HARDWARE & NETWORKING

LED Calculator

2011-05-03T14:57:00.000+05:30

This LED calculator will calculate the current limiting resistor value and rounds the resistance to closest standard 5% resistor value.To use this software you need to enable Javascript in your browser.(works fine in IE7 and Firefox 3)

CLICK HERE

4 Band Resistor Color Code Calculator

2011-05-03T14:50:00.001+05:30

To use this software you need to enable Javascript in your browser.
(works fine in IE7 and Firefox 3) CLICK HERE

LM317 CALCULATOR

2011-05-03T14:45:00.000+05:30

CLICK HERE

Online ("True") UPS

2010-02-19T12:41:00.003+05:30

The online UPS, sometimes called a true UPS, is the best type you can buy. Paradoxically, it is both very similar to, and totally opposite to, the least-expensive type, the standby UPS. It is very similar to it in that it has the same two power sources, and a transfer switch that selects between them. It is the exact opposite from the standby UPS because it has reversed its sources: in the online UPS the primary power source is the UPS's battery, and utility power is the secondary power source!

Line-Interactive UPS

2010-02-19T12:37:00.003+05:30

The line-interactive UPS uses a totally different design than any type of standby UPS. In this type of unit, the separate battery charger, inverter and source selection switch have all been replaced by a combination inverter/converter, which both charges the battery and converts its energy to AC for the output as required. AC line power is still the primary power source, and the battery is the secondary. When the line power is operating, the inverter/converter charges the battery; when the power fails, it operates in reverse.
The main advantage of this design is that the inverter/converter unit is always connected to the output, powering the equipment. This design allows for faster response to a power failure than a standby UPS. The inverter/converter is also normally fitted with circuitry to filter out noise and spikes, and to regulate the power output, providing additional power during brownouts and curtailing output during surges.

The line-interactive UPS is an improved design that is commonly used in units for home and business use, available in sizes up to 3,000 VA or so. It is superior to the standby UPS, but it still has a transfer time, and thus does not provide protection as good as the online UPS.

Standby UPS / Standby Power Supply

2010-02-19T12:33:00.003+05:30

The standby UPS is the simplest and least expensive UPS design. In fact, some don't even consider a standby UPS to really be a UPS, calling it instead a standby power supply (SPS). However, many of the most common consumer-grade devices marketed as UPSes, particularly on the lower end of the budget scale, in fact use this general design. They are sometimes also called offline UPSes to distinguish them from online UPSes.

In this type of UPS, the primary power source is line power from the utility, and the secondary power source is the battery. It is called a standby UPS because the battery and inverter are normally not supplying power to the equipment. The battery charger is using line power to charge the battery, and the battery and inverter are waiting "on standby" until they are needed. When the AC power goes out, the transfer switch changes to the secondary power source. When line power is restored, the UPS switches back.

To delete partitions on a hard drive:

2009-12-25T14:42:00.004+05:30

Boot to Win98SE startup disk (It is the best OS made boot disk ever). Type in debug at the A: prompt.

Enter in the following commands:

Blue: what you type in.

Pink: what is displayed on the screen. (DO NOT TYPE THIS IN!)

Red: this is useful information. (DO NOT TYPE THIS IN!)
-----------------------------------------------------------------------------------------------
-----------------------------------------------------------------------------------------------
-F 220 L1000 0 (ENTER)
-A CS: 100 (ENTER)
xxxx:0100 MOV AX,301 (ENTER)
xxxx:0103 MOV BX,200 (ENTER)
xxxx:0106 MOV CX,1 (ENTER)
xxxx:0109 MOV DX,80 (ENTER) <---"80" for hd1, "81" for hd2 >
xxxx:010C INT 13 (ENTER)
xxxx:010E INT 20 (ENTER)
xxxx:0110 (ENTER) <-------BLANK LINE "VERY IMPORTANT" >
-G (ENTER)
Program terminated normally
- (CTRL)-(ALT)-(DEL) to reboot system

VISTA Activation Crack

2009-12-05T14:55:00.003+05:30

:-Download the above file "vista_sp1_hack"
:-Extract the files
:-now open extracted folder
:-Dobble click on "Vista Activation Crack"
:-This'll take few minutes
:-After than restart the pc and take effect.

Deep Freeze

2009-10-15T09:20:00.000+05:30

Understanding VPNs and the VPN Gateway

2009-05-21T09:47:00.000+05:30

Virtual private networks (VPNs) enable users to connect to a remote private network through the Internet. Virtual private networks therefore span the Internet because the user connects over the Internet to the remote VPN server. With a VPN, data is first encrypted and encapsulated before it is sent to the remote VPN server. When the VPN server obtains the data, it decrypts the packet so that is can be interpreted.

