Chad Don Cooper Projects and ponderings…

9Jan/160

Making a decent cappuccino

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So I've had a DeLonghi ECC 221.B espresso machine for around a year now, I've used it constantly but never been quite sure how to get the most of it. The machine itself was somewhat of a bargain, I picked it up for £35 down from £125 when a local Tesco Extra was closing it's doors. Even with a price tag of £125 the machine is firmly considered budget to your average home espresso connoisseur, however I believe being a pump driven unit it's hard to beat without spending several hundred more.

So over the last week I've studied up and tried out a number of alterations to both the machine and the way I make a cup of coffee. The change in appearance, texture and taste of my cappuccinos has improved significantly, so much so I've written up how to achieve it below.

  • Buy fresh beans! I've been getting mine from Has Bean, they post them to you on the day they are roasted
  • Grind the coffee as fine as possible. Using one of my favourite presents ever, a Krups Expert GVX231 grinder, I was able to get some really good grinding results out of the box. Over the last week, I've been able to get it working even better by opening it up and adjusting the burr mechanism until grounds were coming out with a flour like consistency which is exactly what's needed for espresso with a good crema
  • Tamper the coffee. Using a good tamper is essential. For the DeLonghi a 51mm tamper is ideal, I purchased this one from Amazon. Getting the tamper right is all about finding the ideal pressure and twisting as you lift. The grounds should be pushed down leaving an even gap at the top of the basket
  • De-pressurise the basket. By default the basket it pressurised, put simply there is a spring loaded valve to keep the pressure high enough when using store brought pre-ground coffee. This is great for your average consumer because they get OK results from all types of coffee, but for me I want to use grounds that have completely pulverised and use tampering to control the pressure. De-pressurising the basket is pretty simple (and reversible), a video guide can be found here
  • Remove the plastic bottom from portafilter. You can either remove the bottom or drill a single large hole, although this is non-reversible
  • Steaming the milk. Using a decent amount of cold milk in a small cold stainless steel jug, insert the frother at a 45degree angle into the milk so that it begins to move in a circular fashion. Remove the frother when the temperature reaches 130 degrees (a temperature probe will aid with this)

Next on my list is bean roasting 🙂

Filed under: Tweaks No Comments
7Jan/160

VS2015 DNVM bug

In trying to run all the fancy new open source .net framework stuff I discovered a bug in the DNVM script which is included with the automatically downloaded RC1 version included with Visual Studio 2015. As documented here it's been noted to only affect users with a space in their username.

Running the self update commands in dnvm didn't fix the issue and I had to resort to manually swapping the files in "C:\Program Files\Microsoft DNX\Dnvm" with the latest from the github repo at https://github.com/aspnet/dnvm/tree/dev/src

Filed under: Fixes No Comments
7Jan/160

Unbricking my Acer C720 Chromebook

Almost inevitability through all my tinkering with my Chromebook, whilst I was trying to install Windows via a modified ROM, I managed to brick it.

Luckily like with any other bad BIOS flash the situation can be reversed by directly flashing the chip. To do so I used a Raspberry Pi with the SPI interface enabled along with an SOIC clip. There are other methods but this is by far the fastest and the most cost effective solution.

SPI can be enabled in Raspbian by running sudo raspi-config, selecting option 9, followed by A5. A reboot is then required for the module to be loaded by default. A quick check after reboot with lsmod | grep spi_ should show
“spi_bcm2708″ or “spi_bcm2835” listed in the output.

Wiring up the Pi is made easier with the help of my favourite pinout diagram which can be found here: http://riscpi.co.uk/definitive-raspberry-pi-pinout/ Pin 1 of the chip can be ID'd by looking for a dot by the pin.

Chip -> Pi
1 -> CE0
2 -> MISO
3 -> 3.3v
4 -> GND
5 -> MOSI
6 -> SLCK
7 -> 3.3v
8 -> 3.3v

I've not given the specific pin# so you look at the diagram and don't do something silly like put 5v through the chip causing it to fry!
Flashing
Install flashrom:
sudo apt-get install build-essential pciutils usbutils libpci-dev libusb-dev libftdi1 libftdi-dev zlib1g-dev subversion libusb-1.0-0-dev
svn co https://code.coreboot.org/svn/flashrom/trunk flashrom
cd flashrom
make
wget https://dl.dropboxusercontent.com/u/59964215/chromebook/ROM/coreboot-seabios-peppy-20151128-coolstar-celeron.rom
./flashrom -w coreboot-seabios-peppy-20151128-coolstar-celeron.rom -VVV -p linux_spi:dev=/dev/spidev0.0

The process takes a minute or two, don't be alarmed by the lack of feedback, once it's found the chip it's usually working
Flash OK

Filed under: Fixes No Comments
4Jan/160

Huawei G510 digitiser replacement

Nice easy one to fix, digitiser was also a barginlious £8. Removed some screws, clean the broken glass, add some new double sided 3M tape and put the glass in place. Can be done in half an hour.

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25Nov/140

HD-DVD disc rot

Turns out it was a good thing Blu-ray won the HD war after all, since a good chunk of the movies I own on HD-DVD are no longer working. Despite having no visible scratches or marks, a high percentage of discs, mostly Warner Brothers releases, have suffered disc rot. I'm about halfway through ripping my collection, the picture shows a working pile (left) versus a non working pile.

