Hello,
The lights in one of my modern era Madison cars stopped working. I tested the bulbs and they work. All connectors show continuity. I called Lionel and they are not taking part (regulator board) orders until late August.
It's really not much of a circuit board, so, I decided to fix it myself. There are three electriacal components on the board. I found the capacitor and the +12v regulator but I am hoping someone can tell me what type/value is the diode on the board. It reads 100t. I can't locate it.
Any help would be appreciated.
Thanks,
Brian

This message has been edited. Last edited by: brilite,

I have had wiring problems with a few of these cars. Look over the wiring closely where it solders to the ground contact that rides on the axles. Also the wire to the roller contacts can let go where it solders to the assembly. Modern Lionel is using stiffer thinner wire that doesn't easily flop aside when it breaks off a solder point. So a lot of times it looks connected when it isn't.

I have not seen the board. A simple regulating circuit would be a 1n4001 diode,(1 amp,50 volt provides half wave rectification),a 7812 regulator and a capacitor usually 220 uf or 470 uf 35 volts. Not likely the board is bad but rather a continuity problem somewhere. Looking at the face of the regulator with the pins wired 1,2,3 from left to right. Voltage between 1 and 2 should be track power times 1.4 volts DC.

Voltage before the diode should read track voltage AC.

Voltage between pins 2 and 3 should read 12 VDC if track voltage is 14 VAC or more.

To test turn the car over and hook up 2 alligator clips from a transformer to the pickup roller and wiper blades (or car frame). Test leads described for voltage.

Dale H

Thanks bigo426, the wiring tested ok. I bypassed the regulator board and wired other lamps which worked.

Thanks Dale, the capacitor is 220uf 35 volts, and the regulator IS 7812. I'll get the diode you recommended and give it a try.

Brian

Brian

Make sure you install the diode in proper polarity. Backwards the capacitor will explode and regulator will burn out. the + of the diode should go to pin 1 of the regulator.

Dale H

Dale,
Thanks, I bougt the diode yesterday. I will begin work when the cap and reg. arrive. I will replace each component one at a time and test. Can you suggest which component to start with, or does it matter?
Brian

Brian

If I had all the parts ,I would replace all 3 at once. if the diode failed,it could have ruined the regulator and cap.

Dale H

And Brian, could you video tape the repair please? I want to see the look on your face if the cap blows! I can remember the first one that I blew. A very loud bang and it scared the hell out of me!

Bob H.

Dale,
Will do, thanks.

Bob,
I'll ask my wife to record the procedure (from 20' away) and I'll be sure to wear my shooting eyes and ears.
Brian

Dale,
I replaced the three components on the regulator board and fixed the problem. The lights light and the regulator does what it is supposed to do. It was a straight forward procedure.
Thank you for your expert advice and guidance.

Bob,
Nothing exploded and there were no fireworks!

Thanks again to all.
Brian

Brian

Glad it worked,thank you for the kind words,it is much appreciated.

Dale H

It is always cool when we can fix a problem and get the engine or car back on the line where it belongs. I think of it as one of the highlights of our hobby to do my own repairs when I can. Dale nice helpful tips. This kind of help makes this a great WeB Site for our trains...

If anyone else here experiences what they think is a bad diode try this. Heat the solder joint at one end and lift the end of diode out of the board there.
Then check with an ohm meter.If it checks short or very low ohms both directions
(swapping leads)its bad.Same if it checks very high to infinity both ways.
Sometimes it can be difficult to Identify components as companies will put coded numbers on them to protect their stuff from reverse engineering theft and unauthorized repair.
Rob

Brian

Just one last word on this. These board usually do not have problems but like anything can fail.. If the one you rebuilt fails again check for some kind of intermittent short or bare wire to frame type problem.

Dale H