TIU - Are they repairable?

Contact GGG or Gunrunnerjohn on this Forum. Generally speaking Rev L TIUs are worth repairing.

BTW, Distortion of the case due to heat is usually a sign of a bad connection. In this instance, pictures would be most helpful in pinpointing the problem.

Chris

LVHR

I wouldn't consult anyone but the two persons Chris just recommended.  Do be aware that the nuts that gold the contacts do get loose.  I opened all my TIUs (except Rev Gs, which are soldered), tightened the nuts, and added inside lockwashers atop the existing nuts and then a second lock nut.  These are metric; sorry, I can't put my fingers on the note where I've written down the size.

The H's and I's use these below and I would imagine the L's are the same:

M4-.70 metric nuts 

7mm wrench fits the nuts

Another thing I do is place the wire terminal between the nuts for a more solid connection.

Thanks for the size, Joe.

Henry J. posted:

I have a Rev. L TIU that was purchased new in 2012 (IIRC).  After having some trouble with PS3 Reading T-1, that was sent out for repair, I found a couple of weeks later that all of my PS2 and PS3 locomotives would only come up in conventional mode.  I sent it out to the same service station as the engine and the tech sent it back stating it was 'dead'.

After doing some reading here, I found out about the service bulletin that came out last year regarding an upgrade to the unit. (I did not read the full discussion).

1) If this bulletin had not been complied with, would that cause the failure?

2) Is there a common failure point with TIU's that is repairable?  If so, cost effective?

Note: The area around the power indicator LED seemed on the hot side. I only noticed it because I leaned over the TIU to sniff for a burnt electronics smell (which I did not find). I later opened the case and also found that area of case heat distorted on the inside. (Sorry, didn't think to take pictures at the time).

3) Is there a go to person for testing and repair?

Any advice would be appreciated. Thanks.

 

Your tech probably does not want to deal with TIU.  They can be repaired.  My e-mail is in my profile.  G

GGG posted:

Henry J. posted:

I have a Rev. L TIU that was purchased new in 2012 (IIRC).  After having some trouble with PS3 Reading T-1, that was sent out for repair, I found a couple of weeks later that all of my PS2 and PS3 locomotives would only come up in conventional mode.  I sent it out to the same service station as the engine and the tech sent it back stating it was 'dead'.

After doing some reading here, I found out about the service bulletin that came out last year regarding an upgrade to the unit. (I did not read the full discussion).

1) If this bulletin had not been complied with, would that cause the failure?

2) Is there a common failure point with TIU's that is repairable?  If so, cost effective?

Note: The area around the power indicator LED seemed on the hot side. I only noticed it because I leaned over the TIU to sniff for a burnt electronics smell (which I did not find). I later opened the case and also found that area of case heat distorted on the inside. (Sorry, didn't think to take pictures at the time).

3) Is there a go to person for testing and repair?

Any advice would be appreciated. Thanks.

 

Your tech probably does not want to deal with TIU.  They can be repaired.  My e-mail is in my profile.  G

GGG, I will try to get pictures here tomorrow night and email you.  

Thank you to all who replied! I appreciate the help.

Posting follow up here.  The TIU Rev L was drawing about 1amp when powered up by itself.  Normally it should be about .3amps.  The VR was getting hot.  F1/2 had a signal but weak.  Since op explained that V1/2 were in use at the time, I pulled those buffer chips.  Power Draw went down to .3amps, and F1/2 are a strong 10.

Will replace the buffers on V1/2 which had no output and hopefully that will restore those channels fully too.

So Dead TIU not really true, just wounded.   G

That is awesome to here G!

Thanks!

Henry J. posted:

...

1) If this bulletin had not been complied with, would that cause the failure? 

https://ogrforum.ogaugerr.com/...ion-service-bulletin

Most likely yes.  1) The service bulletin describes a modification to the TIU that better protects the "buffer chips" that apparently failed in your Rev L. TIU.  2) The buffer chips are replaceable and less than a buck a piece (one per TIU channel) so it's a cost-effective repair in my opinion.  3) One thing for sure, GGG knows what he's doing so he'll make the appropriate changes so this doesn't happen again.

Completed and sent an e-mail.  Yes I installed the TVS mod too.  This TIU was an early Rev L with NO TVS.  Not sure that means it can never happen again though  G

STAN2004, are the "buffer chips" the same component as the "signal transformers" mentioned in the bulletin? Would these two titles be referring to the ACT244's?

The signal transformer is a separate component than the buffer chip (74ACT244).  Above photo shows 3 of the 4 TIU channels.

Henry, Have you received my e-mails about your TIU? G

Good evening G.

No I have not seen an email from you. I am just seeing this now. 

Here is the email address just is case, alcofa-2@comcast.net. 

Thanks G!

I have sent several, please check spam.  I do receive your so if you send phone # I can call.  G

GGG posted:

I have sent several, please check spam.  I do receive your so if you send phone # I can call.  G

GGG,

I replied to the last April email I could find from you, with my phone numbers. I did go back and check spam, nothing there.

Thanks, Henry J.

I received it and responded.  I have sent 4 since that first one?  Weird. Will call if you did not get mine. G

GGG,

I finally had the chance to connect the TIU up.  It works great!  Thanks for taking the time to respond to the post and repair the TIU!

Once again, this forum and it's members are great!