Bio-Rad GS-800™ Calibrated Densitometer - Manual (Page 18)

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Section 6 Troubleshooting
Though the Model GS-800 Calibrated Imaging Densitometer is very reliable, problems can
occur during operation. This section lists some problems and the recommended corrective
actions. Most problems are easily remedied.
6.1 Troubleshooting
Electronic Failure
Call Bio-Rad Technical Service.
Will not scan again, stays in home position, or grinds.
Make sure that the shipping lock down screw for the Transparency module has been
properly unlocked (See Section 2.3). If this still happens then it is probably related to a
mechanical failure somewhere inside the Densitometer. A part may have come loose and
is obstructing the path of the lamp assembly. Contact Bio-Rad Technical Service.
The Power indicator fails to light up.
1. Verify the power connection to the Densitometer.
2. Check that the power switch is turned on.
3. If you have confirmed that there is power to the Densitometer, it is likely that the
Densitometer fuse needs to be replaced. Contact Bio-Rad Technical Service.
The scanned image is marred by specks or horizontal lines.
Hardware failure. Contact Bio-Rad Technical Service.
The scanned image is showing random dark specks.
Clean the image window glass. Refer to Section 5.1 on Maintenance.
The scanned image is marred by Moiré patterns
Moiré patterns are often seen when scanning a halftone. A halftone is a picture in which
the gradations of light are simulated by dots of varying sizes or densities and produced by
superimposing a screen over an image (e.g., pictures in newspapers and magazines). It is
best to avoid scanning halftones because of the moiré, but if it is unavoidable, scan at a
lower resolution.
The scanned image is too dark.
1. If your are scanning a transparent sample, make sure your are using the transparency
selection.
2. If the problem persists, contact Bio-Rad Technical Service.