Signal Wiring problem

Model Railroader Electronics and DCC
1

Inline image
I have just built a track signal.

  1. Tested the LED’s in the signal to make sure they worked. They worked
  2. Wired the IRDOT-1 as indicated above. Tested Circuit on the bench. Worked
  3. Have now connected IRDOT-1 to Signal on the layout. NO LIGHTS
  4. Checked all connections. Are all correct.
  5. Checked voltage between #1 & # 6. 12V
  6. How can I use a meter to check and see what is wrong? Be specific for connections and values.

Thanks in advance

Harold

2

Correct polarity on 1&6?

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

3

Changed polarity. Same result. No Lights

Next

Harold

4

I don’t see any image indicated above.

BUT if it worked on the bench, AND the wiring is unchanged, then it will work on the table, no?

You get no green light? But you got a green light on the bench?

WHY did you change 1&6 polarity?

Connect meter red lead(+) to 1 and black lead (-) to 6. Should read 12v with NO minus sign.

5

Back to the bench and see if it still works.

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

6

yes :slight_smile:

7

What is difference between the bench and the layout?

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

8

Are you supplying power for the IRDOT from DCC?

The picture we can’t see might be the one from this thread

9

irdot-1 operating train detect and train not detected ledsI don’t know why this image did not copy. I do not want to confuss you. When I said I created the circuit on my bench, it was not the one that went to the layout. The LED’s were hooked directly just like the one, so I see if the circuit worked. Then I used another board on the layout. My next step if I do not find the cause is to take it apart and start again. I made sure I did not solder any wires until I saw it work.

Harold

10

So you duplicated the signal for the layout. Did you check the duplicated signal at the bench?

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.

11

Well, I think the “signal” is just the IR pair on the board, right? Or are they extended off the board? Signal or no signal you should get the green light, right? Sorry, not that familiar with these other than reading up on web[:$]

OK I see one version has 18" leads, and one has IR Pair on the board itself. Which do you have?

12

I did. I have just taken the IRdot-1 from under the layout and checked the connections. They are all in the right place. Over the weekend I am going to first run power to the LED,s in the signal to make sure they are working and built a new IRDOT-1 just to make sure it does not have a bad component. I will let you know how it turns out.

Harold

13

The one in the diagram. 6 leads

Harold

14

You should know, from your second thread, that you will need a resistor, you can’t just hook them up to 12V.

I gather there are at least two IRDOTs one at the bench and one at the layout. The IRDOT or the LED’s could be DOA .

15

Now I am completely confussed. I hooked a clip to the positive side of a 12v Reg DC. I then hooked the other end of the clip to a 1K resistor. With another clip I attached it to the other side of the resistor. I connected the negative side of the 12v to my meter.

  1. Tested voltage at the source Read 12v

  2. Tested at the power side of the resistor Read 12v

  3. Tested on the other side of the 1K resistor Read 12v

  4. Tested at clip at bottom Read 12V

Why am I not seeing a voltage drop?

The red LED is no longer working.

Last week when I was going to see if a LED was working I hooked it direct to the 12v supply and blew the H out of it.

Harold

16

The only thing in your test circuit is the resistor. A resistor doesn’t “use” voltage, hence no voltage drop.

Mark.

17

Doesn’t it mean 12v is going to the LED? Or does it drop the voltage through the LED?

The signal is now on my bench and the red LED does not come on. Tested as above through a resistor Before it was installed on the layout I had tested it and it worked?

How can I test the LED to see if it blown?

Harold

18

No, the LED needs about 3 volts, leaving 9 left over for the resistor, which is where the current calculation comes from. 9mA - 9 volts divided by 1000 ohms. A meter by design puts as little possible load on the circuit as possible, so as not to influence the circuit under test.

–Randy

19

“How can I test the LED to see if it blown?” A 1K resistor in series with the LED, connected across your 12VDC power source. Mind your polarity.

20

A simple check for red and green LEDs is with a multimeter on the lowest range (ohms) across the LED leads. There is enough voltage coming from the meter to make an LED glow.

I bought a cheapo A830L meter off eBay for my hobby needs and it even lights up white LEDs on 200Ω range.

https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=a830l&_sacat=0&LH_TitleDesc=0&_sop=15&_osacat=0&_odkw=a830l

I like it much better than the freebees from Harbor Freight, better features on the A830L.

Edit:

It looks like a mini Fluke too.

Mel

My Model Railroad
http://melvineperry.blogspot.com/

Bakersfield, California

I’m beginning to realize that aging is not for wimps.