BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...

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BBC Microcomputer service manual SECTION 1 BBC Microcomputer Models A and B (ANA01 - ANB04) SECTION 2 BBC Microcomputer Model B+ (ANB51 - ANB54) SECTION 3 Additional Upgrades 1770 Disc interface daughter board upgrade 64K Sideways RAM upgrade Part No. 0433,001 Issue 1 October 1985
Page 4 and 5: Within this publication the term 'B
Page 7 and 8: BBC Microcomputer Service Manual Co
Page 9: WARNING: THE COMPUTER MUST BE EARTH
Page 12 and 13: * An interrupt driven elapsed time
Page 14 and 15: 1.2.3 Expansion The following expan
Page 16 and 17: 2 General Description of Hardware 2
Page 18 and 19: There are two 6522 versatile interf
Page 20: A 555 timer circuit (IC16) provides
Page 23 and 24: The 6502 microprocessor runs from a
Page 25 and 26: The video processor contains a piec
Page 27 and 28: Since there is only 32 Kbytes of RA
Page 29 and 30: 3.4 RGB + PAL encoder + UHF output
Page 31 and 32: 3.6 Internal VIA One 6522 VIA devic
Page 33 and 34: 3.12 Econet ICs 89 to 96 are concer
Page 35 and 36: 4 Upgrading the PCB In these instru
Page 37 and 38: ix) On issue 1 circuit boards only,
Page 39 and 40: iv) If the MOS ROM version 0.1 is f
Page 41 and 42: 5 Selection links and circuit chang
Page 43 and 44: 19. WEST forces slow access to ROMs
Page 45 and 46: 5.2 Table of link options. The foll
Page 47 and 48: 7. A resistor (R171) was connected
Page 49 and 50: 6.3 Fault Isolation Having checked
Page 51 and 52: 6.4 Most Common Faults In the follo
Page 53 and 54:
* Certain other faults on the VDU d
Page 55 and 56:
The following shows pin 24 of the d
Page 57 and 58:
6.5.2 Test ROM The listing shown be
Page 59 and 60:
770 ENDPROC 780 790 DEFPROC_RNW_exe
Page 61 and 62:
10 REM Dumb Terminal Program 20 REM
Page 63 and 64:
The analogue input is on a 15-way D
Page 65 and 66:
7.3 Hardware Hints and Tips Here ar
Page 67 and 68:
44 74LS74 206,174 12,1 45 74S139 22
Page 69 and 70:
9 10uF 16V Elec 4,4 10 lOnF Plate c
Page 71 and 72:
56 Not used 57 10R 5,5 58 150R 1,7
Page 73 and 74:
8.6 Links Some links have been omit
Page 75:
9 Appendices 65
Page 92 and 93:
MAIN CIRCUIT BOARD MODEL B + DISC +
Page 94 and 95:
143 742,283 INTEGRATED CIRCUIT 74LS
Page 96:
QWERTY These are the upper left key
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BBC Microcomputer Service Manual Oct 1985 Section 1 BBC Micro ...

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