The Flexible Disc Unit consists of the following major assemblies: front panel, back panel, two disc drives, the +5 Vdc and +24 Vdc power supplies, and the Flexible Disc Controller (circuit board). Removing the power supplies requires an almost complete disassembly of the Flexible Disc Unit; thus, power supply removal is the only disassembly procedure included here.
NOTE
The power supply modules (+5.0 Vdc and +24 Vdc) are listed in the Replaceable Electrical Parts list as one number for each power supply. Component part numbers are not furnished. Complete assembly replacement is recommended.
Both the +5 Vdc and +24 Vdc power supplies are fastened together; if either supply is to be serviced or replaced, both supply modules must be removed from the Flexible Disc Unit.
Replacement or removal of the power supplies requires that all major assemblies except the Controller be removed from the Flexible Disc Unit. The following paragraphs describe the procedure for servicing or replacing a power supply.
1. REMOVAL OF POWER SUPPLIES I
WARNING'Before the Flexible Disc Unit is disassembled, make sure that the primary power cord has been disconnected from the pack panel.
a. Remove the three screws on each side of the Flexible Disc Unit. Lift the top cover off the mainframe.
b. Close and latch the covers on both Disc Drives (O and 1).
c. Remove the four screws in the front cover. Disconnect connector J4 of the main power switch cable. Remove front cover and set aside.
d. Removethe six screws in therear support bracket: two screws inthe disc drives, two screws in the power supply mounti ng frame, and one screw in each end of the rear support bracket through left and right sides of the mainframe. Remove the rear support bracket and set aside. Remove the screen cover for the power supply.
e. Remove the screw in the front support bracket through the left side of the mainframe.
Remove the four screws in the disc drives through the front support bracket.
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Maintenance-8002A: Flexible Disc Unit Service
f. The two Disc Drives are attached to a mounting plate that is secured to the mainframe.
Removethe six screws inthe mounting plate: three screws onthe left side of the mainframe and three screws along right side of mounting plate into bottom of the mainframe.
g. Slide both disc drives about four inches out the front of the unit.
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Only the left side of the front support bracket was loosened in Step 1 e; therefore, the disc drives must be carefully pulled out of the unit. When pulling the drives out, observe the connecting cable lengths in the rear of the drives; do not pull further than four inches at this time.
h. Disconnect disc drive power connectors P2 and P3. Disconnectthetwo in-line ribbon cable connectors, one on each disc drive. The disc drives are now free to slide out of the Flexible Disc Unit.
NOTE
To remove a disc drive or to separate the two disc drives for servicing, remove the four screws that attach each disc drive to the mounting plate.
i. Remove the eight screws holding the back panel to the mainframe: six screws through the back panel and one screw in each end ofthetop motor support bracketthroughthe left and right sides of the mainframe.
j. Tiltthetopofthe backpanel awayfrom the mainframe and disconnect P1. Then remove the four screws attaching the drive expansion plate to the back panel.
k. Free the wires and cabling attached to edge connectors P1, P2, P3, and P4 within the unit.
Now remove the back panel and set aside.
I. Disconnect connector P5 onthe Flexible Disc Controller. Remove the six screws that secure the power supply mounting frame to the mainframe.
m. Remove the power supply mounting frame (containing both power supplies) from the Flexible Disc Unit. Place the supply mounting frame on a flat work surface.
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Maintenance-8002A: Flexible Disc Unit Service
2. REPLACING DEFECTIVE POWER SUPPLY
If only one of the power supplies is defective, only the defective supply must be replaced. The following replacement procedure is the same for either power supply.
The fol/owing procedure requires you to unsolder and remove existing wires on the defective power supply and to reconnect and solder these wires to the replacement power supply. Use extreme care to make sure that the existing wires are not damaged and that the wires are reconnected to their correct terminals.
a. Locate primary winding termination numbers 1 through 4 on the power transformer. For each of these four terminations, cut the protective tubing from the wire and transformer terminal. Unsolder the four terminations and remove the wires. Make sure each wire is tagged as the wires are removed.
NOTE
Only the primary winding terminations are disconnected on the power transformer.
The secondary windings are connected internally.
b. Unsolder and remove the output wires. Make sure all wires are tagged.
c. Remove the mounti ng screws for the defective power supply and separate it from the mountingframe. Using existing mounting brackets, attach the replacement power supply to the mounti ng frame.
d. Before reconnecting the wires, slip heat-shrink tubing (or similar tubing) over the primary wires; then reconnect and solderthewires removed in Step 2, parts a and btotheterminals of the replacement power supply module. Heat and shrink the tubing over the wires and terminals after soldering. Cover as much of the transformer connecting lugs as possible before shrinking the tubing.
3. REPLACEMENT OF POWER SUPPLIES
TO,replace the power supply mounting frame in the Flexible Disc Unit, reverse the procedures listed above under "Removal of Power Supplies".
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8002A: Flexible Disc Unit Service
Section 5 REPLACEABLE ELECTRICAL PARTS
PARTS ORDERING INFORMATION
Replacement parts are available from orthrough your local Tektronix, Inc. Field Office or repre~entative.
Changes to Tektronix instruments are sometimes made to accommodate improved components as they become available, and to give you the benefit of the latest circuit improvements developed in our engineering department. It is therefore important, when ordering parts, to include the following information in your order: Part number, instrument type or number, serial number, and modification number if applicable.
If a part you have ordered has been replaced with a new or improved part, your local Tektronix, Inc. Field Office or representative will contact you concerning any change in part number.
Change information, if any, is located at the rear of this manual.
SPECIAL NOTES AND SYMBOLS
XOOO Part first added at this serial number OOX Part removed after this serial number
ITEM NAME
In the Parts List, an Item Name is separated from the description by a colon (:).
Because of space limitations, an Item Name may sometimes appear as incomplete. For further Item Name identification, the U.S. Federal Cataloging Handbook H6-1 can be utilized where possible.
ABBREVIATIONS
ACTR ACTUATOR PLSTC PLASTIC
ASSY ASSEMBLY QTZ QUARTZ
CAP CAPACITOR RECP RECEPTACLE
CER CERAMIC RES RESISTOR
CKT CIRCUIT RF RADIO FREQUENCY
COMP COMPOSITION SEL SELECTED
CONN CONNECTOR SEMICOND SEMICONDUCTOR
ELCTLT ELECTROL YTIC SENS SENSITIVE
ELEC ELECTRICAL VAR VARIABLE
INCAND INCANDESCENT WW WIREWOUND
LED LIGHT EMITT.JNG DIODE XFMR TRANSFORMER
NONWIR NON WIREWOUND XTAL CRYSTAL
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Replaceable Electrical Parts-8002A: Flexible Disc Unit Service