直流電壓測試 | 1 | 將紅色測試棒插入“V/Ω”插座，黑色測試棒插入“COM”插座。 | | 2 | 旋轉開關轉至DCV區域。（若不知道待測電壓的約略值，則轉至最高檔，再依實際測量值轉至最佳解析度為止，最大電壓勿超過 DC 1000V。） | | 3 | 將測試棒與待測線路並聯。 | | 4 | 從液晶顯示器讀取待測電壓值。 |
交流電壓測試 ACV | 1 | 將紅色測試棒插入“V/Ω”插座，黑色測試棒插入“COM”插座。 | | 2 | 旋轉開關轉至ACV區域。（最大電壓勿超過 AC 750Vrms。） | | 3 | 將測試棒與待測線路並聯。 | | 4 | 從液晶顯示器讀取待測電壓值。 |
直流電流測試 DCA | 1 | 將紅色測試棒插入“mA”插座（大於200mA則插入10A插座），黑色測試棒插入“COM”插座。 | | 2 | 旋轉開關轉至DCA區域。（若不知道待測電流的約略值，則轉至最高檔，再依實際測量值轉至最佳解析度為止） | | 3 | 將測試棒與待測線路串連。 | | 4 | 從液晶顯示器讀取待測電流值。 |
電阻測試 OHM | 1 | 將紅色測試棒插入“V/Ω”插座，黑色測試棒插入“COM”插座。 | | 2 | 旋轉開關轉至OHM（Ω）區域。（若不知道待測電組的約略值，則轉至最高檔，再依實際測量值轉至最佳解析度為止） | | 3 | 將測試棒接到待測電阻上。 | | 4 | 從液晶顯示器讀取待測電阻值。 |
二極體測試 | 1 | 將紅色測試棒插入“V/Ω”插座，黑色測試棒插入“COM”插座。 | | 2 | 旋轉開關轉至二極體 “ ”檔位。 | | 3 | 將測試棒接至待測二極體。 | | 4 | 從液晶顯示器讀取測量值。 |
電晶體測試 | 1 | 旋轉開關轉至 hFE 區域。（依電晶體形式轉至 PNP 或 NPN 位置。） | | 2 | 將待測電晶體腳位 EB 配合插孔標示插入電晶體測試插座。 | | 3 | 從液晶顯示器讀取 hFE 值。 |
重點在 PS_ON# 這支接腳即16號接腳，只要跟任何 GND 的接腳(3、5、7、15 、17 、18、19)短路即可啟動ATX 電源供應器進行直流輸出(電源供應器的散熱風扇開始運轉)。要注意的是，短路動作要一直保持，一旦兩接腳開 路，ATX 電源供應器就會停止直流輸出(電源供應器的散熱風扇停止轉動)。
PS: 千萬不要以電線線色來做判別，各家電源供應器廠商的線色使用不盡相同！
這樣還不能保證電源供應器沒壞，只是知道電源供應器可啟動而已. 這只是最基本的功能沒壞. 接下來還要量各腳的輸出訊號(這只能大約得知各輸出是否正常)，然後再進行負載測試, 也就是接上主機板
======================
Method 1
DD-WRT serial recovery
======================
Method 2
TFTP recovery in Windows
- Get your router's MAC, its the 12 digit default SSID printed on the sticker at the back of the router, starting with 00. Then you'll need to break it down every two digit by inserting : or - between them.
- Download the latest official firmware(in case of recovery) from Buffalo's official website. Extract to get the firmware, in my case, its 1.74 and the firmware name is wzrhpg300nh-174, ~20MB.
Also download the Linksys TFTP utility.
- (May not necessary) Do a hard reset or 30/30/30 on the router.
- Unplug all the ethernet cable and the power cable and connect the computer directly to the router(still leave it off)
- Set the computer's static IP to 192.168.11.2, netmask 255.255.255.0, gateway/DNS 192.168.11.1.
- Open a Windows command prompt as Administrator. This is default on Windows XP, under Windows Vista/7, type cmd in the search box from Start menu, then press Ctrl+Shift+Enter. You will be prompted with the User Account Control dialog.
- Type route print to get a list of your NIC(s). Write down the interface number for the LAN card, in my case, it's 12.
- Now type the command below to get the ARP binding(thanks ermax at DD-WRT forum):
netsh interface ipv4 add neighbors 12 192.168.11.1 00-1d-12-34-56-78
Replacing the number 12 with the interface number and 00-1d-12-34-56-78 with the router's MAC address.
- Run Linksys TFTP utility. Put 192.168.11.1 as Server address, Password empty, File is wzrhpg300nh-174 just extracted, set retry time to 30.
- Click "Upgrade" in the TFTP utility and quickly plug the power back to turn on the router. There might be few failed attempts but the flash process should start later. Wait patiently the router will reboot itself when the upgrade is done. Navigate to http://192.168.11.1(for stock firmware) to configure your router.
TFTP recovery in Linux
*Most of this part is from DD-WRT wiki with some tweak. TEST WORKING
Will use Ubuntu Live CD as an example but other distro should also work. The Ubuntu LiveCD can be booted from a USB flash drive. See here.
- Do Step 1-4 in "TFTP recovery in Windows" except we don't need Linksys TFTP utility here. So we have MAC address ready, router unpowered and the computer is directly connected to the router.
- After booting into Ubuntu, open a terminal and type:
sudo apt-get update
sudo apt-get install tftp-hpa
sudo /etc/init.d/networking stop
sudo ifconfig eth0 192.168.11.2
sudo ifconfig eth0 netmask 255.255.255.0
sudo arp -s 192.168.11.1 00:1D:12:34:56:78#change to the folder where you put the firmware image, if it's on desktop then it's
#"/home/ubuntu/Desktop".
cd /home/ubuntu/Desktop
tftp 192.168.11.1
*from this point, you're under tftp command prompt, the "tftp>" is the prompt tftp gives you, you just need to type the command AFTER that.
tftp> verbose
tftp> binary
tftp> trace
tftp> rexmt 1
tftp> timeout 60
tftp> put wzrg300nh-firmware.tftp
Replace the fictional MAC in red with the router's. All command you need to input is in italic. Also replace wzrg300nh-firmware.tftp with the firmware you need, in case of stock firmware, its wzrhpg300nh-174.Also, at this point, the router is still unpowered and that's OK. Tftp will keep trying to send the firmware to the router and when it fails (because the router isn't yet on or hasn't yet brought up it's tftp interface) it will wait 1 second and retry, up to 60 times as that's how we set up the tftp client.
- Now quickly plug the power cord back to the router. The router will start up and you will see some lights blinking (possibly). About 10-20 seconds in, you should notice that tftp is sending the file. instead of the retry message over and over you will see some progress scrolling down the screen and at the end it will tell you how many blocks or bytes were transferred in how many second.
- After the transfer is complete, wait about 5-10 minutes the router will reboot itself. When the wireless LED is on you're good to go.
- Bring the network back in Linux by typing
sudo service networking start
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Reference 1. : " http://www.dd-wrt.com/wiki/index.php/Recover_from_a_bad_flash"
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