MTH ITAD 40-1028

Charly posted:

 

 It turns out that the common of the aux power is tied to the common on the back of the TAD and will not trigger the signals.

Apparently you used a meter to confirm this.  Just for the record, which "AuxPower Input" terminal on the ITAD (left one or right one in photo) is tied to the "Common(-)"  terminal on the back?

Presumably you are connecting the 153 common wire to Aux "hot", 153 red wire to ITAD NO, and 153 green wire to ITAD NC.

Assuming the ITAD itself works as confirmed by your last experiment, I can think of 2 scenarios.

1. The AuxPower Input is hooked up backwards so that the ITAD is actually switching Aux "hot" to the NC and NO terminals on the back.  A symptom of this would be red or green lamp are both off when powered since NC and NO would be sending a voltage the 153 already has on its common wire.   Can you hear the faint relay "click" when the ITAD is triggered?

2. The rocker switch or associated internal wiring which selects Track Power or Aux Power is broken - allowing only the Track Power side to supply power to the ITAD.  That it works with a different power supply might be explained by a swapped wiring like in scenario 1.

stan2004 posted:

Charly posted:

 

 It turns out that the common of the aux power is tied to the common on the back of the TAD and will not trigger the signals.

Apparently you used a meter to confirm this.  Just for the record, which "AuxPower Input" terminal on the ITAD (left one or right one in photo) is tied to the "Common(-)"  terminal on the back?

The left terminal off AuxPower show continuity with the common(-) terminal on the back.

Presumably you are connecting the 153 common wire to Aux "hot", 153 red wire to ITAD NO, and 153 green wire to ITAD NC.

Assuming the ITAD itself works as confirmed by your last experiment, I can think of 2 scenarios.

1. The AuxPower Input is hooked up backwards so that the ITAD is actually switching Aux "hot" to the NC and NO terminals on the back.  A symptom of this would be red or green lamp are both off when powered since NC and NO would be sending a voltage the 153 already has on its common wire.   Can you hear the faint relay "click" when the ITAD is triggered?

If I wired the hot(+) power to the left terminal of the AuxPower I got no lamps lit.  If I connect the hot(+) power to the left terminal and common power(-) to the right terminal I get lights and no trigger.  If I connect connect the hot(+) power to the left terminal and common power(-) to the right terminal from a different power supply i get noise and flickering, but no trigger.  Reverse that for a different power supply and lights no trigger.

2. The rocker switch or associated internal wiring which selects Track Power or Aux Power is broken - allowing only the Track Power side to supply power to the ITAD.  That it works with a different power supply might be explained by a swapped wiring like in scenario 1.

If just power is connected to the ITAD without any accessories connected, using the AuxPower the ITAD triggers.

As the frustration level of this project rose and the cost factor of the now used nonreturnable ITAD stimulated the frustration, I opted to connect the signals, block and semaphore, to a mechanical TAD and will just press it to trigger the lights.  Maybe a motion sensor scenario will be in the future, but for now, the lights are working manually.  I did manage to char the green bulb, however, but no worries, I can get a new one at the store tomorrow.  The problem is that they are a PITA to change

So what is the career path of your MTH ITAD? 

As you may have read in the contemporaneous thread about the mis-behaving 153IR ITAD, it was actually defective and essentially un-repairable.  If you're just going to "deep-six" the ITAD,  I'm pondering how I can get my hands on it as I've never seen the insides of an MTH ITAD.  I would of course report my findings to the forum for the greater good so to speak.

It has gone back to the store to be returned to distributor as defective and I got my money back.  That was enough to pay for a new signal.

Cheryl, you might want to fix your signature.   This is what we see now.