Manual

8 Troubleshooting – Messages – Maintenance

780/781 pH/Ion Meter, Manual

125

RAM Test

This test checks the condition of the instrument memory without altering

its contents. A successful test is concluded with the message '

ram

test ok

AD-Converter Test

The electronic components of the analog-digital converter are checked.

At the end the two messages '

ADC EEPROM Test ok' and 'ADC Int.

ok x mS

' should appear. Instead of 'x' the message should contain a

number between 15.0 and 25.0.

LCD Display Test

With this test you can check that the LCD display is functioning proper-

ly. It consists of a sequence of individual tests which can be switched

forward with

<QUIT>

. The test can be halted with

<ENTER>

and can-

celed with

<MODE>

Key Test

The correct functions of all the instrument keys can be checked here.

After the start a 3-fold beep will be heard (so that you can also test this

straight away) after which the instrument will respond to the pressing of

each key by displaying the corresponding key code. However, the

key will still switch off the pH/Ion Meter. This test is termi-

nated by pressing the

<CLEAR>

key twice.