I have this Casio alarm clock for well over 25 years now. This alarm clock followed me from home to my new country in Perth Australia, and is a reliable workhouse - never fails to wake me up for all my exams and so on. Once I entered the workforce I’ve established a good biological clock routine and do not need for the use of a alarm clock again - but this clock stayed faithfully by my beside table till now.
The one feature this clock has is the EL backlight - high tech in it’s day, it’s something of a dated relic now with today’s OLED and backlit displays.
I love this clock, but there is something that annoys me always. There is this high pitched noise whenever the EL back light is lit. My curiosity is piqued when my wife commented she can only hear this noise when the clock is right by her ears, about 10 centimeters or more away she could not hear this noise any more. Definitely a no no when it’s more than 30 cm away. On the other hand, I still manage to hear this hum with the alarm clock an arms length away, possibly further.
Via my phone app, the the tones of the hums - 2.8 kHz, 4.3 kHz and 7.1 kHz.
All three bands and its amplitude are well within the human auditory spectrum. And yet my wife cannot hear it while I can. Why? Do I have super ears? The answer sadly is no.
I have a Denon DVD-2930. Used it primary for CD/SACD playback in my HT setup. And it works fine. The only drawback is that it couldn’t play DVD-Rs. After a few minutes the player will just freeze. The player is also very noisy in general. Updating the firmware improves stability but I’ve never got DVD-Rs to play. It’s not an issue for me because I don’t use it to play movies. But since I have too many DVD/SACD players. Why not chance it and try replacing the laser?
So in the end I’ve ordered two lasers from e-bay. Purchased a soldering station and a earth wrist strap from Jaycar. And went on replacing the laser.
With a new laser. I’m surprised that everything still works. Not only that, DVD-R discs seem to work now. And the unit is a lot quieter. So the minor hassle I had with DVD-R turns out to be an aging laser, a laser that’s in use for only 183hrs..
Follow the steps below to replace the laser.
Unscrewing the player and removing the optical unit is easy. Here are the steps I did (from memory) *:
Eject CD tray.
Power off and disconnect. Work on a clean table with a clean floor
Remove top cover
Remove RFI/EMI shield
Remove DVD drive unit shield
At the top of the DVD drive unit, there’s a plate with 2 screws. Remove them. This gives you room to remove the two rails/rods.
The lower end of the left rail has a screw preventing you from lifting it up . Loosen that then move it out of the way.
Lift the two metal rails up gently, and remove it carefully.
There’s a small spring on the white lever gear. Make sure you don’t drop it while taking it out. This is very important!
Earth yourself with the anti-static strip
Remove old laser, and replace with new one
Follow the above steps in reverse to refit the laser assembly. Ensure the spring in the white level wind gear is still in place.
Manually slide the laser head up and down the rails to check that everything is moving smoothly.
Start your soldering iron and remove the shorting solder on the optical laser head.
Refit the DVD cover, the EMI/RFI shield, and the top cover.
Turn on the unit, go to test mode, and save the the lasor units (refer to the service manual).
Save the new values. (This will give you a reference as to when the optical unit requires replacing again.)
Reset the laser hours. (Keeps track of how many hours before the laser dies again)
Reinitialise the player (it wouldn’t play CD properly without this step)
I’ve no idea if it’s correct to go into Test Mode and reset the laser numbers. But I did that anyway and everything seemed to work. You must reinitialise the player after resetting the values. Else it will not play anything at all. Refer to the service manual on how to get into test mode, how to read the laser values and how to save them.
The new laser’s value is 3025 for me, but I assume every laser unit is different. Time will tell how long this second. For a $10 AUD part, not that bad..
* Disclaimer: Of course you are doing this totally at your own risk! I am not responsible for any damage to yourself or your property.
With the advent of computer players we are seeing more and more examples of people saying high power (i5, i7s and Xeons) or FPGAs are better than the Digital to Analog Convertor (DAC) chips of old.
This claim is debatable, there are certainly some cases where this statement is true.
All processors work the same way at it’s most basic level- it recognises 1s and it 0s. The difference is the kind and type of operations each type can perform on these binary stream. There are trade offs between power consumption, calculation speed and flexibility as you look across the board.
Computer Processing Unit (CPU) from makers like Intel and AMD are what we call General Purpose Processor. These chips power the computers we use today. It has the largest instruction set, is capable of having the most applications, are highly adaptive and can be customised to perform jobs like playing games, word processing, internet web browsing and more. The downside is the high power requirements (to power all the extra transistors).
The complexity reduces as you move from CPU (most complex) → FPGA (somewhat complex) → ASIC (least complex). There are a lot less components in the ASIC when compared to the FPGA. There are so many components in a general CPU, and packed so tightly we need a heat spreader over it to conduct heat away.
Went to the Adele Perth concert at Domain Stadium last night. The performing stage is amazing, and we got good seats. That is a 360 degrees video wall and the eyes open up when the show begins!
Alas the sound system is just not up to scratch for a wannabe audiophile like me. Compression is an issue - like all the released albums.
Still there is no stopping this charismatic, jovial and quick witted performer. She has the ability to light up the room, any room. And she definitely lit up the 100 year old stadium with about 65000 singing, dancing fans!
It was an enjoyable night, and bonus points for the awesome weather! Given a crowd of 65,000 headless choooks1, I expected the worse. We took public transport to and from the venue, and kudos to Transperth’s organisation as the experience is extremely smooth and pleasant back and forth.
I’m sure people will complain on Twitter about how they are delayed by this and that, but for us we are back home real quick. There are clear signs indicating where the pick up/drop off points are, and all in all it was a pleasant experience. Well done Transperth!
More grainy pictures after the link. Great event to mark the first anniversary of the Snakeoil OS yesterday.
Footnotes: 1: For everybody else outside Australia - Chooks is Aussie slang for Chickens. As for what headless chooks means, honestly I have no idea!