Repairing a TOSHIBA LCD TV 19W331DG

A customer brought to me a TOSHIBA LCD TV, model 19W331DG, with some strange problems.

For example, sometimes after turning it on the backlights didn’t light on.
I immediately found the problem: on the power board there where two blown capacitors, one was a high capacity value, like 25V 1000uF, and it was clearly visible. The other, was a 50V 220uF that I found as defective just after measuring the ESR value. Externally it seemed ok.

So, after replacing these two capacitors, the TV worked perfectly.

But another problem came out.

After something like 2 hours working, the backlights turned out again. This time wasn’t a capacitor problem, and everything looked ok.
So, what could stop working after 2 hours, and why?

TOSHIBA TV LCD 19W331DG power board repair
TOSHIBA TV LCD 19W331DG power board repair


Note the heat skins added to main the power regulator, the main power diode and the main transistor.

Simply, the semiconductors regulating the backlights main power shut down after overheating.

Bye!

Searching inside a lot of files in Linux

Hi all,
how many times you Linux newbies needed to search inside a lot of files, looking for a specified string?

This task is really useful, specially when debugging websites and php scripts.

So, this is the command you need:


find . | xargs grep 'string to search'

Let’s look at how it works:

find – it returns the name of files found inside the given directory, recursively looking inside sub-directories, one name per line.

grep – it strips a line of a given input and returns it when result matches

xargs – executes a command, passing to it the arguments read from the standard input.

Bye!

Create a TAR archive of a directory

A common task in unix-like operating systems is creating an archive of many files or directories in a single file. The tar command is one option for archiving and has many options and can do many things.

In a simple example, you can create a file called archive.tar of all the files and subdirectories in the current directory with the following command:

tar cf archive.tar *

Note that this file is different from a zip archive commonly used in Windows environments because it is uncompressed.

You can also preserve permissions, owner and group by adding the p parameter.

betaBSD vs OpenBSD

Finalmente si notano i primi risultati del lavoro sul sistema betaBSD…

Il lavoro è ancora molto lungo e per ora l’unico risultato reale è una strana somiglianza tra il nostro rack e quello del sito ufficiale di OpenBSD 😀

La cosa è casuale e appena l’ho notata ho fatto una foto…

 

OpenBSD Server Rack (2009)
OpenBSD Server Rack (2009)
betaBSD Server Rack (now)
betaBSD Server Rack (now)

 

Per chi non conoscesse betaBSD, rimando al sito su sourceforge http://sourceforge.net/p/betabsd, attualmente l’unica pagina ufficiale anche se incompleta, che a breve sarà sostituita da un sito dedicato con hosting su betatechnologies.it