I am about to convert two Proto 2000 E6A locomotives to DCC.
I plan to install a TCS T1 non-sound decoder with an E6 harness in each locomotive. The TCS website has an illustrated step-by-step process for this installation, making it pretty easy to accomplish.
There is no mention of the Mars light or headlight replacement from which you can infer that these two incandescent lamps are suitable for use with the TCS T1 decoder. This would be fine with me since I have no burning desire to remove and replace the incandescent lamps with LEDs.
But, here is my concern. As usual with Proto 2000 incandescent bulbs, the manual included with the E6A locomotive makes no mention of voltage or current capacity of either the Mars light or the headight. This just drives me nuts.
The specs for the TCS T1 state that the Function Rating of the lighting tabs is 100mA and that the Function Outputs are 12V. So, my fear is burning up the incandescent bulbs on the first power up.
How do you determine the voltage of the two incandescent bubs? Do you just test voltage with batteries or variable voltage DC supplies? Can current be measured with a multimeter?
In researching this issue on the Internet, no one seems to know for sure. Someone says the bulbs are 1.5 volts. Another says it is 3.0 volts. I have even seen mention of 12 volts. Everyone seems to be guessing.
By the way, on the Proto 2000 E6A, the Mars light is a 3-wire incandescent bulb, and the headlight is a 2-wire incandescent bulb.
I would sure appreciate some help from anyone who knows the bulb specs for sure. I really don’t want to burn out these bulbs if I can avoid doing so.
I have a pair of Life Like replacement bulbs new in the package, never used. The single filament bulb is 1½ volts at 40ma. the dual filament are both 6 volts at 40ma.
I have to go back and find the Digitrax link I posted on a similar thread, not long ago. I remember you participated.
The diagram showed which wire needed to be “moved” on the plug. I think it was the yellow wire, as your using the reverse light option of the decoder to run the mars.
I haven’t run this loco in a while, I forget what function key turns the mars of and on.
I did this on my E6, and the mars light works fine. I have no idea what the voltage or wattage is of the bulb.
Well, that is certainly a definitive answer. I am curious, Mel, are those specs listed on the package or did you measure the voltage and current?
Yes, those are exactly the two incandescent bulbs that are factory installed on the Proto 2000 E6A (blue box model).
All of which raises the question once again in my mind. If the Function Rating on the TCS T1 decoder is 100 mA, and the Function Outputs are 12V, what’s to stop both incandescent bulbs from burning out as soon as I power up?
So, you left the factory installed incandescent bulbs in place? No resistors?
So, you’re saying to just leave the factory installed incandescent bulbs in place, which is what can be inferred from the TCS installation which is silent on this issue?
If this is so, I am confused as to what prevents these lower wattage bulbs from burning out when connected to 12V function outputs.
I powered them up this morning using my Fluke meter for current. I was a bit surprised at the voltage difference between the bulbs.
I also used a AA battery on the headlight just for kicks and it looked perfect. I checked the dual filament bulb in series and sure enough both filaments were equal brightness, 12 volts at 40ma.
By the way the bulbs have a color coded base, the 1½ volt is white and the dual filament is red.
The Mars light doesn’t get connected to a decoder function when you plug a decoder in the 8 pin socket. That jumper to the normally unused pin on the 8 pin plug is so that the function output can feed the Mars flasher circuit on the factory board.
I never understood why they made the harness so long, the decoder can easily fit at the rear of the frame - actually, a T1 even fits ABOVE the factory board, which is where I put it int he one I did - but I hardwired mine in. I left the factory board and didn’t cut the factory wires short so they could be clipped back to the factory board.
Not sure why you are so against swapping in an LED, there’s tons fo room to run the wire, it’s not close quarters. And the Mars light effect from the decoder is far superior to the blink back and forth of the two filaments using the factory board. This one’s pretty easy since there is a lot of room in there, and LL used the right colors for their wires, except the motor wires, but the M= and M- are clearly marked on the factory board - and it’s not some out there color scheme, red motor wire goes to decoder orange, and black motor wire to decoder grey.
Yeah, I don’t understand why Life Like chose to use two different voltages.
I keep notes on my DCC conversions. I have a note that states that the Mars light is 12V and the headlight is 1.5V. I assume that I used different sized batteries to test the voltages.
I always accuse myself as being “electronically illiterate”. I can do household electrical projects with no problem, but when it comes to model railroading and electronics, my grasp is less than desired. So, with that in my mind, let me ask this question.
You mentioned that the the dual filaments on the Mars lamp are both 6 volts at 40ma. But, you also mentioned that the dual filament bulb in series is 12 volts at 40ma. I assume that is no typo, so does that mean that the dual filaments of 6 volts each total 12 volts?
I would like to try what Randy suggest, with the LED, but I don’t think the 2 function decoder that I used (DH126) with the harness, can be programed to do that.
OK, maybe that explains my confusion. The TCS website illustrates the solder bridge connecting the yellow and green wires on the 8-pin board to accommodate control of the Mars light. Does this arrangement somehow explain Mel’s readouts of two 6V filaments in series to produce a 12V bulb?
LOL. I have no idea either why the decoder is so far away from the light board. You need to spend another $10 to buy a wiring harness to reach the board from the decoder.
