Service Manual Ponygraphic
Chapter 3
Part Description
3.5
3.3. Display
Assembly
(C01344-01-30)
3.3.1. Function
The display of pony graphic is the main interface for user to enter the patient details , to view
the results and to print a particular test performed by the patient and for all the control functions
to be performed.
3.3.2. Description
The LCD display is CPU controlled by means of the Data Bus (B0-B7) and powered with the
following voltages (see the Display layout in Schematics and Layouts section):
3.3.3. Adjustments
&
checks
(1) Display contrast adjustment
Adjustment VR
Test Point
Adjustment Item
VR54 Display
Display
contrast
It is automatically compensated for temperature variations.
(2) Test Points
Pin 3 of P1
Digital Logic supply (VCC 5V)
Pin 5 of P1
LCD supply (VEE-18V)
Pin 4 of P1
Contrast level VDAJ(-15V)
Pin 1,2 of P1
back-light supply (VEL*90VAC)
3.3.4. Assembly
Drawing
3.3.5. Warnings & Indications in Event of Failure.
•
Display failure
•
Backlight failure
3.4. Keyboard
Assembly
(C01352-01-15)
3.4.1. Function
The keyboard is the primary input device for the patient data and for executing the test it is
passive device hardwired to the CPU.
3.4.2. Description
The keyboard is directly interfaced with the I/O ports of the CPU by the connector JP7.
Pins 12-13-14 of U1 are outputs while pins 33-34-35-36 Inputs.
3.4.3. Adjustments & Checks
There are no adjustments to be performed on this assembly.
