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Does a bad LED open the circuit?

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  • Member since
    January 2019
  • 158 posts
Does a bad LED open the circuit?
Posted by wolfman hal on Monday, October 18, 2021 10:04 AM

One of my Totroise controlers stopped working.

Here is what I am getting.

1.10vdc from power supply

2. 10 vdc across end pins

3. LED's on Control panel out

4. 0 Voltage on line going to Tortoise

If an LED is burned out would that cause this problem?

And if so how can I check it?

  • Member since
    December 2004
  • From: Bedford, MA, USA
  • 21,483 posts
Posted by MisterBeasley on Monday, October 18, 2021 10:24 AM

Yes, a bad LED could cause the Tortoise not to work.  You can easily check by just bypassing the LED with a pair of clip leads.

It takes an iron man to play with a toy iron horse. 

  • Member since
    January 2019
  • 158 posts
Posted by wolfman hal on Monday, October 18, 2021 11:27 AM

Thanks mister B.  That was the problem.  Now I Just have to choose the riht bulb.

  • Member since
    September 2004
  • From: Dearborn Station
  • 24,281 posts
Posted by richhotrain on Monday, October 18, 2021 11:34 AM

Just curious. Did the LED have a resistor on it?

Rich

Alton Junction

  • Member since
    July 2009
  • From: lavale, md
  • 4,678 posts
Posted by gregc on Monday, October 18, 2021 11:48 AM

the tortoise machines draw about the same amount of current an LED requires and needs no resistor

greg - Philadelphia & Reading / Reading

  • Member since
    January 2019
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Posted by wolfman hal on Monday, October 18, 2021 12:11 PM

No.  These were put in years ago.  I will remember to use one now.

Thanks

Harold

  • Member since
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  • From: Dearborn Station
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Posted by richhotrain on Monday, October 18, 2021 12:36 PM

gregc

the tortoise machines draw about the same amount of current an LED requires and needs no resistor

 

Not everyone wires LEDs directly to Tortoises. I don’t. I just wire the LEDs to the center tabs of the DPDTs on my control panels. In that case, resistors are required.

Rich

Alton Junction

  • Member since
    February 2007
  • From: Christiana, TN
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Posted by CSX Robert on Monday, October 18, 2021 1:54 PM

wolfman hal

No.  These were put in years ago.  I will remember to use one now.

Thanks

Harold

 

As Greg mentioned, the resistor is not needed.  If the LED was not wired inline with the tortoise, it would be needed, but if that were the case, the tortoise would not have stopped working.

  • Member since
    September 2004
  • From: Dearborn Station
  • 24,281 posts
Posted by richhotrain on Monday, October 18, 2021 3:54 PM

wolfman hal

3. LED's on Control panel out

I remain curious.

Are all the LEDs "out" on your control panel?

Rich

Alton Junction

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Monday, October 18, 2021 4:24 PM

I've had a couple of the indicator LEDs fail on some of my Tortoise iinstallations. Yes, they open on failure. One downside to the "supply chain" for model railroaders is that much of the discounted electronic components available to us are not exactly certified, first-quality products.

Being in series, anything within the circuit, including other panel LEDs will also be extinguished. Sure, there are several methods to wire indicator and/or signal lights to a Tortoise but the in-series arrangement is a quick and easy solution.

I use two lead bi-color LEDs and in some cases I have up to three daisy-chained along the circuit. With over a hundred Tortoises I've probably only had two or three LEDs fail in 25 years.

I keep dozens of bi-color LEDs on hand. Some red/green and others red/amber both in 5mm and 3mm. For signaling and frog powering, those that are not powered off of Frog Juicers, I do use the auxiliary contacts on the Tortoise.

Good Luck, Ed

  • Member since
    January 2019
  • 158 posts
Posted by wolfman hal on Monday, October 18, 2021 4:47 PM

No. But each toggle had its own curcuit.

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