About a month ago, I upgraded my DCC system from an Atlas to a Lenz 100.
It was a relatively painless conversion since both systems are compatible with my CVP wireless throttle. About a week ago, I noticed that the headlights on most of my locos were not working. My DCC fleet consists of 4 BLI steamers, a Spectrum Consolidation, an Athearn Mikado, and two BLI diesel switchers. The only ones with working headlights are the Mikado and one of the switchers.
The most obvious answer is the bulbs have burned out but I find it odd that so many would burn out at about the same time. Also, it would be strange to have both the front and rear lights burn out at the same time. At no time have I seen one working and not the other. Before I go replacing the bulbs, I wondered if there might be another solution. Some that I have thought of:
Excess voltage to the track. I am using an old MRC power pack with a stated 16v output which is right in the middle of the 14-18 recommended in the Lenz manual. I have heard that the stated voltage is unreliable on some MRC packs and the actual voltage sometimes runs in the 20s. I would think that the decoders themselves would be more likely to fry from excess voltage before the headlights but that is just an uneducated guess.
I have inadvertently set a CV somewhere so that the headlights do not respond when I press the function 0 key. The display on my throttle shows when the headlight setting is on so I know that that function is set correctly but I wonder if there is another CV that might override that setting. I have read both the Lenz and BLI manuals cover to cover and if there is an answer there, I missed it.
Those are just a couple thoughts I have had. I would appreciate any comments anyone might have regarding this problem. I would feel kind of silly if I went out and got replacement bulbs for all these locos and found that the problem was elsewhere.
Can your Lenz system do a recovery program on a decoder? Could be a programming issue. I’ve had it happen in the past with my NCE system, but all I have had to do was reset the decoders to baseline, then redo the addresses, and presto! All is well again.
When you changed from Atlas to Lenz, did you change the power source, or just plug the Lenz in where the Atlas was? If it’s a new source, I’d suspect more voltage than before.
Your Lenz can do a reset for the decoder. After you do that, try running the engine as address 3 (where the reset will put it) and see how the lights work there. There are, by the way, CV’s which control which functions are controlled by which keys, and if those get zeroed out the lights won’t work unless you reprogram them or reset the decoder.
You can also tell if it’s the bulb or something else - when you hit F0 on the BLI steamers you shoudl hear the generator whine as it starts up, and it shoudl trail off when F0 goes off. If you hear these sounds but no light, the bulb is probably blown - although the BLI locos have LEDs. However - excess voltage could result in too much current depending on the resistor value used by BLI. LEDs are probably more sensitive to overcurrent than regular bulbs are to running a couple of volts over rating.
You can do a rough check of track voltage with an ordinary meter as well. First, put it on the AC setting and measure track votlage directly. No, it’s not accurate unless you have a very expensive meter with true RMS capability, but if it’s over 14 volts AC it’s DEFINITELY too high. You can reduce input votlage, and Lenz also has a software setting to reduce track voltage. Using their stock transformer the track voltage is often 18v or higher - WAY too much for HO. With an old MRC power pack as the input - who knows. You should consider a proper transformer as well - the MRC (unless it’s one of the REALLY big ones like the ControlMaster 20) is not going to put out enough current to operate the booster at full capability - the MRC pack will trip on overload before the booster is even half loaded.
The second way to check track voltage is to check DC voltage between one rail and the ground connection on the booster. The two numbers should be close to one another (Lenz can run a DC loco on address 00 - make sure address 00 is set to speed 0 first). Add them together and get a decent representation fo actual track voltage.
More on the LEDs - if they used a 560 ohm resistor sucha s the one supplied with the Miniatronics Yelo-Glo LEDS, under 12V to the track you get about 15ma to the LED. But if the track voltage is actually closer to 18V then the led is running over 25ma, too much for most ‘white’ LEDS. THis is why I use 1K resistors in my installs. That’s 9ma at 12v but still less than 15ma if the trac
Well, I have some good news. The bulbs are not burned out. I wired up a short section of track to an old DC throttle and ran several of the BLI locos and the headlights all worked, including the rear ones when backing up. Now I have to determine what I did inadvertently that programmed the decoders to not respond to the F0 key. I suspect I did something when I was playing with the throttle to mute the sound for engines stored in the roundhouse. Since I am juggling three separate building projects right now I haven’t had the time to sit down and reread the manual to figure out how to reprogram the locos so that the headlights work. It’s always something.
Easiest thing to do is just reset the decoder. Depending on which model, there’s either a jumper on the board in the tender (under the hatch by the volume control) or the magnetic ‘magic wand’. You’ll have to reprogram the address, since the reset will set them back to 3 again, but that beats trying to figure out what obscure CV you may have accidently programmed that disabled F0.
I’d still check the voltage on the track, just to be sure.
Also check your speed step settings.Some decoders will not operate the headlights if the speed steps do not match the command station.If your command station is at 28 speed steps your decoders need to be set at 28 also.You may be in 14 speed step mode.Dan