Tektronix 1705A, Instruction Manual

Page: 130 / 223

Maintenance
1705A Spectrum Monitor
6- 5
selected by moving the cursor to a point adjacent to the test name and pushing
the INPUT push button.
USE SPAN KEYS TO MOVE CURSOR,
PRESS INPUT KEY TO SELECT
TEST
MEMORY
>DAC
LED
KEY
EXIT
Figure 6-2: 1705A Test menu, displayed when Test is the Main menu selection
The NOVRAM (Non Volatile Random Access Memory) test is selected from the
crt-displayed Test menu by pushing the VIDEO push button. When this test is
selected, the crt first displays a message that gives the memory version and
copyright dates.
The test then proceeds to check the NOVRAM and the Electrically Eraseable
Programmable Memory (EEPROM). The test goes through three steps, each
with its own message displayed on the crt starting with:
NONVOLATILE <2444> RAM TEST
Its first action is to write to and read out of memory; during this step there is a
message that the microprocessor is:
WRITING AND READING 2444
This test checks that all lines and the NOVRAM are operating correctly. If the
microprocessor can not establish Read and Write communications with the
NOVRAM (U812), the following message will be displayed on the crt:
ERROR : CANNOT WRITE TO 2444
Memory Test