Polaroid ID-3000, Repair Manual

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Polaroid ID3000 Service Manual Calibration Procedures
4-19
as their respective value ranges from black to very bright.
The Linearity Test prints the tennis court pattern of eight circles of two different
sizes as shown below, to check CRT linearity.
Distance A should equal distance B within 1/16", and C should equal D within 1/
16". Moreover, the circles should be round and not elliptical.
If these characteristics are not present, linearity should be corrected (see steps 1 -
11 on page 4-7).
The Resolution Test prints checkerboards ranging in width from one pixel to 10
pixels. This test is used during manufacturing, for checking CRT spot size and
focus. Pixel size should increase linearly, from the lower right corner of the print to
the upper left corner.
The Gray Squares test prints 16 squares ranging from black to white, for verifying
gray scale linearity with a densitometer.
Sixteen squares should be clearly visible: if they are not, check film to see whether it
is out of date. If the film is fresh, go to Gentest and check Brightness.
The Character Resolution Test prints an entire field of E’s, for checking focus
consistency over the entire film plane. The E’s in the four corners of the film frame
should be as legible as those in the center. If they are not, check the film date. If
the film is fresh, perform the Electronic Focus Calibration procedure (see page 4-12
of this section).