Bad TIU Channels?

Definitely try the bulbs.  It is weird that 3 of 4 are bad.  Has this TIU been used a lot?  G

Chris:

You can also search for Engineered Filter here on the forum.

1) They use no power, the bulbs burn power BUT give a sign the track is powered.

2) They fit under the track or between ties, virtually invisible.

This TIU has been used on and off for six years.  Perhaps it always had a problem.  I never thought to check into signal strenth until this layout.

I think that I will try a few bulbs and if that works, I will make the filters.  I have my doubts.  The test was done using the same 40 inch section of track, engine and transformer on each channel.  I would expect that the "bounce back" issue would be present on all channels.  Since fixed 1 has a perfect signal level, I would not expect filtering to help the other channels but that is only my guess.  If this all fails, I will probably be in the market for a rev L TIU.

Chris

To follow up on this topic: I tried two 18v light bulbs (one at the TIU output and one at the end of the test track) and had very little to no improvement in signal strength.  Occasionally I would see one level higher than the levels I witnessed without the bulbs.

To me, this concludes that the TIU itself has problems and I will mostly likely now try to find a new REV L TIU.  I did un-mount this TIU and found that it is a REV I3A.

If anyone knows of any other fixes to try, then please let me know.

Thanks,

Chris

Chris,

this TIU and found that it is a REV I3A.

That's most likely your problem.

Many Rev I3a TIUs (including one of mine) came from the factory with a defective component that caused signal strength degradation on all TIU channels.

If it was serviced for this problem there's a little silver or white dot next to the rev indicator. MTH may still be treating these as warranty issues, however, you'd have to call MTH to be sure.

Thank you Barry, that information makes me feel better about purchasing a new TIU.  I would go the warranty route, but I would rather have all of latest improvements in the REV L.  Besides, this one still works great for holiday layouts!

Chris,

Regardless, why not look into a warranty repair? If you do purchase a new Rev. L, a repaired Rev. I3a would make a good spare and backup, or be available for layout expansion.

If MTH does treat it as a warranty repair, all it'll cost you is one-way shipping to Columbia, MD.

I took your advice Barry, and MTH is performing a warranty repair.

I also purchased a new REV L TIU which is now installed and working perfectly.

Thanks everyone.