Service manual M695 | Description of control unit MEL64/65 |
Doc code 636 718 | 09/93 |
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5V supply Receiver boardPGND, SENS and logics groundSENS
An LED on the function display shows 5V OK. The following are supplied with power: Handswitch or f&switch, and logics on receiver board.
Microscope ground (PGND) and SENS are connected in the microscope. The high lamp current produces a voltage drop of about 0.6V at PGND. This voltage is passed to the control unit through SENS.
For the reason indicated above, Logic ground is about 0.6V below PGND in the microscope. The voltage drop at PGND influences the level of the control signals.
All control signals to the microscope are measured with the testbox in relation to SENS. SENS is connected to GND trough a