Headlight flickering when smoke unit is turned on.

Check out this post.

https://ogrforum.com/d...ent/3963862654343860

Mort

Noticed this at the club some time ago. Don't remember if there was a fix. Easiest way to correct the problem is to turn the smoke unit off.

Al

Thanks Mort,

   It sounds like the easiest fix is the swapping of the blue wires on the MUX board. I only wish they would have went into better detail. Is this board in the tender?

Check this post, there is a photo of it.

https://ogrforum.com/d...435#2415514336734435

Mort

I have a MTH engine & I think it is a H12or H10 that had the same problem & MTH fixed it even though it was out of warranty. It was a design problem. Call MTH & explain & I believe they will repair at N/C. Mine was probably 5 or 6 years old then.

I've come to the conclusion that I have three choices. Send it to MTH, change over to LED and use track voltage, or don't use the smoke unit (which takes alot of the realism away). If I changed to LED, I would have to build 3 circuits, headlight and two marker lights. I would also lose control of the headlight and it would no longer be constant voltage. Thanks everyone for your help. I was hoping it was going to be a simple fix. I hate sending these trains back for repairs, because I've had one come back damaged one time, but it looks like my only choice. 

If you have a MTH tech in the area he could do the mod, but he may charge you.  MTH is the best route to go, just ensure you pack it well.

Also, most likely the battery is dead, and this engine may also have the 16 ohm speaker that deteriorates.  So you may want to inspect it and run it well for sound quality.  G

Had same flickering marker light/cab light problem with 2008 PS2 cab forward when smoke unit was on. MTH replaced the MUX board, but the problem persisted. Had several emails with an MTH tech, and he advised limiting the input voltage from the ZW to the TIU to 17 vac. This solved the flickering light situation.  Phil

There are a lot of ways to run off track voltage. If you run only command,all you would need is one small bridge rectifier and 3 resistors. The markers could be wired in series then, only 2 resistors needed. I assume these are already LEDs. For conventional-command you still only need one bridge rectifier a small capacitor,a choke and 2, cl2-n3 chips. Really only one circuit driving 3 LEDs.

Also,never tired it you might try a capacitor 100uf or 220 uf 35 volt in proper polarity on the existing output and convert the headlamp to an LED with a series resistor. This might remove the flicker.

I have the MTH service manual,the fix described is a bit complicated as I remember. Involved changing wires and adding a resistor. However if MTH service will fix it free it might be the best course,assuming you get it back in one piece.

Dale H

This would require replacing or modifying both MUX boards (Tender and Engine) plus adding a thick ground wire to the Engine MUX board.  G

Dale, I think the bulbs are standard, not LED. This engine is from 2001.Thanks GGG, but I am running with bricks at a fixed 19 to 20 volts. I wonder if Dale H would know why over voltage would cause the flickering. I do notice that the flickering does not start until power is sent to the drive motor and the train starts moving, but no fluctuation when the train runs with the smoke unit off. So it is a combination of the two motors running together. Is the drive motor recieving AC or DC current from the circuit board to run?If it is running off AC, is it possible that some AC sign wave is bleeding over into the DC smoke unit circuitry and causing the voltage to fluctuate? Would there be a way to filter the voltage to the bulbs using a small rechargable battery that would absorb the over voltage spikes and take up the slack in the voltage drops?  

The capacitor mentioned might work, but I would get rid of the bulbs and convert to LEDs. I have some PS1 units with green markers and I remember buying replacements from MTH. They were catalogued as 6 volt LEDs. To tell if it is an LED,unplug the marker and hook to a 3 volt battery or DC power source. It should light one way and not the other.

Dale H