Service Manual Miditron
®
Junior
II
/ ID 1997491 / MJ / 1.0 - June 1998 / Page 117
13. Troubleshooting
The instrument contains software control functions which
test the electronic hardware and peripherals after being
switched on or after stand-by and which detect occuring
errors during measurement. According to the importance of
the error the just measured results are dismissed or in case
of non-repairable errors (Major Error) the instrument
changes to error condition. An error report is announced, in
any case.
Occuring erros have been divided into 3 groups:
- error at self-test
- repairable errors during normal mode
- non-repairable errors during normal mode (Major Error)
13.1
Error at self-test
When starting the program, a hardware self-test is initiated.
The following components are tested one after another:
- ROM
- EEPROM
- RAM
- Frequency Factor
- RTC
- Display
- Light Barrier
- Printer
All errors lead to a system stop with the exception of light
barrier and printer. The occured error is shown on the
display, on the serial interface and printed via a 3-digit
figure. The system stop allows a result printout via the
<Reprint> key and a status protocol is printed.
The ROM-test creates a checksum of the total ROM and
compares it to the saved value.
The EEPROM-test checks the data necessary for the
operation of the instrument and its CRCs.
The RAM-test marks all memory cells with OOh, AAh, 55h
and FFh and checks them. The RAM-test does not erase
any information which meand the data is reproduced after
the test.
The LEDs and frequency factor are tested by initiating a 1
MHz bar and conducting a normal measurement cycle.
(Major Errors)
