Hey guys just wanted to supply an update, I'm not sure if anyone is using the RB750UP in this manner or still having problems. But after a couple of years in the field, I can say that the best mod for me has been this third revision. As you know, mod1 was a large 35v 2200uf cap, mod2 was a smaller 3...

Hold on until I post my update later this week, made a change...

Really good work :? The only thing that has POE out ist RB750UP. Now your are telling me that there no feature to see traffic running over the switch? I wonder who is making the design decissions at mikrotik. Who should use the product? The private customer? I can put the 30 RB750 into the waste bi...

So I've spent some time with 5.20, the new PoE firmware, and the "ether1-poe-in-long-cable" option. Some great improvements but I'm still having issues. Instead of the old behavior of reboots and current limit shutdown, with the new firmware I just get reboots. I've got a 35v 220uf capacit...

@complete2006 I had found a similar issue as well (new out of the box). Maybe you guys can duplicate this... load 5.20 and update poe firmware. turn "poe force on" ports 4 and 5 turn "poe off" ports 2 and 3 Now plug a UBNT (radio) device into port 3 and watch 4 and 5 LEDS go crazy.

CoxWireless you say you could have used a smaller capacitor. What size? That level of electrical is over my head, but I was hoping to solder a cap on my 750UP. Is 24V 1200uf reasonable or what would you recommend? I have another RB750UP to modify. I'll go smaller and see where the breaking point is...

Meanwhile....

I would like to report my "hardware fix" has been running perfectly fine in the field now, for what, three months almost. I've got 10 units deployed, all running stable with no device reboots.

This has everything to do with tagging and trunking. In my tests, I was plugging the 750UP ports into a switch (I used port 1 and 2-5, one at a time). I had a different IP on each VLAN on the 750UP. Those VLANs were sent over a trunk with tagging (1 ethernet cable between 750UP and the switch). On ...

With ports 1-5 removed from the master port and put into a bridge, I added the vlan under the switch to ports 2-5. I also added the vlan interface to the bridge. This allowed me to attach an IP address to the vlan. Let me know if you need more information. Yes, but from what you are describing, thi...

This is with the included power supply? Have you saturated all 3 APs to their clients and from upstream to the 750UP for say 30 minutes? How long has your setup been working? How quick was it failing before? Any idea how many AC watts the power adapter is using with everyone running behind the 750U...

This is a little off topic, but does the 750UP support VLAN tagging and trunking? I'm trying to set this up, but keep getting: "failure: not supported for this switch" No, rule table is not supported on 750up. See the wiki below. "Rule table is very powerful tool allowing wire speed ...

This is a little off topic, but does the 750UP support VLAN tagging and trunking?
I'm trying to set this up, but keep getting: "failure: not supported for this switch"

specs of working modified 750UP seen above: OS v5.5 24v PoE injector 200ft of CAT5 cable details of capacitor modification: Radio Shack 272-1020 which is a 35v 2200uF Axial Capacitor positive end of capacitor soldered to positive end of onboard capacitor C14 negative end of capacitor soldered to neg...

probably can, but I had to start somewhere... It still fits in the case, and the axial wires were long enough to reach the locations, so it worked just fine. I think a smaller radial cap would be better and consume less power. I could experiment in the future I guess. But I needed this to work today...

I've been able to resolve my powering issue.

I soldered a 35V 2200uf capacitor onboard (the board still fits in the case) and all is well.
I put this back on the tower 200ft up in the air and now can power 3 UBNT devices!
Finally it works as expected!!!

Can you identify the silk screen location for this chip so that I can manually disable it?

This is already being discussed in another thread, try searching.
Another PSU wont help, even 30v will do the same thing.....

I'm currently running 5.15RC1
Are you referring to something else? If so, i'd love to test it as I have duplicated my problem in the lab and currently seeking work-arounds.

I've been browsing the forum. From what I can collect by MT support, the overload protection is "monitored" in software, and if it senses an overload condition, it shuts off the port...

If this is correct, a simple firmware change could fix our woes....

are you powering the RB750UP via the DC jack or eth port 1?

I've ran into the same problem and have it duplicated in the lab. If the RB750 is powered via a long PoE cable (24v 2A), it can not power ubnt equipment without tripping the over current sensor. I've checked the voltage output at each port (21V using a 24v supply) and ran a current draw check (.14 A...