Page 5.7
Chapter 5
Adjustments
SCHILLER AT-2plus 6-Channel ECG Unit
SERVICE HANDBOOK Issue d May 2002
Paper mark Detector Check
Tools, Equipment and Material
•
Digital voltmeter
•
Small flat bladed screwdriver
•
70% alcohol solution and clean lint free cloth
Procedure
To adjust the paper-mark Schmitt trigger sensitivity proceed as follows:
•
DISCONNECT THE MAINS SUPPLY
•
Open the paper tray lid and clean the photocell (situated on the opposite side to the dc
motor) with a 70% alcohol solution. Allow to completely dry.
•
Disassemble the unit as detailed in Chapter 4.
•
Reconnect the keyboard to the Control board and place the top assembly on its side in front
of the Base assembly .
•
Switch the unit on and set the speed of the printer to the slowest setting of 5mm/s (5mm/s
key).
•
Press the MAN START key to activate the printer. The paper is now moving at low speed
(through the roller and paper mark detector).
•
Check the pulse amplitude at P8 pin 1. (Measure with AC setting, signal is noisy.)
•
no paper-mark
(white paper)
between -80mV and -200mV
•
paper mark
(black paper)
between -5mV and -30mV
•
Reassemble the unit as detailed in Chapter 4.
