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 Bad Pixels Title

Pixels 

 


Greetings from Roger Macie:

The biggest expense for broadcast video cameras is the repairing of bad pixels, or pick-up elements of the “CCD Optical Block”. For those who don’t know what I’m talking about, bad pixels are defects in each of the camera CCD pick-up devices. Manufactures never seem to talk about these but have specifications of how bad they must become for them to replace these very expensive components under warrantee. All typical broadcast camcorders have three “CCD chips, one each for the green, red and blue channels, with at least 400,000 light sensitive pick-up elements called pixels. CCD actually is short for charge coupled devices.

When they fail, these semiconductor elements develop electric potential difference as compared to adjacent pixels. As these are scanned during normal operation, the higher level shows up as a brighter spot on the video monitor depending on which color channel the problem is in. Because it is nearly impossible to manufacture perfect blocks, each one has pixel-masking (hiding) circuits that store the location of the bad pixels and bypasses them, hiding the bad ones. Who’s going to miss a few out of hundreds of thousands anyway? The big problem discussed here is the fact that over time more and more of these pesky pixels fail and often require repair to eliminate those tiny little spots in your picture.

Newer Sony broadcast cameras have what's called APR, or automatic pixel reduction circuits, that mask the bad pixels whenever the camera is auto-black balanced. That usually works for several years until the bad pixel memory fills up and will not mask any more pixels. CCD blocks are usually factory warranted for 2 years against these pixels and require factory replacement CCD block assemblies. The bad pixels must also be visible at a specified video level, usually at 0 DB camera gain setting, before the manufacturer will replace the entire block. If only visible at +18 DB and not at 0 DB, your out of luck.

Why are these bad pixels only visible sometimes? It is due to the temperature sensitive nature of the pixels. A cool camera may seem pixel free even at high gain settings. Leave that same camera on for several hours in a warm room or out in the sun, and all of a sudden it looks like stars at night. The higher the temperature the greater the likelihood of seeing bad pixels.

Whenever we perform pre-purchase check-ups for clients, we leave the camera on overnight to make sure that it gets as warm as it would on the hottest of your shoots. At that point we will measure the video level of each bad pixel measured at the 0 DB gain setting along with the line number and picture zone. It is rare that any older camera is free of bad pixels. As a buyer you want to know if you will soon need block service or replacement.

Three things can be done in the event you have bad pixels. First keep the camera as cool as possible and live with the problem until your clients notice. Repairs seldom take very much time to fix. If your not sure if your camera has the APR circuits, get the camera good and warm and try multiple auto black balances. The circuitry has to detect a certain level before its masking circuits will work. If that fails you have two choices, the first being replacing the CCD block assembly. For BVW-D600, in March of 2002, the cost of a refurbished block was $7,200 and a new one costs $21,000. For a DXC-D30, the refurbished block costs $2500 and new block $4500. Of course labor is additional. By the way, recently in June of 2002, the D-600WS CCD block jumped up to $14,830 for refurbished, and $30,000 for new.

There is another less expensive, better solution. That solution is sending your camera to Lucke's Camera Service, who specialize in Sony CCD block pixel repairs. What they do is actually manually mask each camera’s existing CCD block. Without even removing the block, or changing the camera's settings or look, they hook up a PC to the camera and reprogram the locations of the bad pixels at a fraction of the cost of block replacement.

I have had a great relationship with these guys for years and have been referring our clients to them for the most cost effective CCD block repairs for most Sony broadcast and professional cameras and camcorders. From broadcast and professional cameras to BetacamSP, Digibeta, and recently added DVCAM camcorders, the cost varies with different models from $900 to $1,800. They even have an extended warrantee if you would like. It’s the best repair value in the industry. I have been sending each of my own reconditioned cameras to them for this important service. No one likes to purchase a camera with any visible defects that may have to be repaired at additional cost later on.

While we specialize in preventive maintenance and custom camera set-ups, we recommend them because of their success in saving customers a lot of money dealing with this major camera problem. With shrinking budgets and the need to extend the life of your gear until someone wins the format wars, you need to know this service is available.

You can reach Kevin Lucke at 800- 497-0341 or visit their website at: www.luckescamera.com/CCDBlock.htm  

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