Page 3.4
SCHILLER AT-2plus 6-Channel ECG Unit
SERVICE HANDBOOK Issue d May 2002
Chapter 3
Fault Diagnosis
Printer Check
To check the printer and to ensure that every pixel is operational, a built-in printer test is provided.
To carry out the printer check press:
ALT - MAN START
A test printout is given. Four test patterns are available - toggle between the test patterns with the
lead arrow keys up or down.
Carefully examine the printout and ensure that all the lines are even and uninterrupted. Any
faulty print-head pixels will be seen as a horizontal white line. Examine the printout for evenness
of print.
If a faulty pixel is detected the printer must be replaced. If the printout is uneven (for example
darker at the top than at the bottom), it indicates that the printer alignment is not correct. If the
printout is too faint or too dark, check the TPH temperature in the self test printout given in
Chapter 5. Also check the paper; old paper, paper that has been exposed to light for a long period,
or poor quality paper can all adversely effect the print quality.
NOTE:
THE ‚SHELF LIFE‘ OF THE PRINTER PAPER IS NOT INDEFINITE. OLD PAPER,
PAPER THAT HAS NOT BEEN STORED IN A COOL DAMP FREE ENVIRONMENT,
OR PAPER THAT HAS BEEN EXPOSED TO EXCESSIVE HEAT CAN ADVERSELY
EFFECT THE QUALITY OF THE PRINT
Print Head Alignment and Print Head Tension
The print head tension (the pressure that the print head exerts on the printer paper) is achieved
with two spring exerting pressure on the print head: the print head tension cannot be adjusted.
Similarly print head alignment is fixed and cannot be adjusted. If the print head tension or print
head alignment is not correct change the paper tray and printer assembly.
Possible Printer Problem
Corrective Action
Paper jams or does not stop at
correct position.
Clean paper mark detector with a 70% alcohol
solution. Allow to dry completely.
Ensure that good quality, fresh paper is installed.
Change the Printer Motor driver board.
Printout uneven; Fading at top or
bottom.
Check evenness of spring pressure of the printer
to roller.
Check roller for wear and symetry.
Clean print head (pixel array) with alcohol.
Ensure that good quality, fresh paper is installed.
Faulty pixel.
Clean print head (pixel array) with alcohol.
Replace printer.
Printout too faint or too dark;
General quality poor.
Carry out the strobe timing adjustment detailed
in Chapter 5.
Clean print head (pixel array) with alcohol.
Ensure that good quality fresh paper is installed.
