Source of Hot Pixel Readout Line???

[joelshort]

I've been struggling with a "hot pixel readout" line that sometimes appears in my lights and darks, and I've been trying to determine what causes the line to appear sometimes, and not appear other times.  I have been told that these hot pixel readout lines are not uncommon in CCDs (I have Atik 383L+ camera).  I have attached an dark that shows the line I'm talking about.

For example, last night I took 7 lights, and then after the clouds rolled in I took 33 darks. None of the lights showed the hot pixel readout line. The first 12 darks also did not show the line, but the remaining 21 darks did show the line clearly. Also, a few days ago I took some lights of the same object, and those lights all DID show the line. So it seems as though this line comes and goes.

Does anyone know potential causes for these lines or how to reduce the likelihood of them appearing?

The good news is that these lines do calibrate out, but I have to keep a library of darks WITH the line, and a library of darks WITHOUT the line, and then I have to examine each light sub directly to see if it has the line or not, and then match the darks to the lights. I sure would like to eliminate the line so I don't have to go through all this every time...

[bwa]

I had a QHY9C that had a similar problem.  QHY replaced the camera and (probably) refurbished my returned unit...  However, the bad column on the QHY9C was top to bottom and consistently present.

[joelshort]

I have been told that this is not a "bad column" because it does not extend from top to bottom, but that this is "hot pixel readout" since it goes just partway from middle to bottom.  I've also been told that this is somewhat common in KAF-8300 chips, regardless of the camera manufacturer, and that it should calibrate out.  My problem is that it seems to be inconsistent, and I don't know if there is some other factor in my system that is contributing to the line being present or not.  Perhaps a power issue is causing it?  I just don't know.
joel

[bwa]

I've also been told that this is somewhat common in KAF-8300 chips, regardless of the camera manufacturer, and that it should calibrate out.

My QHY9C also had a Kodak sensor and the column flaw was considered a warranty replacement, even after 18 months of use.

bwa

[joelshort]

Well...now I'm thoroughly confused.  Someone elsewhere suggested I take Bias frames and take a look at them.  (see attached image)   All my bias frames clearly show a column defect that extends from top to bottom.  So this is not "hot pixel readout" as I originally thought.  But this is all so confusing because none of my darks or lights show a column defect from top to bottom, they all show a partial line or no line.

Any advice much appreciated.