2.5v rail loss
Posted: Fri Nov 18, 2022 4:42 pm
Product: WS-12-250-DC
Cause of Failure if interested
I seem to have lost the 2.5 volt rail on the main board.
Both switches are out of warranty (19' and 20' vintage)
They both go through the PSU boot sequence (LED) and then Turn on the Front Power LED, and the Fan jiggles.
Internal PSU is putting out 50.1 volts, so I don't think a replacement PSU is the fix. Please correct me if I'm wrong
The Main board is putting out 24v rail, and the 3.3v-D, 1.8v-D, 1.0v-D rails but I get nothing on the 2.5v-D rail.
My assumption is that the "-D" is a digital supply rail and the Buck converter [U20] that seems to make 2.5v from the 3.3v-D rail seems to be busted.
Is this correct; that the loss of 2.5v-D would halt the boot process? or is the 2.5v rail startup later boot process than I'm getting to?
Is there a repair process for this type of failure? (there are no replacements to BUY!!!)
Cause of Failure if interested
- Code: Select all
Tower site partially when offline, due to loss if communication with switch. Router still had HW link and all POE/Link lights were still on, on the switch
Rebooting the switch stops just after the front power LED comes on. No fan startup sequence, no POE or Link lights.
Programed a second unit with a Config backup, tested dry at desk. Replaced with switch in field.
Blows 7.5 Amp fuse-ed supply.
Unplugged all tower radios, only connect two local devices (local phone, and router) switch works fine.
Plug first cable (#1) into port 1. Arc-ing noises and burning smell. Remove cable. Switch is still powered up. plugin all other ports. Still powered up but is non functional
Reboot switch
Stops boot process at font light, no fan sequence.... failure identical to original switch
I seem to have lost the 2.5 volt rail on the main board.
Both switches are out of warranty (19' and 20' vintage)
They both go through the PSU boot sequence (LED) and then Turn on the Front Power LED, and the Fan jiggles.
Internal PSU is putting out 50.1 volts, so I don't think a replacement PSU is the fix. Please correct me if I'm wrong
The Main board is putting out 24v rail, and the 3.3v-D, 1.8v-D, 1.0v-D rails but I get nothing on the 2.5v-D rail.
My assumption is that the "-D" is a digital supply rail and the Buck converter [U20] that seems to make 2.5v from the 3.3v-D rail seems to be busted.
Is this correct; that the loss of 2.5v-D would halt the boot process? or is the 2.5v rail startup later boot process than I'm getting to?
Is there a repair process for this type of failure? (there are no replacements to BUY!!!)