Circuit Descriptions - HP PageWriter XL M1705B Service Manual

Circuit Descriptions
The major subassemblies for all cardiograph models are the patient
module, the CPU assembly (which includes the power supply), the
keyboard and LCD display, the printer, and the disk drive (M1700A
and M1701A only). The M1700A also has an optional display that
the operator can use to preview the ECG.
The CPU assembly is the same for all cardiographs except that the
M1700A CPU assembly has extra RAM to accommodate the ECG
interpretation and analysis software. The M1701A and M1702A CPU
Assemblies are identical, except for the ROM. The subassemblies,
including the CPU assembly and its major circuit groups, are shown
in Figure 5-2.
5-4 Theory of Operation