Accessory switch controller problem

I had a problem with my ASC, so I sent it back to Lionel, (A bit costly from the UK) but they sorted it out no probs. and FOC so a bonus. I think Lionel Service are great, been so helpful to me in the past, even over "stupid" questions from me. (I am 70 and not used to this way of driving model trains)

I guess try reprogramming it as a last resort before sending it for repair.

Move the wires to switch 6 and see what happens.

I had an issue with the SC-2 when using track power and cutting the trace for position #1. That position chattered whenever the non-derailing track was enabled or the controller. But it did stay where I put it. I decided to just do the TMCC mod to those particular switches, the ones on the first position of the SC-2, and not use the first position.

Use an ohmmeter to check for zero resistance across the Out terminals with no switch connected to the ASC.   Check both with and without power applied to the ASC.

If there is a bridge across the contacts with power off or on, the Out relay's contacts could be stuck.  (First repair attempt would be a sharp slam onto the table to jar the contact loose!)

If there is only a bridge when power is applied, the circuit driving the relay is shorted and applying constant power to the Out relay coil.

Hi Dale,  Haven't talked to you in a while.  I will do the tests yoyu recommend' but , I have already purchased 2 new 78-1639-250 ASC units .  Loojks like a simple drop in replacement accept for the dat com connections.  My IC Controls units have two terminals for dat and com.  The new units have 5 pin connectors labeled PDI.  I need to know which pins are dat and com so I can splice the ends of the cables to my daisy chain with the old IC Control units.  If I cant do that I am screwed.

          Help please!!

I measured my PDI cable that connects to the 9-pin Dsub on the Base, coaxial power supply and 5-pin PDI connector:

PDI pin 1 = Coaxial power center pin +V  - Dsub not connected

PDI pin 2 = Dsub 3  Serial receive into Base

PDI pin 3 = Dsub 2 Serial send from Base  --> splice/tap to TPC, etc.

PDI pin 4 - not connected in this cable, side-by-side PDI connectors on accessory devices bus pin 4 directly between the connectors

PDI pin 5 = Dsub 5 (ground/common) & Coaxial power outer ring

I hope this helps!

What brand are the switches. There was a post by a fellow having trouble with Atlas switches. His analysis indicated a problem with the wiring and/or the Atlas anti-derailing modules.