Netgear GSM7224v1 Switch Not Booting, Electronic Fault

[Pesle]

Hi all,

So it all started when I rebooted my switch, and it would not come back on and had all lights on and no serial messages. I fixed this as there was a capacitor blown which was apart of the regulator circuit (RAIL 1 In Photo) for the ASIC. Once that was fixed, i started getting serial messages, but they would do exactly what these threads were doing:
https://community.netgear.com/t5/Wired-Network-Adapters/GSM7224v1-Does-Not-Boot/m-p/423784#M932

https://community.netgear.com/t5/Managed-Switches/GSM7224v1-Boot-problem/m-p/406295#M238

One solution was to cover it under warranty would not apply to me as I have replaced the fans with larger ones on the top, and I bought it off Ebay for $20...
Another solution was to try reseting then reflash the Operating Code, which I did using the serial connection, and it did nothing.

Looking further into the issue, the regulator circuit (RAIL 2 In Photo) for the SerDes is returning 0V and a really low resistance compared to RAIL 1.
I have a schematic for the regulator circuit:
https://www.intersil.com/content/dam/Intersil/documents/isl6/isl6444.pdf
So I MIGHT be able to trace it back to a fault.

Just wondering if anyone else has even gone this deep into repairing one of these switches as there's basically nothing online about repairing them or anything similar.
I'll update on what I find.

[Riotpack]

Did you test the other caps? Sometimes they go bad without looking it.

[Zucca]

Thermal camera to see if something is burnig on RAIL 2, but of course you don't have a TIC.
desolder regulator on RAIL 2 and check if it works off board.
connect a Lab PSU in place at VR RAIL 2, slowly ramp up the voltage, check ampere flowing,  and with your fingers if something is getting hot.
I would replace all the caps, with good new ones.

[Pesle]

Sorry for taking so long to reply, I got busy with work and what not. I replaced the other capacitor and I now have voltage. For anyone attempting repair, RAIL1 is 2.5V and RAIL2 is 1.1V (at least for me).
Thank you all very much

[Werecow]

Not quite a necro thread, so...

I use three of these switches; two at work, and one at home.  All three had capacitor failures, intermittently causing the same almost-but-not-quite-booting condition you described.  In one, the six 1,000uF 16V failed, and in another, both 1,000uF 6.3V caps failed. The third switch had only 2 caps fail, both 1,000uF 16V.

I'd strongly recommend that you schedule time to replace at least every 1,000uF in that switch, because they all have the same run time, all had the same amount of heat and stress applied, and they're all the same Teapo brand.  The fact that 'Teapo' rhymes with 'cheapo' is not a coincidence.