VPNs are usually implemented to provide for the following scenarios:
Enable remote access users to connect to and access the network.
Provide connectivity between two or multiple private networks or LANs.
A VPN gateway, also called a VPN router, is a connection point that connects two LANs which are connected by a nonsecure network such as the Internet. A VPN gateway therefore connects to either a single VPN gateway, or to multiple VPN gateways to extend the LAN. This scenario is typically referred to as a router-to-router VPN. The corporate networks are connected through the VPN servers running Routing And Remote Access (RRAS). The actual medium that connects the LANs is usually the Internet. This means that the VPN gateway or router will be configured with the address on the LAN that it is connected to, and a public IP address.

team viewer

2009-05-12T14:26:00.001+05:30

MONITOR SMPS

2009-02-20T10:27:00.011+05:30

MONITOR REPAIR LESSON

Troubleshooting a dead monitor

Checking the primary side

If the monitor is dead the first thing to do is to verify if there is voltage on the drain of the switching FET of the main power supply
In case there is not voltage, you have to seeking for some open thing like blown fuse, resistors or broken traces.
The normal voltage on its drain is about 150V when the monitor is plugged to a 120V AC outlet (USA users) or 300V when the monitor is hooked to a 220V AC outlet (UK users)

But if you check it and find voltage on its drain, it means that the rectification is good and the power supply unit is blocked for some reason

In this case, you must verify if there is start-up voltage on the main power supply
If the unit uses the IC 3842 or 3882 as shown below, the start-up voltage must be about 12V

For other ICs check its datasheet to find out which is its start-up pin

If the start-up voltage is not present, you must seek for blown start-up resistors
The start-up resistors are high resistance resistors such as 220K or 470K resistors

In many cases you find the start-up voltage, but the power supply does not work

In this case the problem can be:
1 - Short on the secondary side
2 - Short on the optical coupler or on some part hooked to it
3 - Short on some part in the primary side itself

Step for analysis of short on the secondary side
Remove or suck up the collector of the HOT.

If the power supply works, then it means that the power supply has no problem
In this case the problem is on the horizontal output: Fly-back, HOT or yoke.

In some monitors if you remove the HOT and do not apply a load resistor on its place, some capacitors will explode because the power supply may increase beyond its normal value. In other lessons you will see how to apply load resistors
If you don´t want apply a load resistor you must turn the monitor on only for a brief moment
If the main power supply won't work yet, maybe there's a short in any of the secondary lines

You can check that with the multimeter in the scale of ohms (100R)
For checking shorts, unplug the monitor from the AC outlet and check the resistance of each one of the sources of the secondary.

First put the red probe of the multimeter on the source and the black tip on the ground, then invert and put the black tip in the source

Check all of the sources of the secondary.
When you put the red tip in the cathode of a diode, it is normal to find low resistance.
However when inverting the tip you should find a higher resistance.

If you find the same resistance on both sides, there's a short on that source.
In the illustration above when the black tip is on the cathode and red tip is on the ground, the resistance should be higher.

Important: To measure the resistance of the source of the heater you must remove CRT PCB, because the CRT heater resistance is very low and it will show a false short. The heater is the lowest secondary power supply line
Never measure on the anode of the diode , measure on the cathode because the anode is hooked the a coil of the chopper which has low resistance and this coil has a terminal hooked to the GND. Therefore there will always be low resistance on the anodes that are hooked to the chopper.

If the short is in a medium power supply (between 20 and 35v), probably the cause can be a short in the vertical output.
In this case, if you don't know which pin is +B of the vertical IC, to remove the IC from the PCB and the short will disappear.
Replace the IC and the problem will be solved

If the short is on a higher source as 53 to 150v, probably this is the source of the horizontal output.
Then you must remove the HOT or to suck up the pin of the fly-back +B.

If the short is on the highest source (usually 150v) then it is probable that the short is in the RGB output.
There are monitors which use three RGB output transistors, others uses a power RGB IC.

A shorted RGB IC can also cause the main power supply to be dead because it's hooked directly to the power supply

If you found no problem on the secondary side, then you must check the primary side

In monitors that use 3842 IC on its power supply, check capacitors hooked to its pins # 3 and #4
Also replace small electrolytic capacitors as shown below:

It's recommended to replace the capacitors because many of them can pass the multimeter test and still be bad
At last, if the problem is not found, the optical coupler must be replaced

Below you can see two types of optical couplers

In lesson 5 we show how you can test an optical coupler and how does it work
You can choose between testing or replacing it without testing

That's all for a while

Creating and Configuring FTP Sites in Windows Server 2003

2008-12-03T13:50:00.002+05:30

Password Recovery Utilities

2008-10-03T11:10:00.002+05:30

Hack System Properties

2008-10-01T14:50:00.005+05:30

How To Make Xp Bootable Disc

2008-06-02T14:25:00.001+05:30

The following items are required:

A copy of the original Windows CD/DVD or ISO.

