[solved] No lights on topside adapter

solved
sos
electronics

#1

After a successful build, we were able to make everything work for a while, then started to have a problem with the topside adapter going dark (all three lights out) after about five minutes. Finally it has gotten to the point that none of the topside board lights come on at all. (We have a version 2.6 ROV with version 2 Tenda boards).

Although we have no lights on the topside board, the ROV starts up normally (judging from the lights and expected startup sequence) but of course we have no Ethernet connection.

I have replaced both the Tenda homeplug boards, mashed the connectors together to ensure good contact and generally messed about with no change in the symptoms, so now I’m stumped! Any suggestions?

Thanks - this is a great project and we have had a ton of fun putting it all together - now we want to dive! Dive! DIVE!


#2

I’m surprised that you don’t get at least a power light from the Homeplug Adapter. You might want to probe around a bit with a multimeter and see if the 3.3V regulator on the topside adapter board is still functioning.

You can download the schematics for all of our electronics off of our GitHub site- see the “Open Source” tab on our home page.

-W


#3

A bit more detective work and I think I’ve figured it out. I put a meter on the output of the regulator looking for the 3.3v and sure enough - not there. A bit closer inspection showed that I let the magic smoke out of the regulator chip somehow.

New topside board required I’m afraid!


#4

Got a replacement 3.3 v regulator from DigiKey and I’m back in business!


#5

Nice. Puzzling as to why the 3.3V regulator failed, though. There’s not a whole lot of loose wires or things to short out- it’s just powering the homeplug adapter. If the regulator failed, does that mean one of the homeplug adapters is bad?

I’d proceed very carefully with the new regulator. Keep your finger on it when you first power it on, and if the thing starts getting hot, shut it down and investigate further.

-W


#6

No idea why it failed, but I did replace the Homeplug board too. Before it failed (with the old Homeplug) it would run for a few mintues then shut down - like the regulator was going into thermal overload? At any rate, it seems to be stable now, so I will retire the suspect Homeplug adapter and stick with the new one.

Thanks for your suggestion - got me on the right track!


#7