Hello my TIU variable 1 output has a constant pass through output voltage of 18v. I tried TIU reset but still shows this voltage. This occured after a derailment. Should I try a remote reset?
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I suspect that one or more of the FET's in channel 1 have shorted. @GGG will be happy to fix it for you. 
While it could be the FET(s), a failed TVS in each variable channel can give the same symptom (output stuck on and not "variable").
I would check for both types of failures.
https://ogrforum.com/...l-variable-2-failure
Hello thanks for the quick response. Do you know the part number of the TVS and FET's? I retired from the office machine repair business 8 years ago where I used to do component level repairs. The FET's look like TO220 packages. Thanks for the help!
I found the TVS number from an earlier failure I had. I just need the FET number.
Thanks
Actually, that TVS is a higher voltage rated part than the four on the output of the channels, so I'd check to make sure. I believe it's a 50V rated part.
Yep, 51s to be exact.
@Vernon Barry posted:
FETs are likely IRFZ44- but as a policy, always read and get the number off the part you are replacing.
