Cisco 2960G Switch teardown an detailed overview for CCNA lab and repair -Part2
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- เผยแพร่เมื่อ 5 ต.ค. 2024
- Complete tear-down and overview of a Cisco 2960G gigabit switch for CCNA candidates and also for IT repair technicians.
At the first half of the video I go over the main components which are the Flash, NVRAM, Route-Processor and ASIC from the perspective of a CCNA. On the CCNA exam you do not need to know such details, but it helps you to be able to visualize the data flow, and to give you a rough idea about the hardware.
In the secon half of the video I go over the mainboard components in deep detail, and explain their functionality within the Switch. This part is going way beyond CCNA, instead it caters for component-level repair technicians.
If you are interested in the disassembly and the PSU, watch Part1 of this video series:
• Cisco 2960G Switch tea...
Some portions of ot the video got lost because of the Kdenlive Linux video editor, sorry for the choppy video.
Parts list for the Mainboard discussed in the video:
====================================
Route Processor: Cisco Yeti2 (IBM Power-PC 405 core + FPGA)
Flash: Intel TE28F128
NVRAM: Flash emulated (no dedicated chip)
RAM: Micron 46V32M16 64MB DDR modul
TCAM table: Renases R8A20300ABG
ROMMON I could not find the chip holding the boot-ROM
Serial Console: MB3232I
ASIC from Cisco
Parts list for the other components:
====================================
U67 IR 0901 A6P3N6 (is there a datasheet?)
U76=U77 Maxim 8566E
U67=U66 Maxim 8643E
U64 ISL8700IBZ
U46=U61=U2 SN74LVC245A
U70=U32=U33=U34 SN54HC595
U7=U83 P149FCT20807HE
U81 ADTT75A
U6 CY2CC8100-XT1
U84 UD8808265 (is there a datasheet?)
U54=U53 SN74LVC126A
Q20 NE47810S DDR Double Data Rate linear regulator
U14 MB3232I
U82=U68=U69=U47=U48 7Z25L = NC7SZ125M5X
Most of so called network engineers nowadays are just network technicians. If one wants to become a network engineer then it should follow the footsteps of this man. Great work to you!
Nice!! Really interesting! Does worth it to get an old switch to get some components? Which one you would get from it?
Do you get any output from the console?
Which LED is stuck on green? Does any of the LEDs blink before going solid?
Those which are stuck on green from the very first moment you plug them in without producing any console output are mostly bad RAM.
I actually have a couple of those (2960G with stuck green) and I intend to do a howto-repair video on them.
Hi, thanks for replay! No output from the console port at all. The System LED is the one stuck on solid green right after i pluged the power cord! No other LED's blink or lights up at all. Only the SYST LED. I Googled 3560 v2 chematics and couldn't find, I wanted to test the components. The power supply is working and there is no bad capasitors or resistors, I tested it with True rms fluke 287 meter. It would be a great help, if you do a video how to rapair one. Thanks Again!
Hi, really a gold nugget. Could you be so kind to tell me where is the ROM?
what is the purpose or the usage of those contact near the White plug for power supply
i mean those named " P " and have 6 and 15 contacts ??
great video! Is there a way to reset the flash on the board?
I have some Cisco Catalyst 2960X-24PS-L - switch that powers on fine but no LAN port indicates network traffic light after its switched on and after a long time, some will restart by itself again and its unusable. Please what do I do?
Hi, it's a very interesting video. Do you know about any more documentation about this Yeti-2 CPU?
I wish I would have more information about these devices, since I consider Cisco stuff to be fascinating.
As I understood, these are based on IBM Power-PC, and Cisco was investing lot of effort into putting more features into the CPU. Though, as usual, in the case of a switch, the real "grunt" is in the Cisco ASIC, paired with the database chip, which is also an ASIC on its own league.
at 26:00, your mystery component is a LV810 from ICS, you can find documentation here : co.yic-electronics.com/datasheet/69/MK3807-01RITR.pdf
Hi, thanks for the good Videos, and good explained too. I have 3560 v2 which does start when plugged on AC power, but the SYST led stack on solid green right after booting. Any ide what it could be?
If you are sure that the power supply is good, the issue you describe sounds like RAM chip failure (90% of the time) or the onboard flash chip have failed, and the ROMMON is not being loaded. Thus, one need a good hot air reworking station, or an infrared reworking station. One can try to replace the RAM chip without such a thing, but it would require hands like a surgeon. Therefore, I will be using my Honton HTR 290 reworking station to try to repair similar issue. I will definitely upload the video once I have time next to my job to do the repair.
Hi, I tested with another power supply of a the same 3560 working one just to clarify that the issue is not from PSU. I blieve fault is from the RAM chip, I used bit of time testing the SMD's, Capasitor, Mosfets, indoctors and Resistoers. All tested components gives the same output result wich is good. I guess I have to give a try testing the DDR RAM. As you said it could be some issues with the RAM.
If the PSU is known good, no output from the console, and the system turns instantly green, that sounds like RAM chip failure to me. However, if you intend to replace the RAM, you have to use the specific model used in the switch, and they are not easy to get. Best option is to buy a working RAM module stick for a Cisco ASA. The ASA series of firewalls used the same RAM chips as the ones in the switches.
The situation is, that using equipment what is normally available for small repair shops, you simply do not test the RAM chip at all. You just remove and replace it with a known working chip. I know this sounds surprisingly ignorant, but even large repair shops do the same procedure, because testing it would cost more than replacing it.
Hi i have a 2960G series which have all the system leds and de GB ports in green and dont blink. Someone tell me that maybe is the NVRAM Chip, how can i identify it? Thanks a lot!
What is the console output on the switch?
@@DonkeyLearningIT have not console output just black. Thanks
@@Quemero32 If there is nothing on the console, then that is indeed hardware problem. However, I would assume that something is off with the power supply, or with the ASIC. The NVRAM rarely fail. In fact, these switches do not have separate NVRAM, but instead they use the flash to simulate NVRAM.