Sunday, October 24, 2010

Sony XC995 Repaired!

After tracing the spindle driver electronics, I determined that the controller was not even attempting to spin the DVD for some reason. That reason must exist somewhere earlier in the disk reading algorithm. Now I was starting to fear I would have to replace the whole DBU-3 optical assembly, available for about $99 on ebay.

I tried to re-calibrate the drive through the diagnostic tools built into the player (press Edit-Clear-Power in sequence while in standby). The calibration required loading a single layer DVD, audio CD, and a dual layer DVD. The calibration utility did not seem to help. No DVDs would even spin up. However, the audio CD I loaded for calibration started to play! So clearly, the hardware detecting the media type even before spinning it up. For some reason focus on DVDs was not possible. In retrospect this makes a lot of sense - it is probably much easier to focus on a non-moving target. Failure to find focus would result in the drive rejecting the disk.

Next time I loaded a DVD up, I pulled the disk a short distance away from the lens by sticking my finger inside the drive. I saw the lens focus and the spindle started up! Of course, it would not work with my finger sticking in there, but this was an excellent sign!

Now, in my initial attempt to debug this I had removed the spindle motor. This involved removing the plastic hub from the spindle shaft. Upon re-assembly I pressed the spindle hub on to approximately the same location as I found it. It turns out that the original hub installation had likely been pressed on a hair too much. Perhaps after a 1000 CD loads, and a bit of mechanical wear, DVDs started to be loaded just outside of the focus range of the optical system.

The repair was simply removing the spindle hub and re-installing with about 1/8" of clearance. Now everything is working!

Friday, October 22, 2010

Busted DVD player

Wow! Over 1.5 years since last post!

My Sony CX995V DVD jukebox stopped working last week after 4 years of relative reliability.

Some investigation indicated that the CD spindle was not rotating after loading each disk. My first thought was that the spindle motor must be bad. I spent time taking the whole thing apart and removed the spindle motor. I hooked it up to a 5v power supply and it spinned up like a champ. Drat. Now I had to figure out if the motor driver was working. I managed to locate some teeny tiny test points for the spindle drive voltages and solder some wire wrap wire onto them. Sure enough, no voltage across these points. Manually rotating the spindle motor did generate some measurable back EMF, so everything is hooked up properly, just no juice. Turns out this is driven by a Fairchild Semi servo IC designed specifically for CD drives. It has 5 output channels to handle all the various motors in a modern CD player: sled, spindle, focus, etc... Now it seems that all the other functions of the drive are working. I can see the sled move back and forth, the optical assembly was definitely trying to focus. So the IC seems to be mostly functional. Next step: test the inputs to the motor driver to verify that the controller is indeed trying to spin the CD when it is supposed to. My prediction: it is NOT going to be sending a signal to the motor driver IC. If it is just the motor controller chip, there is a SLIGHT chance I could locate a replacement chip and repair the main board. If I have to trace this thing back much further, I will probably run out of leads as to what needs fixing.

Wednesday, January 28, 2009

Friday, August 8, 2008


We host many wasps in our pond in the back yard. They seem to enjoy going for the
occasional dip. Now I don't really mind if they come for a quick swim and a drink, but things got serious when they start stinging my kids and building condos in the toy chest.

The local hardware store carries some wasp killing chemicals. Enter ULTRA-KILL:

Interesting how Ultra-Kill is the brand, not the product name. What else do these guys make?

Thursday, August 7, 2008

I Love Rockets

I have been keeping an eye on the new NASA moon program. There is a lot going on there which isn't getting much publicity. They are working on new hardware the likes of which we havn't really seen since the 60's. Check out this test firing of the emergency escape motor for the Orion capsule:

It is very short, but packs a lot of power!

Tuesday, August 5, 2008

Fun in the Sun

It's been a while since I have posted. My wife and I were actually able to go out and have some fun over the weekend, so I thought I would share some cools stuff in Denver:

The Denver Botanic Gardens were pretty good. I wasn't expecting much, and was favorably impressed. Lots of native and Colorado tolerant plants. Many were labeled (but I was recently informed that they labels are often incorrect) There are a number of water features, and a fair Japanese style garden (especially considering the Denver climate). Admission was a bit steep ($10.50) but parking was free and convenient. There are numerous small paths around the gardens. Some of them are unpaved giving a more intimate feel. It is mostly stroller accessible. I didn't catch the membership fees, but if I lived closer it would probably be the way to go. I am sure the scenery changes throughout the seasons. There are fees for professional photographers (which are a bit steep if you ask me)
One down side was that they host many weddings there. The had signs up to close many of the attractions for ongoing ceremonies. We were fortunate to be there between most of the weddings and got full access.
One pleasant surprise was the abundance and variety of bees we saw. I imagine they were just about the happiest bees around with all the flowers available.

More later.

Wednesday, June 25, 2008


XKCD is one of my all time favorite comics. It is at the very least amusing. Sometimes it clues me in to an internet meme which I missed out on (I probably have 10 years on Randal, so I am a little outside his demographic). There is frequently something of value to be learned. And once in a while it hits me as the funniest thing ever.
Today hits a little close to home.

