22
Subject to change without notice
H M 3 0 3 - 6 T r o u b l e s h o o t i n g
1.3. Set the front face of the oscilloscope on a soft surface and
pull the cabinet off. (Photo 1.7, 1.8 and 1.9)
STOP
Please note:
After repair work, close the instrument in reverse
order of above.
2 Preliminary Tests
The precondition for undistorted operation is correct supply
voltages generated by the power supply. It is highly recom-
mended to check the power supply output voltages before any
other action.
The following steps show you what to do.
2.1 Miscellaneous voltages
Locate and identify a Molex 8 pole connector J1002 (at the inner
side of the vertical rear chassis) where an 8 pole ribbon cable
coming from the MB board is connected. See photo 2.1.
All voltages are measured with respect to ground (chassis).
The following voltages must be present:
Pin 1: approx. +175 V
Pin 2: +146 V (± 0.5 V)
Pin 4: approx. +5.2 V
Pin 6: +12 V (± 50 mV)
Pin 8: approx. -6 V
1.7
1.8
1.9
2.1
