ELCOM Euro-50, Service Manual

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Euro-50 Service manual
30
Elcom s. r. o.
The description for removing malfunctions assumes that the cash register contains the software that was originally
supplied to the customer.
Prior to replacing any components on the motherboard, measuring for shorts or values of passive parts, it is necessary
to unplug the power adapter, accumulator and all cables connected to the external interfaces.
4.1. Supply voltage for the cash register
Table 4.1. List of supply voltages
Name Typical value Description
VRAM 3V Backup voltage for RTC and external RAM
VDDQ 3,3V Main supply voltage
VDD 1,8V Supply voltage for microcontroller core
AVDD 3,3V Supply voltage for AD converter
AVREF 3V Reference voltage for AD converter
VDDQSW 3,3V Supply voltage for printer logic, LEDs of end of paper sensors, and platen position sensor
VLCD 3,9V až 4,5V Supply voltage for LCD - character display
VLCD 3,3V Supply voltage for the LCD - 7-segment display
VH 6-8,4V Supply voltage for printer thermal head
EXT5V 5V Supply voltage for external equipment. Brought to the connector of serial port COM1
VIN 12V Supply voltage from the external adapter
4.2. Display malfunctions
4.2.1. Incorrect images on a character display
Table 4.2. Procedure for solving incorrect imaging of a character display - cashier display
ID Test Steps in the case of an unsuccessful test
1 Check the connection of the display to the motherboard
Adjust the loose cable. If the FPC cable is damaged, the display
must be replaced.
2
Check the supply voltage for the logic of the display
VDDQ
Check C1, connect to XC2. (E50MB.pdf, list disp-fm.schdoc)
3 Check the supply voltage for LCD-VLCD
Check C2, connect to XC2. Increase the brightness of the charac-
ter display in the service menu of the cash register. (E50MB.pdf,
list disp-fm.schdoc)
4 Replace the display with a functional one
5 Launch the cashier display test (102)
Check whether a short has occurred between signals DISPDA-
TA-1, DISPCLK-1, DISPRST1-1. Check the progress of the signals
DISPDATA-1, DISPCLK-1, DISPRST1-1 to connector XC2 with an
oscilloscope.