Shay Headlight Dim:

[Jon]

I have a brand new Bachmann Shay with the factory installed sound system.  Everything seems to work and the sound is great.

The only problem I have is the headlight is dim and I can't figure out how to get it on bright.  I am using a digitrax dcc system.

I've been through the manual and still can't figure it out. Can you help?  Please make it simple.

Thanks,
Jon

[richG]

My experience with Spectrums so far is the same. Bachmann uses higher value resistors for the lighting.

Rich

[WoundedBear]

I have a few Shays and can't say that any of them have overly "bright" headlamps.

I think it's due to the design of the model....I think the bulb is buried at the bottom of a light pipe, and it's hard to tell if the light is even on unless you're looking directly at it.

Sid

[richG]

It seems Bachmann does intentionally use dim lights for the steamers from what I have read so far. No doubt the same for the Shay.l

The Spectrujm 4-6-0 PC board the decoder is plugged into has  1,770 ohms resistance in series with the plus lead, blue wire,  for the LED. There is a diode in the minus lead, white wire, that drops the voltage by .7 volts. Good reason for dim lights when plugging a decoder into the PC board. If you hard wire a decoder, a 1,000 ohm resistor is sufficient. I have done that with a Spectrum 4-4-0 and a Spectrum 4-6-0.

The Spectrum 4-4-0 PC board has 1,424 ohms in series with the blue lead and a diode in series with the white lead. The LED is a little brighter than the 4-6-0 but when the LED is off, you can see the LED behind the lense.

The 4-6-0 uses a periscope to bring the light out to the headlight lense. I have opened up the 4-6-0 and the LED is kind of dim.
The PC board uses SMT components so replacing the resistor is not an option unless you know how to work with SMT components.

Rich

[Jim Banner]

The DCC Consolidations are the same - a yellow LED and a 1.5k resistor.  Is it supposed to glow like an old oil headlight?  Or did Bachmann receive an order of low efficiency LEDs by mistake?  I don't know.  I just go ahead and replace them with a 3 mm warm white LED and a 1k (1000 ohm) resistor.  This is more in keeping with an incandescent headlight which to me makes more sense for a locomotive sporting a dynamo on top of its boiler.

By the way, Christmas is coming.  If you are tired of paying up to $4 each for warm white LEDs then think about getting a string or two of LED Christmas lights and taking the LEDs out.  That knocks the price down to 30 to 40 cents each now and probably half of that right after Christmas.  The 3 mm style make great headlights while the 5 mm ones with a dimple cast into the end work better for general lighting.  Just make sure you find "warm white" on the box or you will likely end up with the blue-white ones. 

[richG]

My 4-4-0 and 4-6-0 have more than 1k resistance and a diode in series also. I measure 4.1 ma LED current with the 4-6-0 PC board.
A 1k resistor and LED, I measure 9.5ma. I can see a difference in the light intensity also.
I then use a potentiometer to use as a resistor with 12 vdc. I adjusted the pot until I read 4.1ma like the Spectrum PC board gives me. I then measure the resistance of the pot and I see 2230 ohms. With both loco PC boards I traced out the resistor ans diode in the path of the LED current. A diode offers about 600 ohms resistance. With an ohm meter, you can see about 600 ohms resistance when the diode is forward biased. That is why I used a pot to simulate the total resistanceof the PC board. Hope this helps.

Rich

[Jon]

Thanks, guys for the replys.  Now, could you please explain to me in simple terms where to find the resistor I need to change and what to look for.  I am a novice at this sort of stuff and really don't know where to start.
Don't want to screw it up.
Thanks,
Jon

[richG]

Thanks, guys for the replys.  Now, could you please explain to me in simple terms where to find the resistor I need to change and what to look for.  I am a novice at this sort of stuff and really don't know where to start.
Don't want to screw it up.
Thanks,
Jon

The resistors are on the PC board. I have not seen a Shay PC board. Most probably the resistors are SMT devices and difficult to work with as they are so small. If you have electronics experience then it is possible. You would need a multimeter on resistance to trace out the components. I believe you have rear as well as front lights. If you do not have experience at doing this kind of work, you can see if Bachmann will exchange for another loco or just live with it as some people are doing.
I wish I could be of more help.

Rich

[chuff_n_puff]

This might be a silly question, but are you checking the light brightness with it running or sitting still? A lot of engines have a dim idle light but brightens when set in motion.

[Jon]

Chuff,
    They tell me there is no such thing as a silly question.  Actually both.  I have checked it sitting still and with it coming down the track.  It is so dim that you can't tell it is on when it is moving unless it is right in front of you.  In fact at first I thought it was burned out.
Thanks,
Jon

[richG]

I have searched around and find this dim light issue that others have. The only fix I know of is to hard wire the decoder and use a 1k resistor. Some others have tried a different decoder with the same results. The PC board the decoder plugs into is the problem not the loco headlight itself. I think Bachmann did this because different DCC control systems have different power supply voltages, some higher than 12 volts.
You have to be familiar with electronic components to modify the resistor value on the PC board.

Rich

[Joe Satnik]

Build a lamp resistance tester
Model Railroader, February 2002 page 88
Match headlight bulbs and resistors to DCC decoders
( COMMAND, CONTROL, DCC, DIGITAL, "KOSIC, BOB", LAMP, RESISTOR, TESTER, MR )