Skip to main content

Replies sorted oldest to newest

The Explorer takes about a full minute to fully boot up.  The track light will illuminate RED about 45 seconds into the bootup process and the WPS light will stop flashing about 5 seconds after that. Does the WPS light never stop flashing?

For reference this is the complete bootup & track power down process of the Explorer:


Videos (1)
mth explorer indicater lights
Last edited by H1000

Can you log into the LUCI interface and then flash the latest firmware?

It's either firmware or hardware- this is what this "test" attempts to prove.

Instruction manual here , instructions for accessing and updating being on page 9 through 13


Images (1)
  • mceclip0
Last edited by Vernon Barry

Before reloading the Firmware, I'd try a factory reset.

The book has instructions on this but this is the procedure I use when doing it to make sure it goes without fail:
1) power up the Explorer and wait two minutes
2) using a modified paper clip, press the Reset button (firm click can be felt), for at least 10 seconds and release.
3) wait two more minutes and then unplug & replug the power to the explorer.

You've got nothing to lose by trying this.

After the reboot, the red track light flashes.  But still no signal to track

Of course there is no signal to the track, because there is no power to the track- the red light flashing indicates over load AKA shorted output.

Screen Shot 2024-01-26 at 7.48.36 AM

Disconnect any wiring to the output (red and black posts), and then use the add engine command to attempt to turn track power back on, to determine if the short is external or internal- like a blown TVS.

If no wires are attached to the posts and it still flashes red- then the mainboard inside the explorer likely has a TVS on the output that failed from voltage spikes on your track.


Images (1)
  • Screen Shot 2024-01-26 at 7.48.36 AM

Bingo!  The Explorer was not/is not connected to the track.  Is the TVS a user-replaceable item?  I have a bunch of them on my parts bench.

It probably is. Here's the issue, while I have messed with the explorer and have a good idea of the internals, I do not have one in front of me at this exact moment. I can borrow one later this afternoon.

So, I do not have pictures of the main circuit board to help you identify the suspected TVS that may have failed. Further, it might be more damage than just the TVS, I was trying to list simple reasons somewhat knowing the circuit what likely could happen. I do not claim to know everything there, I have no fully reverse engineered it- knowing just enough to cover some basic high level concepts.

Again, knowing how the MTH TIU is built, knowing how even the IR comander is built, I would most definitely think there likely is a TVS on the output and again, knowing how they fail typically shorted- that's an easy match to the current symptom.

Sorry it took me so long to get back to this. I needed and wanted to document the Explorer circuit board, because to my knowledge, I've never seen anyone show it.

In the below photo, the upper left area is the power control area with 2 large SMD MOSFETs and a TVS diode right next to and in parallel to the red and black wires.


The TVS on the output is again the B516 BFG marked device, and researching that, I believe it to be a Bourns

The style of the B matches the company name logo

Specifically a 1.5SMBJ28CA BFG

working voltage 28V

Clamp voltage 59V


Again, I would check, with power off to the device. if that appears shorted using a meter. You don't even have to open the housing- just test using a multimeter for continuity across the red and black output posts. If that TVS has failed shorted from voltage spikes- it would show shorted at the output jack.

Further pictures of the power circuit for those interested.



This TVS is nearer the power entry edge of the board but is the same part number as the one on the output.


This is the bridge rectifier and possibly another TVS on the logic power section.


Last, mouser has the exact TVS from Bourns, but you can find at other suppliers and or many other similar equivalent TVS diode.


Images (8)
  • IMG_4112
  • mceclip0
  • IMG_4114
  • IMG_4116
  • IMG_4117
  • IMG_4119
  • IMG_4121
  • IMG_4122

Again, a TVS may not show any "physical" damage or burn marks, and still be failed internally. They typically appear as a short or low resistance to a meter.

Given the symptom of the Explorer track power light flashing red- even with nothing connected to the output posts possibly indicates a failed TVS as a guess.

Otherwise, it could be a deeper failure and probably beyond the scope of simple repair.

DCS explorer TVS


Images (1)
  • DCS explorer TVS

Add Reply

The DCS Forum is sponsored by

OGR Publishing, Inc., 1310 Eastside Centre Ct, Suite 6, Mountain Home, AR 72653
800-980-OGRR (6477)

Link copied to your clipboard.