If you are looking to determine part number, a sh ver should tell you the exact model number. I suggest that you open a TAC case to troubleshoot if it's a bad switch or a software issue
Switch#show version
Cisco Internetwork Operating System Software
IOS (tm) C3500XL Software (C3500XL-C3H2S-M), Version 12.0(5.4)WC(1), MAINTENANCE INTERIM SOFTWARE
Copyright (c) 1986-2001 by cisco Systems, Inc.
Compiled Tue 10-Jul-01 12:32 by devgoyal
Image text-base: 0x00003000, data-base: 0x00333CD8
ROM: Bootstrap program is C3500XL boot loader
Switch uptime is 3 days, 7 hours, 41 minutes
System returned to ROM by reload
System image file is "flash:c3500XL-c3h2s-mz.120-5.4.WC.1.bin"
cisco WS-C3548-XL (PowerPC403) processor (revision 0x01) with 16384K/1024K bytes of memory.
Processor board ID FAA0412H0NC, with hardware revision 0x00
Last reset from warm-reset
Processor is running Enterprise Edition Software
Cluster command switch capable
Cluster member switch capable
48 FastEthernet/IEEE 802.3 interface(s)
2 Gigabit Ethernet/IEEE 802.3 interface(s)
32K bytes of flash-simulated non-volatile configuration memory.
Base ethernet MAC Address: 00:01:42:FF:09:C0
Motherboard assembly number: 73-3903-04
Power supply part number: 34-0971-01
Motherboard serial number: FAA04109A5L
Power supply serial number: PAC040900QS
Model revision number: A0
Motherboard revision number: 01
Model number: WS-C3548-XL-EN <<<<<<---------
System serial number: FAA0412H0NC
Configuration register is 0xF
