TIU not recognized by computer

Hi, looks like a REV G and they were junk no fuses and traces burn up underneath the bottom board, generally non reparable! also memory chip failure and no memory chips available anymore!

Alan

I never saw that message when connecting to a TIU using the serial cable.  It's odd the WIU connects to it but the computer won't.  Can you connect to the TIU using the DCS remote?  If so, reset it so it's back to TIU #1 with all factory defaults and see if that helps.

I did a reset with the remote and it didn’t correct the issue.  I guess I’ll keep it for parts.  I have another TIU but it has issues too.  It connects but can’t seem to find locomotives in the track.  When trying to add a loco I get a “no loco on track” message.  It connects to the computer and WIU without issue.  It’s REV i3b?  Any ideas on a possible fix for that issue?

@Rod B8s posted:

I have an older version TIU that is not recognized by my computer.  I’ve connected several TIU’s using the same cable with no issue.  I first noticed the problem when trying to connect a WIU to it via the serial cable.  It takes quite a while for the WIU to recognize the TIU.  On occasion it will connect within seconds….  I was going to try and update the TIU but have been unsuccessful in getting it to connect to the PC.  I noticed when doing an auto search the status says “unlocking”.  Is there a way to unlock the TIU and maybe it will connect?  I’ve added a video and photo of what I’m talking about.

In your picture you are missing the 1/8th in headphone jack plugged into the audio ports. That is what puts the TIU into booloader mode.

@Rod B8s posted:

I did a reset with the remote and it didn’t correct the issue.  I guess I’ll keep it for parts.  I have another TIU but it has issues too.  It connects but can’t seem to find locomotives in the track.  When trying to add a loco I get a “no loco on track” message.  It connects to the computer and WIU without issue.  It’s REV i3b?  Any ideas on a possible fix for that issue?

In the past when I had a suspect TIU, especially one with DCS signal problems out of the channels, a blown or damaged ACT244 driver can "load" the 5V logic power bus in the TIU and cause issues -especially if multiple ones are blown. In one case all 4 were blown so hard and loading the bus that TIU would not boot up. Point being, removing damaged ACT244 signal drivers in a damaged TIU might "clean up" the logic power supply and possibly be one less obvious problem?

I've also found powering the TIU and plugging and unplugging the audio cable loopback forcing the unit into booloader while the PC is attempting to connect allowed for updating a problematic TIU.

Again, a theory. The TIU that the PC cannot connect to, but a WIU can, possible answer for that is the TIU is failing to go into bootloader mode for PC connecting and updating firmware. The audio loopback cable is what is supposed to tell the TIU to kick into that bootloader mode- so a bad connection, broken or dirty jack, bad cable, cable no seated fully, cracked solder joints- are all things that come to mind.

The WIU connects because in that mode the handshake and response is to the normal running firmware mode and did not require bootloader mode.

Thanks for the info Vernon.  I was using the headphone jack when attempting to connect via computer.  That photo was taken after I was done attempting.  The WIU connects but not right away like it does with my REV L and the other REV i3b version.  Where is the ACT244 driver you are referring to?

@Rod B8s posted:

Where is the ACT244 driver you are referring to?

There are 4 of them, one for each channel. https://ogrforum.ogaugerr.com/...-aghr-and-mth?page=1

https://ogrforum.ogaugerr.com/...-dcs-signal-from-tiu

Topic with picture showing 4 locations.

https://ogrforum.ogaugerr.com/...88#79142442782414388

Rod, you didn't mention what kind of computer you are using or the cable.  In your screen shot I see that it is searching for the TIU on COM6.  Unless you have a myriad of devices connected to the COM ports, that doesn't seem right.  I wouldn't trash the TIU until I checked the serial connection to the computer.

Dan I do have several devices on that PC.  I use it to program DCC locomotives with ESU and JMRI.  It will successfully connect on my REV L REV i3b and REV G TIU’s using COM 6.  Another issue I noticed is a locomotive starts up as soon as power is applied with my REV i3b TIU that can’t find a loco on fixed 1 and 2.  I guess I need to send it to someone to evaluate…

Before you tried to connect the TIU to the computer, did the TIU work correctly?

Are you using a USB to serial cable?  If so, does your computer see a device on that USB port?

Is it only one locomotive that starts up when power is applied or is it all of them?

Dan,

I was able to get the REV i3b TIU to connect to my PC and successfully updated to 6.10 (I removed power and then reapplied while it was trying to find the TIU).  The locomotive startup issue is with all locomotives and on both fixed outputs.  At power up the loco starts up.  I currently have a HO locomotive for testing purposes, and it starts moving after about 15 - 20 seconds.

All locomotives would indicate that you are not putting out the watchdog signal and, perhaps, any signal.

Make sure the radio board is firmly seated.  Beyond that you may need to send it to a tech to look at.  Indications are this is an old model and may not be repairable.  On the other hand, the few TIUs for sale are listed for fantastic prices and the new WTIU will be late.

Hi if the engine starts up immediately on power up tiu is not working and engine is starting up in conventional! tiu dcs has no signal no watch dog so trains start up immediately need tiu repaired!

sounds like your REV i3b has no signal and might be able to be repaired!

Alan

I can replace board components if I can get some guidance.  The MAX chip has been replaced with no resolve.  

I was able to successfully repair the REV i3b TIU!  Two of the ACT244 chips were shorted causing the signal issue.  I purchased a hot air station and successfully replaced the two chips.  I appreciate all of the help!

@Rod B8s posted:

I was able to successfully repair the REV i3b TIU!  Two of the ACT244 chips were shorted causing the signal issue.  I purchased a hot air station and successfully replaced the two chips.  I appreciate all of the help!

Baby that TIU, there are no more coming!