February/March 1980, Issue 6

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N2   Documentation Errata

Nascom Engineering have forwarded a list of errata for the Nascom 2 manual which they have asked us to publish: so here goes.

“Nascom 2 construction manual

page 5para 7 The diagram ‘component representation’ shows the + at the wrong end of the diode symbol.
page 6para 8 TR1 and TR2 are PNP and not NPN; TR4 is shown inverted in the fourth column of diagrams.
page 10para B4 IC9 should be N2DB PROM; IC17 should be IC16
para C1 IC25 should be ‘81LS97 or 95/97’
para B5 delete ‘causes’; insert ‘may cause’.
Page 11para H1 TP4 and TP5 are inactive at this stage, though the stated signals are available from them during normal operation.”

“Nascom 2 circuit diagram

1) The drawing number, 4-022-103, is to be deleted and replaced with 022-401 (sheet 1 of 5), 022-402 (sheet 2 of 5), 022-403 (sheet 4 of 5), 022-404 (sheet 4 of 5), and 022-405 (sheet 5 of 5).”

(Editors note: we think they mean ‘sheet 3 of 5’ for drawing 022-403; they didn’t tell us where you get the drawings from.)

“2) (022-401) TR1 should be shown as a PNP common collector stage with R14 connected to the emitter and collector grounded.
3) (022-402) TR2 should be shown as a PNP common emitter stage, with R36 connected to the collector and the emitter connected to +12 volts.
4) (022-404) The capacitor C25 on pin 5 of the UHF modulator should be marked DC53.
Pin 15 of IC65 is connected to pin 2 ) of ICGS and not
Pin 10 of IC65 is connected to pin 11 ) as shown. Ed.
5) (029-801) IC19/12 is connected to IC5/11 and IC9/11 is connected to IC5/9.”

“Nascom 2 Hardware manual

page 15 1st item in the test point list should read ‘TP1 300Hz from IC31/3’.
page 20note 5 Switch positions are reversed.
page 20C9 Is as stated and not a tantelum capacitor as mentioned in the construction notes.
C14 Is as listed and not a ceramic as stated elsewhere.
C19 Is a tantelum capacitor though this is not mentioned.
C29 ditto

DC45 & DC52 are as stated and not tantelum capacitors as stated elsewhere.

page 31IC2 should be marked 74LS257 and not 74LS32.
page 35IC58 Is shown as a 74LS163, should be 74LS123.
Note: Difficulty has been reported in identification of certain capacitors. Though it is not possible to guarantee that all manufacturers follow this convention, it is suggested that capacitors marked 102 be regarded as 1n and those marked 100 as 100p unless there are obvious signs to the contrary (size, or the possession of a positive lead).

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