A copy of the Boot Files (Downloaded Below).

A minimum of 1GB available hard disk space for CD's.
A minimum of 5GB available hard disk space for DVD's.

How to unlock the password protected memory card of your mobile phone.

2008-05-28T16:00:00.000+05:30

have seen such a case when one my friend forgot the password of his memory card of his mobile phone and he have some very important data in the memory card which he want to recover, he tried almost everything then he lost hope and then asked the mobile phone company to find the way to recover the data from the memory card.

But you don’t worry if you are having the same problem…as now there is a much simple and easy way out.

Requirement: You need a file explorer like FExplorer which you can download from here.

How to Unlock MMC card:

Method 1:

Insert card into your phone but don’t access it through phone.
Run FExplorer and Open the path C:\system.
You will find a file called mmcstore ,rename the file mmcstore.txt
Copy that file(mmcstore.txt) to your pc and open that file in notepad.
You will find your password in that file.

Laptop Repairing

2008-04-26T10:29:00.005+05:30

Five Stages of Mastering the Windows Registry

2008-04-15T16:02:00.001+05:30

1. Fear of the new language
Mastering the registry, means learning a new language with its own syntax. At first there seems to be no pattern just strange words and hexadecimal numbers. For example, HKEY_Local_Machine Dword 0x00004B.

Activities in this first stage are confined to tentatively changing a few values from zero to one.

2. Wonderment Power Skill
After a while you begin to crack the code, HKEY_Current_User means the personal settings of the account logged on. It hits you that a String Value is text and DWORD is a number.

As you advance from changing existing values to adding new values you realize that the words are not case sensitive and the mixed case is just to make 'Values' easier to read.

3. Complacency - I can do anything
Now you reach the stage where a little knowledge is dangerous, you discover export and realize that you can import settings quickly by double clicking .reg files. Because you are having such fun you start taking risks, you cannot imagine anything can go wrong.

4. Panic - slip on a banana skin
Complacency will inevitably lead to disaster. Just as surely as children playing with knives get cut, or those playing with matches get burnt, so those messing with the registry will get: Machine will not boot Stop 0x0000051 error.

Stop messages like the above cause the heart to beat faster, you realize that you have gone too far and deleted or overwritten a vital section. At this stage it is either do or die. Either you vow never to touch Regedit again, and rebuild the machine from scratch, or you stay calm and rise to the next skill level.

5. Respect for registry editingKnowledge, power, and respect go hand in hand. In times of crisis you remember good practices, firstly you try F8, and Last Known Good. If that does not work then there is safe mode.

Once safe mode gets you in then you have a variety of tactics. Best is probably to restore the registry from the system state backup you made just before your Regedit session. You did backup didn't you?

If that does not work then boot into a parallel installation (if you have one). If there is no time for a parallel installation try and get a command console session started. Either run winnt32 / cmdcons in advance of your Regedit changes, or put a bootable OS CD in the caddy, and select Restore from the menu.

The .sav files could be your salvation I once used a parallel installation to find the original %SystemRoot%\System32\config folder and renamed software.sav and so got the machine to restart. Once the machine started I was able to import a .reg file that I can cunningly exported before trying a risky experiment.

In this final stage, you always have an eye on safety. Make those backups, assemble those tools, export the registry section regularly.

registry

2008-04-15T15:43:00.000+05:30

Hives
The Registry is split into a number of logical sections, or "hives".[3] Hives are generally named by their Windows API definitions, which all begin "HKEY". They are abbreviated to a three- or four-letter short name starting with "HK" (e.g. HKCU and HKLM).

The HKEY_LOCAL_MACHINE and HKEY_CURRENT_USER nodes have a similar structure to each other; applications typically look up their settings by first checking for them in "HKEY_CURRENT_USER\Software\Vendor's name\Application's name\Version\Setting name", and if the setting is not found look instead in the same location under the HKEY_LOCAL_MACHINE key. When writing settings back, the reverse approach is used — HKEY_LOCAL_MACHINE is written first, but if that cannot be written to (which is usually the case if the logged-in user is not an administrator), the setting is stored in HKEY_CURRENT_USER instead.

