Wednesday, 16 February 2011

Moving blog to wordpress




The end of an era... The start of a saga...
I'm moving this blog to my fancy new domain name GeekGreek.com
This blog will remain active but the comments are locked and all posts from now on will link to the new shiny wordpress blog.*
If you want to comment, you will have to do it on the new blog with a wordpress account. Don't forget to update your bookmarks people!
Bye bye and thanks for all the fish.

*Many thanks to arunmvishnu for the redirecting script.

Monday, 6 December 2010

Replace the screen on the EEE PC 901




What do you do when electronics fall apart? Most of us just bin it and buy a new one. Especially with the high prices the I.T companies charge. 50 euros just to look at it? F that. There's another way: D.I.Y.
It's really not that difficult. Here's how to replace a broken LCD on the EEE PC 901.



The above atrocity happened when a cell phone went flying and landed flat on the screen. The netbook didn't sustain any other damage. It just needs an LCD change.
First step is to locate the necessary replacement part. The 8.9" LCD screen. They sell for just 42 euros (£36) on ebay. Thank god for the Chinese!



Here's the old and new screen side by side.
Next, make sure that you have a screwdriver, and an old credit card or a guitar pick. If your screwdriver isn't magnetized you can attach a magnet on it. It helps a lot in removing the screws without losing them.



Start by removing the charger and the battery. Then remove 7 screws on the bottom. Because I tend to forget where each screw goes so I try to group them together with magnets and write down a short description to help me with the re-assembly. I strongly recommend you to do the same.



Now in order to remove the keyboard you have to press 3 tabs that hold it in place.



Here's a close-up of one of the tabs



After you free the keyboard from the tabs lift it slowly from the top. The lower part is attached to the rest of the netbook via the connecting ribbon. In order to disconnect it you have to pry apart the little black piece of plastic that keeps the ribbon tight in place. Then the keyboard is free. Put it aside.


this is the point of no return. If you're having second thoughts this is the time to screw everything back because after you break that yellow sticker you instantly void your warranty. Of course if your warranty is already expired, you got nothing to fear.



unscrew everything you see, and detach the little touchpad cable. It has the same locking mechanism as the keyboard.



Now for the next step, you have to insert something soft and slim on the sides to separate the top from the bottom. DO NOT use a screwdriver or you will scratch and mark the plastic. Use an old credit card, or a guitar pick.



Ta-daaa! Sexy exposed electronics. Notice the thermal paste on the CPU, GPU and north-bridge. The upper chassis functions as a heatsink that dissipates heat through the keyboard. Optionally, Remove the LCD ribbon on the right.



Next, you have to remove the plastic tabs that hide the screws. Keep them somewhere safe to put them back once we're finished. After you unscrew the 6 screws that hold together the monitor. Now in order to pry the LCD casing appart you need your trusty guitar pick or credit card. Insert, and pry away.



Remove the cable on the back of the LCD.



Next remove the support brackets and keep them for the new LCD. Throw away the old LCD. (By "throw-away" I really mean recycle). Screw back the support brackets, connect the LCD ribbon, and test that it's working before you re-assemble everything.



It's alive!!





Final step: remove the protective film. Congrats. You made it.

Sunday, 10 October 2010

DIY Lab Bench PSU

My old Bench PSU had died and I needed a new one for my water-gun project (Work in progress), so it was a good time to document the process as well for the benefit of others.

List of materials.
  • A discarded computer Power Supply Unit. (PSU)
  • At least 2 terminals
  • 2-state flip switches
  • A 12v fan
  • an on-off rocker switch
  • Dremel
  • LCD Voltage meter (Optional)
  • Sandpaper & Paint (Optional)
My Donor PSU has a large 120mm fan on top of it that is not very useful. It takes up all the space. It had to go. As a replacement I used the top off another PSU with no top fan. The dimensions are the same anyway.



First step is to open it up as see what we got. Some dust bunnies, and a lot of dirt. I vacuumed it and then cleaned it carefully with an old toothbrush. Bellow you can also see the 110v-220v switch. I never plan to use it on 110v so I removed it.





Next step is to figure out the layout of all the switches, fans, etc. I drew the outlines as a guide for the dremel.



I used the carbon fiber bit for the straight cuts and the metal drill bits for the holes. It took me hours to finish it.



I then sanded it and gave it a bright white finish. I then cut all the excess cable, but left a power molex intact to use it as a PC components tester.



This is the main on-off switch. Cut-off the main motherboard power molex, and connect the green and the black to the switch so that when you flick the switch, the circuit closes and the PSU thinks that the motherboard is on. When soldering, I recommend you use a "handy tool" for holding the cables. It's very handy.



My new revised design uses just 2 terminals, and 4 flip-switches as voltage selectors. This way when you want to change voltage you don't have to connect and disconnect to various terminals. You can also see the LCD voltage-meter bellow. I used hot glue to fix everything in place. It doesn't look very good on the inside, but looks flawless on the outside.



