How to test for scratches on blank disc?

vbimport

#1

is there a way to test a blank used CD for scratches or bad sectors? or this can be done only after burns ?


#2

You can look at it for scratches, usualll the top and bottom discs on a spindle are the ones to watch.
There’s really no such thing as “bad sectors” on a blank CDR. A defective disc may have an area that is “bad”, but there’s no way to test for it, again other than looking.


#3

Originally posted by rdgrimes

but there’s no way to test for it, again other than looking.
Well, unless you buy yourself a special equipment that will allow you to “measure a CD-R that contains no data”.
Then your test result might look like this :


#4

Oh… That’s looks cool !

thanks for the help


#5

Originally posted by MrMaki

Oh… That’s looks cool !

I’d rather say it’s HOT :bigsmile:


#6

he he :bigsmile: :bigsmile:


#7

> Then your test result might look like this :

Except BLER cannot be measured on a blank disc.


#8

So there is no other way. I have to burn data on it to see if it’s usable.


#9

Originally posted by spath

Except BLER cannot be measured on a blank disc.
Yes, BLER is being measured on written data.


#10

A CATS-machine is a little on the expensive side for home users I’d say :bigsmile:


#11

Originally posted by Airhead
A CATS-machine is a little on the expensive side for home users I’d say :bigsmile:
Right but it’s a one-time and worthy investment . :wink:


#12

> Yes, BLER is being measured on written data.

Then replace the picture instead of tampering
with it.

As for cheap testing of blank media, one could
try ATER measurements.


#13

@spath,

Gotcha ! :wink:

I too like your more and more fashionable way of talking to people.
But you must replace it and this is my kind advice to you.


#14

Just to make things clear for everybody : the original question was
about testing defects on blank discs and you decided to mention special
test equipment in your first reply. Unfortunately you chose to add
a picture of a bler plot, which precisely cannot be obtained with
a blank disc.

When I pointed out that this plot was not matching the question, you
edited your copy of the picture and removed the “BLER” word from it.
For reference, the original picture is at
http://www.audiodev.com/default.asp?GROUPID=200212182253314071

What exactly is the point of this modification ? Just removing the
legend doesn’t make your post correct and can only confuse people
reading this thread. If I now tell you that I can still recognize
a CATS BLER plot from the scale on the right, will you further
edit the picture ?


#15

Just to make things clear for everybody :

The question was: can one test a blank disc for quality.
The answer is: for all intents and purposes, the casual user cannot do this.
I think this thread has out-lived it’s usefullness.
Perhaps a new thread should be started to discuss the other issues.