Working vs non-working HD-DVDs

Filed under: Problems No Comments
4Jan/140

Faulty Optoma EW533ST

I've had a faulty Optoma EW533ST kicking around for sometime now. It has a common fault with the DLP (DMD) chip which manifests itself as lots of white and black dead pixels.
The projector itself is actually an Optoma GT720, a fairly well respected 720p projector, which comes highly recommended for gaming, as stated in this review.
Specs:

  • Display Technology Single 0.56" WXGA DC3 DMD chip DLP® Technology by Texas Instruments
  • Resolution Native WXGA 1280 x 800
  • Brightness 2500 ANSI Lumens
  • Contrast 3000:1
  • Noise Level 27/29dB (STD/BRIGHT mode)
  • Aspect Ratio 16:10 Native, 4:3/16:9 Compatible
  • I/O Connectors Inputs: PC/Video: HDMI, 15 Pin D-sub (RGB/YPbPr/Wireless), S-Video, Composite, Audio In - RCA
  • The lamp life is quoted as high as 5000hrs!

All in all, worth saving in my opinion. To avoid ordering the wrong DMD chip I proceeded to strip down the projector and remove the DMD chip to get the part number, which turned out to be 1280-6038b. Reading showed that the 1280-6038b and 1280-6039b are both interchangeable, along with some other models. Further to this a newer model, the 1280-6338B, was released which apparently addresses the dead pixel issue.

The chip I have purchased can be found here: http://www.aliexpress.com/item/100-New-DMD-new-version-1280-6338B-replace-1280-6038B/898295952.html.

Filed under: Problems, Repairs No Comments
28Jun/120

iPod 4G screen replacement

Had to replace a smashed iPod 4G screen the last week. While it honestly wasn't all that hard, there were a few things I noted as being painful.

Firstly tools, without them you can't get very far. Make sure you have both a small and a large plastic pry tool. A metal "spudger" also makes installing the screen's data and back-light cable a much more pleasant process. A small Phillips screwdriver and a hairdryer are also needed.

Secondly be sure to remove all the glue and glass fragments from the old screen as they will stop the new screen from sitting flush - the Chinese replacement glass is already slightly thicker. It may even be worth avoiding 3rd party replacement screens and digitizers altogether (they're combined, don't buy a digitizer without the LCD, the amount of extra effort isn't worth the few $ difference). I've found putting pressure on a 3rd party screen results in LCD distortion occurring more often than with the original, it depends on how fussy/careful you are.

Lastly, watch out when seating the new screen. Make sure to fold the data cable in on itself, otherwise you won't get the screen to sit flush with the case. Transferring the home button is usually essential, the metal clip however is not. Personally I chose to transfer the clip and I also bought some pre-cut 3M double sided tape to hold the top and bottom of the new screen.

Filed under: Repairs No Comments
16May/120

Noisy Wii

I've observed the DVD drive being quite noisy on my Nintendo Wii ever since I bought it second hand from my local Gamestation. This wasn't too big of a problem from me as I rip all of the games that I purchase. Nevertheless it had been bothering me so I opened it up last night to take a look at what might be causing the racket. I dismantled it it down to the DVD drive and tried running a game with the cover off to see if I could locate the source of the noise. After mucking about with the metal tabs near the spindle as others suggested with not joy, I then removed the top cover from the DVD drive. Immediately the problem became apparent; there was a snapped plastic tab at the front where the discs slide in. Rather than trying to wrangle it back in, I simply removed it and now it's as quiet as can be.

I also had a third party controller which was making some unwanted noise, specifically from the motor used for vibration. Rather than making the usual low pitched rumble, I was getting an annoying clacking sound. Turns out whoever put the remote together at the factory had forgotten to peel off the paper from the double sided tape, D'oh!

Filed under: Fixes No Comments
18Aug/110

Netgear DGN2000 capacitors

Got around to opening up my wireless router to check for faulty capacitors today. Turns out all three Taiwanese-made Teapo capacitors had gone bad (visibly bulging) and needed replacing. Replacement caps for this router should be at rated to at least 105C, 2x 470uf 25v and 1x 100uf 25v caps are needed.

The repair itself is simple:

  • Remove the four rubber feet and take out the torx screws (T8)
  • Lift off the case and remove the system board
  • De-solder old capacitors, taking note of polarity - the square solder point is positive
  • Solder in new capacitors
  • Replace case and screws

Replacing the two 470uf caps solved the issue of Ethernet port 4 no longer working. I haven't swapped out the 100uf yet, not sure what part of the system it affects.

Filed under: Fixes No Comments
9Jul/110

Dreamcast deminta

Since I've been using my Dreamcast lots lately to archive some of my games, I wanted to do something about the console fogetting the date and time. This is a common fault with all Dreamcasts, where the rechargeable battery inside the console has reached the end of its life and refuses to charge. The solution is to swap out the battery. Unfortunately, unlike the Saturn, SEGA never designed the console's battery to be replaced by the end user.

At first, rather than hunting for an exact replacement for the original Maxell battery, I bought a 3V lithium-ion battery designed for laptops. The  one which I opted for was made by Panasonic which has a higher capacity than the original.

Replacing the battery involves opening up the console, de-soldering the old battery and soldering in the new one as a replacement. After completing the work with the Panasonic battery, a week or so later I came to realise the battery I fitted wasn't rechargeable. Rather it was just a CR2032 wrapped in plastic. While it didn't cause any problems, such as exploding or leaking, I decided to seek out the correct replacement.

The manufacturer and part number of the battery I needed was Maxell - ML2032 T26. The only UK company I could find which sold them was Farnell, a large electronics distributor, who require a business account to make purchases. Luckily a kind soul where I work added 3 to an order he was making, enough to replace the battery in all three of my units. For now I've just done my original console. Now it remembers the time and date like it did back when I purchased it in 1999.

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