Computer hardware abbreviation list

 Starting new job - teaching those young people something about how computers work. In hardware level. This semester will be tough - will have to understand and simultaneously organise the course. 

Moodle, of course, as a platform where to put all tasks, activities, tests, materials. Since university is still setting all of that up for me, had to save one of the activities somewhere. And - why not to share.

So here it is - computer hardware abbreviation list - task to give to studens so they find the definitions of abbreviations so often seen around.

And here the same task in latvian. 

555 timer examples in falstad circuits

Few 555 timer chip examples built digitally in falstad circuit builder.

This one is Schmitt trigger with 2/3 and 1/3 Vcc hysteresis.
Check out extra sliders and see how current through led changes.

Simulation is here - http://tinyurl.com/y4rnjs4o


Another one - LDR logic board. Similar, but without hysteresis as threshold pin is connected to stationary 10k resistor, so the output is passed on at strict threshold level chosen by adjusting the variable resistor.

And the simulation - http://tinyurl.com/y6l7blt2


Here is a monostable circuit. Use switch as a push button and the LED will stay turned on for a certain time.

http://tinyurl.com/y6o47oxw

Repairing Samsung SyncMaster 920N

I bought this monitor around six months ago. It was slightly used, with even some scratches on the screen but as I used this monitor as second one it doesnt bother me very much. 

This morning I woke up, switched on both monitors and this one didnt want to light up. That means - Its power light responded and computer recognized it but no backlight working. 

Four screws for stand, two more in both lower corners.

I knew exactly what happened with it because I had exactly the same issue with the primary monitor which is same brand and model. There are two bad capacitors on that board which were gone boom. I decided to change them by myself. 

Previously in the primary monitor there were both capacitors and one MOSFET fried. That time I changed whole power board because of this fried MOSFET. 

First assumptions were that only these two capacitors were bad so I decided to change only them. But after changing them the monitor still didnt work and I saw that MOSFET frying with smoke. 

That observation killed all my hopes for repairing that circuit board by myself. Firstly I didnt have such MOSFET available and secondly, if I would have it, I wouldnt be able to solder it because not having proper instruments. 

Somehow I noticed that on this power board there are two identical MOSFETs. As I had saved this old power board from first monitor repairs, I thought - I could loose nothing if I would try to desolder off the one which wasnt fried from that old power board and change with that fried chip on the original power board of this second monitor. Well.. doing it carefully as much as I could, I got that monitor working again! So, I have skill up in soldering small things :D Here are some insights of how this monitor looks from inside.

See more pictures --->

Canoscan 8400f error 2 178 0

Bad FAU (film adapter unit) cable.
The scanner worked fine while scanning some documents and stuff. When I tried to scan some diapositive films, i got an error 2 178 0. In some forums people say it is because of cable. Tried to find some schemes, but unsuccessfully. Got another, working cable and additionally I made the scheme of the cable.

In my case the wires 8 and 9 was broken. The interesting part was that it was possible to avoid the error by putting the FAU in the start position manually by hand. When I launched preview, the error was gone and i got a preview of my diapositive. And then it stuck in the end - servo motor didn`t put the FAU in the start position. I realized that something is wrong with 1)electronics or 2)cable. With other cable scanner worked fine, so it is not electronics. And here it is - the wire 8 which eventually was broken is FAU (go) HOME. But still I have another wire - 9, which is FAU (gives) POWER. Could it be that FAU doesn`t get the power from it and takes power from wire 10? It seems possible, because I got it working with broken cable when I manually put the FAU in start position. The lamp was shining and the unit worked ... till it had to "go home" :D

sound problems

If sound is not working...

sudo alsa force-reload

worked for me and my Karmic

last night`s movie

fucking awesome movie!
no politics, no anti-military.
damn good and scary.
sometimes kicked shit out of me...

hibernating vs heavy processor load

Windows 7 bug: This night I didnt turned off the computer because of video rendering hoping that it will not shutdown while processing this video.
Waking up this morning i found my computer turned off. Firstly i thought it`s becouse of overheating (yesterday i changed lubricant between heat sinks and processor), but.. windows 7 was gone in hibernate mode by itself, ignoring video rendering. Firstly it was sooo slow.. Maybe to get working all things in virtual memory. But in 5 minutes all went fine.
So the question - is it good, that going to hibernate mode, OS is ignoring background processes, which has heavy processor load.

Dell Latitude d800 and Inspiron 8600

It is so simple to repair these kinda notebooks. All parts are like plug`n`play. And so easy and simple changing them. Even replacing the motherboard seems so simple.

But there`s one bad thing - screws are in different length. And that makes a problem remembering in which part should I use one or another screw length.

next level? fixing notebooks... hahah!