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I think I have a bad channel on my TIU. I've been running it for about 7 yrs.  My layout. 2 loops, ZW-L for power and a TIU Rev.L.  Power to the Loops are via Fixed 1 and 2.  I've had no problem running either Lionel or MTH engines on the tracks, even with both on the same loop. Last weekend I put an MTH engine on the track and it only ran in conventional mode on Track 4 powered through Fixed1.  But on the loop powered through Fixed2,  it would wait after power up for a command. So, it was receiving a DCS signal after track power up.  Same result. The track connected to Fixed2 passed the DCS signal, the other, nada.   I used the Remote to turn each chanel on an off in the System menu. Same result.  Am I correct in concluding Fixed 1 is Kaput?  Can I fix it?

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Send it t an MTH tech for repair. Not trying to doubt anyone's skills but this is a slightly tricky soldering job and requires testing and repair knowledge to fix. There are several topics, some recent on the details of signal generation testing, soldering, and so forth.

Example very recent topic alking about soldering the ACT244 ICs which are one of the possible failure modes of a DCS channel and weak or no DCS sgnal

Another TIU weak signal topic

Just to be sure and cover the basics:

I do not think you messed with your known track wiring or connections. That said, 2 possible things to check:

First since track1 did not work, and track 2 worked, swap the output channels of the TIU compared to track wiring (track1 to TIU fixed 2 output and track2 to TIU fixed 1) The idea being to ensure the track or say a car or other engine was not killing the DCS signal.

And while doing that, also check track polarity and the type of engine (PS2 VS PS3) engine you are testing. I say this, because PS2 engines care about polarity of the track compared to the TIU output (red to center rail, black to outside rail) where PS3 does not care and works either polarity. Again, there are scenarios where simple as wiring is crossed, a PS2 engine won't detect DCS signal and start in conventional, where a PS3 engine doesn't care about crossed wiring.

Signal failure of a channel can and does happen, just again trying to make sure it wasn't something simple and actual lack of DCS signal.

Last edited by Vernon Barry

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