R&S ZVA8 - Page 363

R&S ZVA Repairs
1177.5333.02 3.55 E-11
Risk of damage
When disconnecting cables, be especially careful with the cable to the keyboard. It is a
foil cable and can only be removed when the locking device on the foil-cable connector
is released.
 Remove the front module controller (for instructions see “Replacing Front Module Controller A90“)
 Place the instrument on its top and remove the instrument’s base cover (297) by undoing the
screws (299).
 Undo the RF cabling from the reflectometers (165, 170, 175) to the LO divider (125) and to the
motherboard.
 Release the 50-pin flat cable and disconnect from the reflectometers.
 Remove screws (151, 156, 161) and take out the reflectometers.
 Undo RF cabling at the LO divider (125).
 Disconnect the 12-pin flat cable from the LO divider
 Remove screws (127) (2 in the strut, 4 in the rear panel) and take out the LO divider together with
plate (126)
Undo the screws holding the connectors on the rear panel:
 The 6 hexagonal nuts and washers for the BNC connectors.
 2 hexagonal bolts (530, 540) each for the monitor interface and the user-control interface.
 2 hexagonal screws (550) each for the USB interface and in the dummy panel (555).
 Remove the 3 screws (144) each for the left and right side panels and the 2 screws (143) in the
center and take out both motherboard rails (140, 141).
 Disconnect any cabling still on the motherboard (fan, floppy, IEC-bus, etc.).
 Remove the 14 screws holding the motherboard (520) and take out the motherboard.
 Remove the RF and IF cables using the tool 11W 101-000 (Rosenberger).
Installing the motherboard and reassembling the instrument
N.B.: The motherboard is the passport of the instrument and unique for every unit.
The Eprom on the motherboard contains the serial No. of the instrument.
Pre-configured motherboards are not available.
 Install the new motherboard by reversing the removal procedure.
N.B.: Install the motherboard carefully to prevent any damage to components.
Lettering indicates where cables are to be connected.
 Reinstall the front module controller, front unit, power supply, boards and cables, instrument covers,
enclosure and rear-panel feet by reversing the disassembly procedure.
 Connect the mains cable, turn on at the mains switch and press the ON key.
 For writing motherboard data to the EPROM please contact the Service Center in Memmingen.
 Select Service Level 2 (see Service Functions).
 Check the protocol file for errors: [ INFO : Error Log ]