I would like to install LEDs in place of the Mars light and the headlight, and I may well wind up doing just that.
But, my reason for hesitation is the way that the two bulbs are mounted. They fit into a clear plastic holder which is not all that well secured. If I tamper with the bulbs and that plastic piece comes loose, it is difficult to maintain the proper position of the bulbs.
On a pair of Proto 2000 PA locomotives that I converted to DCC, that happened and I had to play around with the two lights for quite awhile to get both to show light through the housings. There isn’
You don’t need two LEDs - the decoder can flash a single LED just fine.
The two function Digitrax decoder can’t drive a replacement LED Mars light, but it CAN drive the factory one - you need the same sort of jumper on the 8 pin plug as the TCS one (you can even buy the TCS harness seperately and use it on the Digitrax decoder, the 9 pin end at the decoder is exactly the same. I’m not sure the 2 function TCS T1 can do the headlight plus generate a Mars light effect on the other function which is normally the rear light either. Possibly - the TCS function mapping is a bit more flexible than Digitrax’s, at least on the decoders with limited function outputs.
It’s not because the factory incandescent Mars light has two 6 volt filaments that makes it work - it’s because it is driven by a special circuit on the factory board. If you look at that board, you’ll see that it’s not your typical P2K board with a few diodes. There are a couple of transistors, resistors, and capacitors. They form some sort of oscillator circuit that alternately powers the two filaments. The deisng of this circuit is what keeps the voltage in check - remember it does work on DC, the bulbs don’t burn out at full speed on DC, which is at least 12 volts feeding the circuit.
This discussion makes me wonder about whether you need to leave the factory board in place to at least keep the 1.5 volt headlight from burning out.
Does the factory board circuitry protect the low voltage headlight? That would explain how the TCS installation of the T1 decoder is accomplished without replacing the factory installed incandesc
You don’t need two LEDs - the decoder can flash a single LED just fine.
The two function Digitrax decoder can’t drive a replacement LED Mars light, but it CAN drive the factory one - you need the same sort of jumper on the 8 pin plug as the TCS one (you can even buy the TCS harness seperately and use it on the Digitrax decoder, the 9 pin end at the decoder is exactly the same. I’m not sure the 2 function TCS T1 can do the headlight plus generate a Mars light effect on the other function which is normally the rear light either. Possibly - the TCS function mapping is a bit more flexible than Digitrax’s, at least on the decoders with limited function outputs.
It’s not because the factory incandescent Mars light has two 6 volt filaments that makes it work - it’s because it is driven by a special circuit on the factory board. If you look at that board, you’ll see that it’s not your typical P2K board with a few diodes. There are a couple of transistors, resistors, and capacitors. They form some sort of oscillator circuit that alternately powers the two filaments. The deisng of this circuit is what keeps the voltage in check - remember it does work on DC, the bulbs don’t burn out at full speed on DC, which is at least 12 volts feeding the circuit.
richhotrain
All of which raises the question once again in my mind. If the Function Rating on the TCS T1 decoder is 100 mA, and the Function Outputs are 12V, what’s to stop both incandescent bulbs from burning out as soon as I power up?
Well if you repalce the Mars light with an LED - might as well replace the regular headlight with an LED too. Both with a 1K resistor, and you don’t need the factory board. There’s plenty of room in those locos, so you don’t actually have to remove the factory board. Just pop the palstic caps off to release the wires and connect like colors to like colors (exception being the motor + and - which are red and black in the loco but are the orange and grey from the decoder) and you are set. For the repalcement LED lights, there’s a blue wire to the main headlight, this is the + common, so connect the + side of both the headlight and Mars light LEDs to this wire. The white wire is the headlight - (you can put the resistor backat the decoder instead of trying to cram it in by the LED - use the resistor to connect the decoder’s white wire to the loco white wire). One of the other two wires to the Mars light is yellow, hook the - side of the Mars light LED to that one. Back at the decoder, do the same with the yellow - use the resistor to connect the decoder yellow to the loco yellow.
Obviously shrink tube on all the connections so nothign shorts, but there is plenty of room for a decoder as large as the T1 on top of the factory board without preventing the shell from fitting. If you want to use the KAT1 with the keep alive built in, might have to take out the scres and remove the factory board. But a big, heavy, long wheelbase loco like that shouldn’t need a keep alive.
I used some deductive reasoning to answer my own question, i.e., how come the 12v function output on the decoder doesn’t burn out the Proto 1.5v headlight lamp immediately upon power up? The answer is, the 12v function output on the decoder does burn out the Proto 1.5v headlight lamp immediately upon power up.
On the Proto 2000 E6A, with the factory board left in place, the 12v function output on the decoder is filtered through the light board to limit the voltage reaching the 1.5v headlight lamp. No burned up headlight on power up.
This explains how I burned up the 1.5v headlight lamp on one of my Proto PA locomotives. When I initially converted both PAs from DC to DCC, I left the factory installed light boards in place, and the 1.5v bulbs never burned up. However, when I took one of the PAs apart to resolve a tracking problem and then rewired it, I pulled out the factory installed lighting board and hard wired the decoder back in place. The 1.5v headlight lamp instantly burned up.