I glued rare-earth neodymium magnets to store the test-molex on the side of the case. This way it's out of the way and at hand when needed.

 

Here is the final result. I love the black and white theme. Reminds me of stormtroopers.



For the final touch I added some labels with a sharpie. Available voltages are 3.3V, 5V, 8.3V, 10V, 12V, and 17V.

Monday, 6 September 2010

How to fix a dead fuel pump on the Aprilia Pegaso Strada



This is how it all went down:
In the 3 years that I lived happily with my bike, only 2 times it refused to start. I presumed it was due to the cold, affecting the battery. After a couple of days the problem disappeared on it's own, and the bike started again in both cases.
I visited an authorised Aprilia service where I was told that it's the fuel pump that it's starting to fail.
To add to my dismay, Aprilia doesn't sell just the fuel pump as a replacement part, but the whole assembly including the fuel gauge sensor, and the fuel filter. How much does it cost you ask? £433 (519 euros) !!!



And this is just the cost of the part. You also have to add the cost of labour to disassemble half the bike to reach inside the tank.
So I postponed it. The mechanic told me that a well-placed punch on the left side of the tank where the fuel pump is located, will make it run again. And so I did. Every time the bike refused to start, I would punch it once, and it would always start. On some rare occasions I had to punch 3 or 4 times, but the trick would always work. And so 1 year passed, and I got used to all the punching.
Until it stopped working completely. No matter how hard I slapped the tank, the engine wouldn't start. After 38.800km of The fuel pump went from living-dead to just dead.

It was about time to hack it. There's no way I would pay 500+ euros for a fuel pump that allegedly has the tendency to fail again and again, each time setting you back 500 euros.
Fortunately many people around the world suffer from the same problem, and thanks to the power of internet they share some of their knowledge and lessons taught. In this case google is our friend. I found invaluable help in the ApriliaBikers.gr forum, and the ApriliaForum.com.

The main idea is that instead of buying the whole assembly from aprilia, you replace just the faulty pump with a car fuel pump. The problem is that there is no fuel pump on the market small enough to fit in the place of the original one so you have to be creative. Generally any pump will do as long as it's 12v and has a rated pressure above 3.2 bar. So I went out there and asked around at the car-parts shops. Some were persistent to know the make and model of the car it's going in, and as soon as I said the word motorcycle they wouldn't listen any more. In the end I found a helpful shop owner who gave me a Siemens 3.8 bar pump that looked small enough. Cost: 60 euros.
Then I searched for a suitable in-tank fuel filter. According to the good people of the aforementioned forums, the Mann MWK-44 is a perfect replacement. It's better build than the original Aprilia, and even cheaper: 48 euros for the aprilia, and just 22 for the Mann.

If you want to buy the same pump as me you might want to use the markings on the box:

It reads 993-784-025X Kraftstoffpumpe HPi8

Before you start the operation make sure you've got all the ingredients:
  •  3.8 Bar 12v Fuel Pump
  • Mann MWK-44 Fuel Filter
  • 50cm of hose
  • 4 hose clamps
  • Hex keys collection
  • Screwdriver
  • 7mm Wrench / spanner



My brother demonstrating  the items of the utmost importance. A new pump and a cup of coffee. (The Greek frappe kind).
It's very handy to have a brother to help you. Couldn't have done it without him. Thanks bro!

In order to get to the fuel pump you need to remove the tank. In order to get to the tank you need to remove the headlight and the glove-box compartment. Here we go: Start unscrewing!


Unscrew 6 screws to separate the dash from the headlight.


Unscrew the supporting bracket, and disconnect the cabling from the bracket.


The head of the beast.


Unscrew the glove-box but leave the latch mechanism as is. It doesn't bother us.

With the glove-box and the 2 side-covers removed, lifting the tank is pretty straight forward. Just make sure to unscrew the central bolt under the glove-box and 2 on the side. I'm sorry for the lack of photos but we got carried-away on this point.



The striped-down bike, and my bro complaining about the low level of coffee.


This is where the fuel pump assembly came from


The golden part in there is the original faulty pump. It will be replaced by the brand new siemens on the right.


The original and the replacement side by side


There's no way it will fit without some "modifications"


I had to "surgically" remove all of the pump holder (Click to enlarge)


The final result. Beautiful.


In my case the DC connectors where slightly different so I had to solder some new ones.


Done.


This is the complete assembly before I dip it back into the tank



Put it back there.
Re-assemble, and hopefully it will run.
Once you turn the key and before you hit the ignition, you should hear the pump working.
In my case I could hear the pump working, but once I hit the ignition it wouldn't start.
Turns out I had soldered the terminals the wrong way and the pump worked all right, but instead of pumping fuel into the engine it would suck it out. We removed it once again, soldered positive to positive and ground to ground, put it back in, and it started at once!!
Major success!!
Total cost of the project 89 euros. I saved about 430 euros