  This is needed because the voltage regulator chip only works on positive voltage, so it has to be rectified first.  This is a bit more complex a circuit then a simple diode/resistor/capacitor circuit, but it should allow for a wider range of voltage operation.

I assume you have a volt meter?  They can be had for as little as $10, but I got a really good digital one at sears for $25.  It measures resistence, capacitence, and conductivity.  They are very handy tools to have around.

IF it were me, (and it may well be because I use DCC) I would use a 12 V regulator as a replacement, and hook up some wide angle lens white LEDs in place of the light bulbs (with appropriate 150 Ohm resister going from voltage regulator)  The capacitors are rated to 25V, so you shouldn't have a problem there.  Now that's some REAL flicker free lighting better then anything walthers offered.