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Tandy TRS-80 Model 4D Service Manual Addendum

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The Addendum to the Model 4 and Model 4 Gate Array Service Manual (Cat. No. 26-1067/8/9) for Model 4D (Cat. No. 26-1070) is Tandy's 1985 service supplement for the TRS-80 Model 4D. The hosted scan has 160 pages: a short Tandy section listing the 4D's differences, followed by TEC's service manual for the FB-500 series drives fitted to the 4D and a manufacturer's parts list for the drive assembly.[1]

Contents

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  • Tandy introduction (PDF page 5): the Model 4 and 4D are the same apart from the drive mount, the drive and its cable, and the keyboard, whose Backspace key does the same as the left arrow. TEC's manual takes the place of Section V (drives) of the Model 4 and Model 4 Gate Array Service Manual.[1]
  • Parts list differences (PDF page 6): keyboard 8790555, drive mount 8729547, drive cable 8709629, drive assembly 8790133; on the gate array board, C2 47 pF and C20 33 pF.[1]
  • TEC FB-500 Series Service Manual, document E0-2129-G, revised December 1984:[2]
    • Chapter 1, mechanical section: clamp mechanism, removal and fitting of the board, clamp, carrier, stepper motor, spindle motor and interrupter, adjustments (motor speed, head radial alignment, track 00, index sensor, head azimuth, head output, VR1, tester checks, steel band tension) and head cleaning
    • Chapter 2, electrical section: block diagram, circuit description and interface signals
    • Circuit diagrams, troubleshooting, parts lists, recommended spare parts and special maintenance tools
    • Reference specification for the FB-501 to FB-504
  • A&A Japan whole parts list for drive assembly 8790133, dated 5 August 1985, 13 pages (PDF pages 111-123).[3]

What this document does not contain

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  • The Model 4 and Model 4 Gate Array Service Manual that the addendum supplements, with the gate array board parts list, was not found online. For the gate array board, see the theory in the 26-2119 technical reference manual and the Sams Computerfacts CS13.[1]
  • Nothing on the power supply or monitor, which are unchanged from the gate array Model 4.[1]

Pages that cite this document

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Download: Tandy TRS-80 Model 4D Service Manual Addendum (26-1070, 1985).pdf

References

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  1. ↑ 1.0 1.1 1.2 1.3 1.4 Tandy Corporation, Addendum to the Model 4 and Model 4 Gate Array Service Manual (Cat. No. 26-1067/8/9) for Model 4D (Cat. No. 26-1070), 1985, hosted as File:Tandy TRS-80 Model 4D Service Manual Addendum (26-1070, 1985).pdf; title, copyright page and introduction.
  2. ↑ TEC (Tokyo Electric Co., Ltd.), FB-500 Series Service Manual, document E0-2129-G, in the addendum; contents pages.
  3. ↑ A&A Japan Ltd., Whole Parts List for catalogue no. 8790133, in the addendum.


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