Archive for the ‘Information Technology’ Category

Audio data recovery from external USB drive using ddrescue

Wednesday, June 30th, 2010

High resolution audio and video digital tape conversions can use large amounts of computer storage. 8 bit uncompressed Standard Definition (SD) PAL video runs at 70 GB per hour and 24 bit 96 kHz audio files at 2 GB per hour.

As a result of this many of our analogue to digital tape transfers require the use of external storage, usually USB 2.0 portable hard drives, to supply the copied digital transfers back to the customer. Some drives supplied by customers have not been of great quality and not designed to be sent about in the post. One such drive we had recently, a Sony Vaio branded 2.5″ USB drive wouldn’t copy certain directories of important files with the Mac OS Finder or the Windows Explorer. While most of the drive copied this certain folder always resulted in a crashed computer!

Thanks to GNU/Linux we have a bit more power and information at our disposal about hard drives and IDE or USB interfaces. It’s always best practice to copy as much information from the drive or mirror it before attempting any other types of data recovery or file system repair. Using the standard dd

HTC Desire in the toilet

Tuesday, June 1st, 2010

HTC Desire android mobile smart phone

Not our normal type of post but the new HTC Desire Android smart phone has been so useful with it’s open source applications, fast speed and wifi that I couldn’t believe I’d just put the phone in my shirt pocket and leant over the toilet!

Panicking, I fished it out and messed about trying to shut it down, when I should have just whipped the back off and the battery out. I did manage to get the battery out pretty quickly but not before I’d seen the screen start to make weird colours and odd lines. The thought of buying a new phone at full price was too much so I pulled out a handy bottle of Isopropyl alcohol (IPA) we use for cleaning tape and video record and repro heads. This is 99% pure IPA, not cheaper ‘rubbing alcohol’ that is often 70% IPA with 30% water. You really don’t want to make your phone any worse!

When I’d calmed down a bit I checked the moisture pads that show if the phone’s had water contact. These had gone pink confirming the toilet dunking so no warranty repairs here! Having little to lose I removed the 4 small torx head screws and the two even smaller crossheads screws under the rear cover. Two of the Torx screws have ‘void’ stickers over them so again once you undo them you’ve lost your warranty!

Now the bottom cover over the USB connecter can come up as can the inner cover which will reveal the wifi / bluetooth aerials. I didn’t remove the screen but ‘carefully’ poured IPA all over the bits that smelt of wee!

99% pure IPA will evaporate very quickly but any residual moisture should go before you can think about putting the battery and other cards back in. Many online sources recommend uncooked rice to absorb moisture but purpose made desiccants are best. I used several silica gel sachets in a freezer bag with the disassembled phone and left this overnight.

Thankfully this all worked, the phone starts, the screen works it’s alive!

The key points when you have this kind of phone disaster are:

  1. Get the phone out of the water / wee
  2. Get the battery out as soon as possible
  3. Remove all the SIM / memory cards
  4. Shake or carefully pat dry as much liquid as you can
  5. Any liquid contaminant that isn’t pure water and contains sugars or salts must be cleaned off
  6. If you try IPA make sure it’s high purity 99% is best

Finally, we’re tape transfer specialists not phone repair specialists so I offer no guarantee with all this but it did work for me.

windows user interface button problems

Tuesday, October 27th, 2009

An odd, frustrating but very easy to fix problem appeared on a old Windows 2000 Professional system recently.

The check boxes, task menu arrows and window minimise, maximise and close graphics all changed and made some aspects of the OS more difficult than usual to use. The user thought a virus  or spyware had done this but after realising that these parts of the Windows user interface are characters from a TrueType symbol font, Martlett, the solution is trivial. As in print when a font is missing, software substitutes it with another one that usually always looks odd.

The font was installed but corrupt, using a copy of Martlett from another install fixed the problem immediately. MS has something to say about this here: http://support.microsoft.com/kb/134861

greatbear analogue and digital media have moved…

Wednesday, September 2nd, 2009

not far though – just upstairs to a much roomier space with better natural light.

Anyone who’s visited will know how much equipment we have and this move has meant quite alot of downtime as we’re taking the opportunity to re-rack, redesign and re-wire. Anyone with existing orders will have these processed as soon as possible but please bear with us for the next week or so….

Our revised address is:

greatbear analogue and digital media
Unit 26
The Coach House
2 Upper York Street
Bristol, BS2 8QN

0117 985 0500

To contact us by email, please use our contact form here…

Focusrite Saffire LE SPDIF problems

Monday, February 23rd, 2009
Focusrite Saffire LE

Focusrite Saffire LE

I’ve owned one of these Saffire LE firewire interfaces for a few years now and it’s very useful as a backup to my RME interfaces especially when I need to record and transfer audio at another location as it’s small, light and portable. It’s a very good sounding interface and  it even is reported to work under Linux which I’ve tried but unfortunately not with Audacity as this that doesn’t use the Jack server.

