DCC Track Tester - a different take

[John]

[Scottl]

That is a good idea, very handy

[jagged ben]

It's not a DCC tester though, it's just a voltage tester.  Works about as well to tell you if you've got DC on the track, although for that purpose a handy additonal LED could also tell you the polarity.   The one thing this certainly won't help with is testing DCC polarity if you're troubleshooting reversing blocks.  That's why you need an expensive gadget tester. 

[John]

If you want to split hairs, sure - it tests for voltage - in the this case, it displays that there is a DCC signal since the LED is on the entire time - if it were DC it would only be on when the diode is facing in the correct direction across the rails and there is a voltage.   I normally use a VOM set to AC ..

The point is the guy used a few inexpensive parts, and something from the junk box to allow him to test his track in an easy peasy way.  I thought it would be of some value to share with the folks here.

 The one thing this certainly won't help with is testing DCC polarity if you're troubleshooting reversing blocks.  That's why you need an expensive gadget tester. 

Not necessarily .. you can test the polarity by placing a light bulb ( or diode/resistor) across the main and the reversing section .. https://wiringfordcc.com/track.htm#a2


If you want to build a (cheap) tester --- https://forum.mrhmag.com/post/dcc-polarity-tester-12196234   this should work

[Maletrain]

I just use an automotive LED bulb, one that has the contacts on the ends of a glass tube.  The one I use has 2 diameters of the contacts, one that works perfectly for N scale and the other for HO scale.

I can tell if there is voltage between the rails by bridging the rails with the bulb.  And, I can tell if there is opposite phase/polarity across a rail gap by touching the contacts to opposite sides of the gap for the same rail.

If I was going to build something like this, I would probably make it more complicated to be more useful.  For instance, I would separate the pickups from the 2 wheels on each side so that there are 4 independent pickups, and then put LED's across the leading pair to see track voltage and from the front wheels to the ones behind on each side to see if there is any our-of-phase situation across gaps.

Something like that might help me more quickly see issues in turnouts, where light bulb contacts aren't where you really need them.  And, it still doesn't tell me which rail is dead, or if they are both dead.

So, I usually go for a multimeter when I really need to diagnose a problem, and would probably not build something like this at all.