Service manual

Service Manual
Note the correct position of the ROMs in their sockets;
ROM pin 1 is two rows down from the 'top' of the socket.
Fitting the test ROMs in place of the RISC OS
ROMs
Providing that the ARM, memory controller and video
controller are functioning, the test ROMs will auto-boot
into the menu-driven display shown in Fig 5-4 Test ROM
display menu. At any point in the operation of the test
ROMs, pressing the BREAK key or re-powering the
machine will re-start the program and re-display the
menu.
Main memory test
The memory test checks memory according to memory
size selected.
It is possible that faulty memory may lie in the region
designated as screen memory. If this occurs, the video
display may become unreadable. For this reason, the
Fig 5-4 Test ROM display menu
5-24 Issue 2, June 1991 Part 5 - Main PCB fault diagnosis