I’ve had an ongoing issue with the SPDIF inputs though. Under Windows XP and MacOS X it refuses to record more than a few mninutes if locked to another digital unit such as DAT machine and the Saffire software reports the firewire interface has lost it’s connection. This has rendered all SPDIF transfers impossible to do correctly.

The support at Focusrite is very good, you can actually speak to someone! We tried using an external power supply unit (PSU), different firewire cables, checking the type of firewire interface in the Windows machine and upgrading the firmware under MacOS X but all to no avail. This is a repeatable issue under several different computers and OS’s.

Acer 1360 laptop motherboard replacement

Wednesday, January 14th, 2009

I recently had a dead Acer 1360 laptop on my hands.

The power supply tested fine so it seemed likely the main board was at fault. This is a one piece board and of course it requires a full dismantling of the laptop to remove and replace.

I took a chance on an eBay board that arrived badly packaged and wrapped in bubblewrap not anti-static packaging. It stank of nicotine too!

acer_1360_motherboard

Acer 1360 bare motherboard

Disassembly was quite easy. Only three types of screws, big and small black and silver, very idiot proof. I didn’t have a service manual or takeapart guide but this is what I did, no pictures I’m afraid:

  1. Connected my ESD wrist strap.
  2. Remove battery, hard drive, ram and wireless cards (easy!)
  3. Remove the four small silver screws in the battery compartment.
  4. Gently prise off the small covers around each screen hinge.
  5. Remove more silver screws and remove button / fan plate, keyboard and top cover (can’t remember the order but it’s quite obvious)
  6. Gently prise up ribbon cable connectors and remove keyboard and trackpad cables.
  7. Time to remove the screen – The power and video connectors on the main board need to be removed, this needs very small fingers but I used a small ceramic screwdriver to help prise it up.
  8. Remove the two black screws each side holding the screen to the main laptop body.
  9. Put screen somewhere safe while feeding the two wireless antenna cables out.
  10. Start removing everything else! All the long black screws from underneath and all the small silver screws inside the laptop some holding metal shielding.
  11. Hopefully now you should be down to the bare motherboard – remove it and put your new one in!
  12. I hope you remembered the order all the bits went back on? It’s got to be right and there’s a few bits that have to be done in the right order on assembly.
  13. I found I had to remove some parts from the old motherboard that were missing on the replacement one.
  14. Have you got ALL the screws?

I found that my new motherboard worked perfectly first time all apart from the Trackpad and buttons! We just used an external mouse instead!

acer_1360_damage_detail

Damaged inductor

I did find out later that the original damage had been caused by a heavy fist slamming into the trackpad in frustration with Windows. Inside the case there were some plastic parts that had broken off one of these inductors. This would also likely explain the broken trackpad……

PC World terrible customer service and support

Tuesday, July 8th, 2008

altered pc world logo

A customer recently came to me after an unhelpful, incorrect and ultimately expensive experience at PC World.

Their Dell Inspiron laptop had stopped working, after initially refusing to look at it, the ‘tech’ person grudgingly agreed after a complaint to his manager. After being told it was thought the power supply had stopped working, he took it away and ultimately concluded the motherboard needed replacing.

Of course it didn’t and just needed another power supply which was less than £20.00 for a recycled one on eBay!

Unfortunately the customer had already bought another laptop on this expert’s advice which she didn’t need. Please don’t go to PC World for advice!

Advent 7055 laptop overheating repair

Thursday, May 8th, 2008

Advent 7055 running Ubuntu 8.04Just recently I’d been asked to repair what seems to be a common problem with PC type laptops over a couple of years old. Dust gets trapped in the copper fins and the fan of the CPU heatsink and reduces the efficiency of the cooling resulting in regular power off’s by the laptop as it gets over it’s upper temperature setting.

The fix is relatively easy, remove the heatsink unit, blow it clean with compressed air, clean the old CPU heatsink paste off with isopropyl alcohol (IPA) and spread a thin but even film of good quality heatsink paste on the CPU. Put it all back together, keep your fingers crossed and it should be fine!

This has fixed several laptops permanently and with this Advent I could go ahead and wipe the old Windows XP Home from it and install Ubuntu 8.04 that’s fantastic and  installs perfectly without any ‘geeking around’ necessary. My only problem is the fan control from linux, but that’s another story……


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greatbear analogue and digital media ltd, 0117 985 0500
Unit 26, The Coach House, 2 Upper York Street, Bristol, BS2 8QN, UK


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