insideGadgets

Today we’ll be taking a look at the Dell Power Connect 2124, a 24 Port 10/100 Switch with 1Gbit uplink. It’s got the capability of a redundant power supply and has 2 fans on the back, it’s a fairly old switch dated back to 2003.

A few screws later and we’re in.

It’s a pretty dusty unit, we’ve got our power supply on the left which gives out 12V at 4.5A that connects to our main board and from the main board we have some cables running to the front panel. They’ve cut the board a little bit around fans to allow for better air flow.

We’ve got a pretty large Broadcom chip in the middle that was under a heatsink – probably one of the largest I’ve ever seen and there’s heatsinks on each Broadcom PHY chip. If you look closely you can see the capacitor on the bottom right hasn’t been soldered down properly and the inductors nearby are a little like that too. There’s a whole heap of 74 series logic on the left which go off to the front panel. On the bottom we’ve got a fair few passives and a nice looking line of them too.

The RPS power comes directly to the main board, goes through a ferrite bead then through a MBR2535CT Schottky barrier rectifier, the 12V coming from the power supply does the same thing, so I believe they are using the rectifiers to join both power supplies together. After that we’ve got 2x CS5161 Synchronous buck controllers with 2x NTD4302 N channel mosfets each; there’s a place where they could add another one of these if they wanted to. Apart from that, we’ve got 2x AP34063 SMPS on the right of the board.

1. Broadcom StrataSwitch II Integrated Multilayer Switch
Supports 24 10/100 ports and 2 10/100/1000 ports with 256KB data packet memory which can be extended to 4 – 64MB. The PDF shows you can add 4x 2Mx32 SDRAM with the BCM5238 PHY. Running from an 133MHz oscillator.
BCM5616A1KTB

2. ESMT 64Mbit SRAM
They’ve only populated 2 out of 4 of these.
M12L64322A

3. Broadcom 10/100/1000 Gigabit PHY
BCM5421

4. Broadcom Octal 10/100 PHY
BCM5238

5. Winbond 8bit MCU
A microcontroller which is compatible with standard 8052 and has 64K of flash, 512bytes of RAM, 3 timers and 32 GPIOs. Running from a 24MHz crystal.
W78LE516P

6. Alliance 4Mbit SRAM
With a 74HC373 Octal D-type latch nearby
AS7C3256

7. Pericom chip
Looks like it could be a PLL from what I’ve read and it makes sense as none of the 3x 100Mbit PHYs have any crystals on them.
P16C185

8. ICS Clock Generator
With 25MHz crystal
ICS333M

9. 74 Series Logic chips
Fairchild 74VHC139 Dual 2-to-4 Decoder/Demultiplexer
Ti 74LVC08A Quadruple 2-Input Positive AND Gates
Philips 74HC164D 8-bit Serial-in, Parallel-out Shift Register
Philips 74HC32 Quad 2-input OR Gate

For the front panel board we’ve got an Xilinx XC95144XL CPLD with 3x more 74HC164. With all the 74 series logic they had on the main board, I wouldn’t have thought that they needed any more logic or a CPLD.

And that’s all.