PRR/Conrail Juniata Division Engineering Report

[Dave V]

Pennsy and 1956 are back on the Juniata Division...   

[eric220]

Much better.

[Dave V]

My latest endeavor has been to work with my Alkem Scale Models PRR position lights, but I was quickly reminded today why I can't have nice things.  5 or 6 years ago my effort was cut short by my immediately toasting an LED on the head.  The center, of course.  Well today, armed with 1000 ohm resistors, I attempted again, this time using Logic Rail Tech signal animators.  I applied power using a DC power pack.  According to Logic Rail Tech, I did not need a resistor on the common, but did need one on the lights.  1000 ohms on the center.  Applied a tiny bit of power.  Nothing.  A little more, a little more, nothing...  then zap!  Toast.  Son of a...

http://alkemscalemodels.net/ASMMain/SignalLights.html

I'm smart enough to know my limits.  Clearly I can't do this.  But now my only OTHER choice are the NJ International signals:

http://www.modeltrainstuff.com/N-J-International-N-2045-PRR-Position-Lite-Signal-p/nji-2045.htm

Cruder than Alkem, yes, but the pictures aren't terrible.  They look a lot better than what I have now.  BUT...  If I can toast Bernie's heads that easily, what's the probability of me eating 50 bucks the first time I plug one of these in?  Holy crap, this is depressing.

To add insult to injury, the Alkem heads are long out of production.

[DKS]

I applied power using a DC power pack.  According to Logic Rail Tech, I did not need a resistor on the common, but did need one on the lights.  1000 ohms on the center.  Applied a tiny bit of power.  Nothing.  A little more, a little more, nothing...  then zap!  Toast.  Son of a...

Was that a "pulse power" pack, by any chance...?

Next time, try a battery pack. 3 or 4 AA cells should do.

[Dave V]

Was that a "pulse power" pack, by any chance...?

Next time, try a battery pack. 3 or 4 AA cells should do.

Indeed it was...

Theoretically I should be able to use the DCC AC current info the signal animator.

[DKS]

Indeed it was...

Theoretically I should be able to use the DCC AC current info the signal animator.

The signal animator likely cleans up the power passed through to the LEDs. So, when testing LEDs, always start conservative. And above all, avoid pulse power of any kind like the plague.

[Dave V]

So miracle of miracles...  LOL...  Using a 1.5V AA battery, I discovered the center LED...  still works...?  Hey, whatever, man.  I'm pumped!

[Dave V]

Turns out the toasted aspect is #6 (permissive block), the one I wasn't planning to use anyway (I intend on using the standard 3; clear, approach, stop).  Dodges a bullet.

Thanks for the heads' up on the pulse power, DKS!

[Dave V]

I plan to contact Logic Rail Tech today just to ensure the signal animators I have will meet the 15V in/5V out specs and ask about the resistor on common.  Bernie's LEDs still need less than 2.5 V.  Dim is okay...  Smoking is not.

[eric220]

No, don't release the magic blue smoke that makes all electronics work.

[davefoxx]

No, don't release the magic blue smoke that makes all electronics work.

Electronics' smoke and Micro-Trains' factory air are two things that you should never let out.   

[Philip H]

Electronics' smoke and Micro-Trains' factory air are two things that you should never let out.   

Not to hijack Dave's thread too much . . . but the week after the Fall Rail B Q I don't think we need to be talking about gaseous releases.  Just sayin . . .

And now back to our regular programming.

[sizemore]

Goto Radio Shack and get a bread board, I find them very useful for both DCC tester as well as wiring circuits (and LEDs). When playing with resistors and LED's I use a 9v battery to the bread board.

The S.

[Dave V]

Seems tall. My PRR Standard Plans book shows a mast a little over half this height.

I used the rod provided with the Alkem mast as a gudie to cut the brass tube, and even then I shortened it.  I shortened the ladder a bit too.  Still looks to tall.

In other news, I've never soldered a kit together before...!

[Dave V]

I shortened it somewhat by sliding the base back up the mast.  The NJI mast behind it looks so out of place now, one could imagine it to be HO scale...