Tektronix 371B, Service Manual

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Maintenance
371B Service Manual
4-27
A28 and A29 Graticule Illumination Lamp Boards.
Perform the following to remove
and install the A28 and A29 Graticule Illumination Lamp boards.
1. Remove the top panel from the 371B.
2. Remove the CRT bezel cover from the lower side of the CRT bezel by
pulling it off with your fingernail.
3. Remove the two exposed screws to remove the CRT bezel from front panel.
4. Remove the CRT filter, spacer, and implosion shield from the CRT frame.
5. Remove J280 and/or J290 from the A25 Main Power Supply board.
6. Remove the (internal scale illumination) light reflector, the light reflector
retainer, and the retainer spring by pulling them out from alongside the CRT
faceplate.
7. Remove the A28 and A29 Graticule Illumination boards by removing the
two screws that secure each board to the light assembly.
8. Replace the A28 and A29 Graticule Illumination Lamp boards in the reverse
order of removal.
LowĆVoltage Power Supply Transformer.
The Low-Voltage Power Supply
transformer is located under the A25 Main Power Supply board. Perform the
following to remove and install the Low Voltage Power Supply Transformer.
1. Remove the top and rear panels.
2. Remove the A25 main Power Supply board as previously described.
3. Disconnect J274 from the A27 Primary board.
4. Remove the four screws that secure the transformer to the floor of the main
unit.
5. Lift the transformer from the main unit.
6. Replace the Low Voltage Transformer in the reverse order of removal.
Cooling Fan.
Perform the following to remove and install the Cooling Fan.
1. Remove the rear panel from the 371B.
2. Remove the protective cover over the A27 Primary board by crimping the tip
of the plastic standoff and pulling the cover from board.
3. To aid re-assembly, note how the fan is placed on the rear panel. The fan AC
connector is located close to the center of the rear panel.