Check out the archives. There are some great ones in there.

Tuesday, June 24, 2008

And the spinner was detected

I had some time to run my sensor on the real meter last night and was able to read the spinning disk with some reliability. It was not in full sun, so that test remains. I didn't drag my oscilloscope outside with me, so I don't know how close I got to saturation, but I am now hopeful. There was some noise in the output when pointing the sensor on the edge of the disk (it has a surprising number of imperfections). I had better luck moving the sensor above the disk and pointing it down.
The next step is to optimize the design by removing any unnecessary components, and cleaning up the output to produce a clean digital output. I also have to figure out how to mount the thing nicely.

I will be connecting the sensor to a microcontroller and sending the resulting data out via a wireless link to my main computer. The plan is to put the data on the web.

I created a first pass schematic including the microcontroller, I was able to route it all on one metal layer, which simplifies things from a manufacturing standpoint. This is important because I manufacture the boards myself, and have no plated thru-holes! I'll post the final design when I am done.

Monday, June 23, 2008

The vomit maker goes on vacation

This is one of my infrared shots from a trip we took pre-children.

She was still pretty much a puppy here, but she did a nice job sitting still for this shot. I believe this was in Jackson, WY. I don't know the story behind all the antlers, but I believe they were collected from a nearby wildlife reserve.

West Nile

Guess what happened to me in 2004.

you can clearly see Colorado's northern front range in this map.

We have signal

After messing around for a while I am getting good results with my phototransistor design by using AC coupling and some opamp buffering and a gain stages. Next up is to see if my phototransistor gets saturated in full sunlight. To get around it, I might have to add some IR filtering. Shading the meter would be a good option, but I think the electric company might have issues with that...

Oh, if you are just tuning in, check out my power post to get some context. This is my device for optically reading the spinning disk on my electric power meter so that I can compute peak power demand and make an informed decision on changing my electricity rates.

Friday, June 20, 2008

A box full of awsome

For my wedding anniversary I received a great geek gift. Theodore Gray is someone I would greatly enjoy hanging out with. He appears to have a rocking workshop, and a fantastic collection of almost all the elements in the periodic table. He also does some kick-ass photography of his items. Furthermore, he went ahead and put it into an attractive poster and sells it.

This poster can be seen in the background in many of the Mythbusters scenes. I got the 22"x44" size, which is a good healthy poster size. There is an even bigger one available, but that one would have a hard time fitting in my laboratory. (Note that these are an odd size, and custom framing is required if you decide to go that way)

Utilities - a history

Playing around with the very cool Google Docs today. I went ahead and populated a spreadsheet with my utility history. The charting features are somewhat lacking, so I couldn't do a very fancy graph, but here it is anyway:

It would be nice to annotate the graph with significant events, like the winter months during which the waste water rate gets computed, and the summer months when the AC is on. Also, it would be nice to have a dual Y axis range. In this graph, I had to multiply KWH/day by a factor of 10 to keep the ranges similar. Yucky.

I took the first steps to design an automatic reader for my electric meter and bought a IR phototransistor and an IR emitter. My fears were that a simple phototransistor would not be sensitive enough for this purpose. So far, my fears were justified. I am going to do some signal conditioning with some active filters and see where that takes us. If the phototransistor is a bust, then I will purchase a nice PIN photodiode with a built in amplifier. If THAT fails, I may have to resort to designing some sort of optics to reduce the noise level to something reasonable.

Friday, May 30, 2008

Kill A Watt

Well the P3 Kill-A-Watt showed up today. Pretty nifty gadget. I ran around and checked a couple of appliances today. As a result of this, I am putting my main computer into standby mode after an hour, this change alone may save me 5$/month. I checked the other computers, and they were already automatically going to standby mode after a period of time, so no real gains there. The Tivo and satellite receiver consume about 47 watts together - these pretty much need to be on all the time. I have 2 of these, for a total of almost 100 watts going 24/7/365. Thats about $4.75/month. The stereo was taking about 30 watts as well, and we don' t use that one very often. I'll just manually turn that sucker off when we are not using it.

I have updated my spreadsheet to reflect these readings, but there is much more to be done.

Wednesday, May 28, 2008

Big Spreadsheet

I did some math last night based off some guesses as to my power consumption. I modeled my power usage in a nice spreadsheet. The model is telling me that my savings are going to be much less than I initially thought. It is also telling me I am using more power than the utility company is metering. I decided to order a kill-a-watt meter so that I can get a more accurate power model.
This only solves part of my problem because my biggest power loads are 240v hard wired appliances. This includes an electric clothes dryer (maybe 5500 Watts) and the central air conditioning (about 3500 Watts). I need to know my peak power profile in order to have an accurate cost model. A good solution is an optical meter reader which just reads the spinning disk on the power companies meter. I have never used one or know anything about these. The theory is sound. The formula to compute instantaneous power consumption from Wikipedia is: Power=(3600*7.2)/t where t is the amount of time one revolution of the disk takes. I am thinking about making my own meter reader, but it might be a little tricky as my meter cover is not very clear. Would be fun tho.
I'll update again when I get the kill-a-watt and post my power numbers.