HKEY_CLASSES_ROOT (HKCR)
Abbreviated HKCR, HKEY_CLASSES_ROOT stores information about registered applications, such as file associations and OLE Object Class IDs tying them to the applications used to handle these items. On Windows 2000 and above, HKCR is a compilation of HKCU\Software\Classes and HKLM\Software\Classes. If a given value exists in both of the subkeys above, the one in HKCU\Software\Classes is used.[4]

HKEY_CURRENT_USER (HKCU)
Abbreviated HKCU, HKEY_CURRENT_USER stores settings that are specific to the currently logged-in user. The HKCU key is a link to the subkey of HKEY_USERS that corresponds to the user; the same information is reflected in both locations. On Windows-NT based systems, each user's settings are stored in their own files called NTUSER.DAT and USRCLASS.DAT inside their own Documents and Settings subfolder (or the Users subfolder in Windows Vista).

HKEY_LOCAL_MACHINE (HKLM)
Abbreviated HKLM, HKEY_LOCAL_MACHINE stores settings that are general to all users on the computer. On NT-based versions of Windows, HKLM contains four subkeys, SAM, SECURITY, SOFTWARE and SYSTEM, that are found within their respective files located in the %SystemRoot%\System32\Config folder. A fifth subkey, HARDWARE, is volatile and is created dynamically, and as such is not stored in a file. Information about system hardware drivers and services are located under the SYSTEM subkey, while the SOFTWARE subkey contains software and Windows settings.

HKEY_USERS (HKU)
Abbreviated HKU, HKEY_USERS contains subkeys corresponding to the HKEY_CURRENT_USER keys for each user profile actively loaded on the machine, though user hives are usually only loaded for currently logged-in users.

HKEY_CURRENT_CONFIG
Abbreviated HKCC, HKEY_CURRENT_CONFIG contains information gathered at runtime; information stored in this key is not permanently stored on disk, but rather regenerated at boot time.

HKEY_PERFORMANCE_DATA
This key provides runtime information into performance data provided by either the NT kernel itself or other programs that provide performance data. This key is not displayed in the Registry Editor, but it is visible through the registry functions in the Windows API.

HKEY_DYN_DATA
This key is used only on Windows 95, Windows 98 and Windows Me. [5] It contains information about hardware devices, including Plug-and-Play and network performance statistics. The information in this hive is also not stored on the hard drive. The Plug and Play information is gathered and configured at startup and is stored in memory. [6]

Keyboard Shortcuts

2008-03-08T15:47:00.000+05:30

CTRL+C
Copy.
CTRL+X
Cut.
CTRL+V
Paste.
CTRL+Z
Undo.
DELETE
Delete.
SHIFT+DELETE
Delete selected item permanently without placing the item in the Recycle Bin.
CTRL while dragging an item
Copy selected item.
CTRL+SHIFT while dragging an item
Create shortcut to selected item.
F2
Rename selected item.
CTRL+RIGHT ARROW
Move the insertion point to the beginning of the next word.
CTRL+LEFT ARROW
Move the insertion point to the beginning of the previous word.
CTRL+DOWN ARROW
Move the insertion point to the beginning of the next paragraph.
CTRL+UP ARROW
Move the insertion point to the beginning of the previous paragraph.
CTRL+SHIFT with any of the arrow keys
Highlight a block of text.
SHIFT with any of the arrow keys
Select more than one item in a window or on the desktop, or select text within a document.
CTRL+A
Select all.
F3
Search for a file or folder.
ALT+ENTER
View properties for the selected item.
ALT+F4
Close the active item, or quit the active program.
ALT+Enter
Displays the properties of the selected object.
ALT+SPACEBAR
Opens the shortcut menu for the active window.
CTRL+F4
Close the active document in programs that allow you to have multiple documents open simultaneously.
ALT+TAB
Switch between open items.
ALT+ESC
Cycle through items in the order they were opened.
F6
Cycle through screen elements in a window or on the desktop.
F4
Display the Address bar list in My Computer or Windows Explorer.
SHIFT+F10
Display the shortcut menu for the selected item.
ALT+SPACEBAR
Display the System menu for the active window.
CTRL+ESC
Display the Start menu.
ALT+Underlined letter in a menu name
Display the corresponding menu.
Underlined letter in a command name on an open menu
Carry out the corresponding command.
F10
Activate the menu bar in the active program.
RIGHT ARROW
Open the next menu to the right, or open a submenu.
LEFT ARROW
Open the next menu to the left, or close a submenu.
F5
Refresh the active window.
BACKSPACE
View the folder one level up in My Computer or Windows Explorer.
ESC
Cancel the current task.
SHIFT when you insert a CD into the CD-ROM drive
Prevent the CD from automatically playing.