I recently acquired a sg300-52mp to replace my sg300-28p.
At first power up the 52mp powered up and I was able to access the webui. I started configuring the switch and it got to the point where the switch needed to save the settings and reboot (I didn't get too crazy with the settings). I waited for quite a while and the switch did not come back up. When I checked on the switch the status light was blinking and I had what appeared to be connectivity on the couple of ports I had plugged in to. I could not find the switch while performing a LAN scan and FindIT application could not see it. I could not access the console (verified I could access console on my 28p so I knew I had the settings correct in Putty). I tried to factory reset by pressing the reset button for 30 seconds (with nothing plugged in to the ports) and the switch would not reset. I tried power cycling the switch (by this time it had been about 30-45 mins after it rebooted) and the switch would not come back online, nor could I access console. I have tried holding reset for 30 seconds, then powering down (still holding reset) for 30 seconds, and then powering back up (holding reset) for 30 seconds and that did not do anything. For the life of me I cannot figure out what happened as the switch simply asked to save settings and reboot.
If I power cycle the switch there appears to be a POST as all of the ports light up and go dark again (like it should). I have tried to plug into the switch and access 192.168.1.254 (factory reset ip) and that does not work. When I plug into the switch my laptop gives itself a 169.254.x.x IP address which tells me the switch will not give my laptop an IP address. I have tried setting a static ip of 192.168.x.x on my laptop and it still cannot see the switch when performing a LAN scan. I should note that if I plug into my switch the Port lights up and flash like there should be connectivity.
When trying to access the console I have utilized the right com port # (system has it set at com8), I have set baud rate at 115200 and tried all of the different baud rates in the putty settings. The rest of the settings are 8 data bits, 1 stop bit, No parity and No flow control. These settings work on my 28p so I know the settings and my cabling is ok.
I am at a loss so I am hoping someone has something to suggest as I am out of ideas.
