Innomed Medical Heart Screen 60 G, Руководство по обслуживанию, Страница: 12 / 84

Innomed Medical Heart Screen 60G-80G-L Service manual
2014.01.09 12/84 D-5450-1-B_HS60G80GL_SM_ENG.doc
5.3 HS80G-L Main board digital part
(D1127B_HS80G-L_Main_Board_Electrical_Sch)
5.3.1 Main functions according to the connection diagram:
6/9. Processor
Among other things it contains the microprocessor (U24)
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the 512kByte external RAM (U29),
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the calendar IC (U21 RTC),
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and the serial digitized ECG signal receiveing readable 2 8-bit registers (U37 and U39) (APM Input Register).
All these connect to the common 8-bit data and 19-bit address bus.
Located here as well:
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Test connection (J3) (see below board version descriptions)
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Interface Board connection receptacle (J2) (see below board version descriptions)
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Reset signal generating circuit
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Programming mode switching circuit part (with the Reed tube)
7/9. Power Supply
The most important of these circuit blocks is the U52D-U51A-T2 trio, turning the device on and off.
Beside them is the U92 bus switch, which controls the speaker and the automatis shut-off feature.
This is where the circuit creating the reference voltage required by the device’s dgitial circuit parts (U43A).
The switching power supply with U44 ensures the voltage for the digital circuits.
A separate circuit is there to supply the RAM for stored records and the clock-IC with power when the device is shut
down, by draining the battery.
The largest circuit block on this side is the circuit ensuring PC serial transfer. The main parts of the circuit are the
safety power supply (U86-TR2) and the opto-connectors realizing two-way connection (U80-81). The power supply
automatically turns on and off to serial line signal from the PC, can be switched from the device with one of the
processor output ports.
8/9. Charging circuit
Found here are:
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The charge control circuit (U11), which enables or disables quick charge based on battery pack voltage and
temperature. The processor can also enable / reset quick charge with the CHRG RESET signal.
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The drip charge performing continuous operation resistance (R185).
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The switching power supply ensuring the 1.25A current required for quick charge.
Connections on the board:
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+15V input (J1) with protection and EMC filtering.
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Battery connection (J4) with protection fuse.
9/9. Printer interface
The bytes providing the pixels to be burnt arrive on the printer head in serial originating from the U46, while their
clock signals originate from the U45 IC. The U46 IC connects directly to the processor bus.