HDMI Extender: Solution to HDMI Transmission over Long Cables By Jeff Su

Background:

The main advantages of HDMI, high definition multimedia interface, over standard analog video transmission is that it is 100 % digital from source to display. However, transmitting HDMI over long distances is not so easy. In this article we will describe some of the issues encountered during HDMI transmission and present a solution that can significantly improve HDMI transmission: the HDMI Extender. Continue reading “HDMI Extender: Solution to HDMI Transmission over Long Cables By Jeff Su”

Sea-Front or Action-gate By Richard Myers

Seagate Technologies’ web site now indicates the company offers data recovery services. Further investigation shows the shipping address, the place to send your subject drive for data recovery service, actually belongs to ActionFront Data Recovery. Many may already be aware of this little tidbit, to others it may be a surprise.

When asked about their arrangement Seagate?s Mike Hall responded, “The services are in trials with a limited number of customers at this time so, as with any other Seagate beta program, there’s little we can share about them other than what appears on our web site.” ActionFront’s Ron Austin responded with a simple, “No comment”. So much for gathering facts. Continue reading “Sea-Front or Action-gate By Richard Myers”

Drive Crashes

If your drive fails do not give the drive to someone whom has had no prior experience of recovery. This is a fate worse than death. Drive recovery MUST be performed by someone whom knows the mechanics involved. If you are old enough to remember the old cassette decks from years back you will remember the horrific effects of “wow and flutter” caused in mechanically unstable decks, more often than not caused by a pinch roller or capstan motor.  There is just no room for error in a hard drive – people boast of old gyro compass rotors spinning at 7200 rpm for a year without the need for servicing – think of a hard drive at a fraction of the price doing exactly the same. A hard drive is not designed for servicing – manufacturers rebuild the drive from scratch but in  reality the owner gets a brand new drive. Would you trust a hard drive which has only had the faulty part replaced – neither do the manufacturers. Continue reading “Drive Crashes”

Testing a Transformer- How To Accurately Test A Transformer By Jestine Yong

A transformer consists of two or more coils wound on the same core. For power transformers, the core material is usually iron. For a radio-frequency transformer, the core material is usually ferrite or air. The basic property of a transformer is to change AC voltage. A transformer cannot change direct current voltage. A step down transformer has a lower AC output voltage at its secondary winding than the AC input voltage to its primary winding. Conversely, a step up transformer has a higher secondary than primary voltage. The transformer laminations or coating of shellac, enamel or varnish is to insulate adjacent turns from shorts between winding. I will not go too details about how transformer work and transformer calculation as you can read more details from most electrical and electronic transformers books. Continue reading “Testing a Transformer- How To Accurately Test A Transformer By Jestine Yong”

The Importance Of Current Sense Resistor In Switch Mode Power Supply By Jestine Yong

In monitor power supply where pulse width modulation (pwm) ic UC3842 are used. Pin 3 of this power ic is called I-sense which means current sense and this pin is connected to source pin of POWER FET. The purpose of this current sense circuit is for overcurrent protection. This circuit usually samples the voltage drop across a resistor in series with the switching fet transistor. If the current rises abnormally due to some short circuit in the secondary side such as a shorted secondary diode or horizontal output transistor (HOT), the voltage will exceed a reference level and shutdown the pulse generator which is the PWM ic. This circuit provides protection to components in the event a problem occurs. In some cases where overload happen-the power section will blow and most of the time the components changed are fuse, power fet, pwm ic, zener diode and current sense resistor. Continue reading “The Importance Of Current Sense Resistor In Switch Mode Power Supply By Jestine Yong”