Heathkit H9 Manual page 44

Pase4.
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CONDITION
POSSIBLE CAUSE
73. No plot.
1. Plot key not pushed in.
2.
No plot coincidence. 1C206, lC209A, lC209B, lCzOgD,1C212,
tc219A.
3. Plot video. lC210B, lC208A, lC218A.
4.
t c zz l B , tc 22 1?.
74. Plot line appears in wrong place.
1.
2.
Plot coincidence. 1C206, lC209A, lC209B, lC209D.
Plot inverters. 1C212, lC219A.
75. No repeat (characters or cursor).
1. 1 901 .
2. Vn' input to keyboard open
3. D 4 01.
4. Repeat Key.
76. No cursor reoeat.
1 . D 40 1.
2-
Q 401 .
3. R403.
77. No relresh interrupt.
1. No refresh interrupt signal. lC610C, P601-21, 5703-3.
2.
Rear panel Baud switch not wired correctlv for > 600 baud.
3. tc705A, tc706B.
78. Screen blinks at low baud rates.
1.
Rear panel Baud switch wired for > 600 baud
2. tc705A.
79. No hold screen mode.
1. tc733c. rC733D. tC739A
80. Locks uo in hold screen mode. 1. tc739B. tC739D. tC739A. tC739C
81. No transmit page.
1. XP flip-flop not being set. lC731C, lC731D, lC732C,lC732D.
2. 7C oulse.
3. No OB2XP load pulse. lC701A, lC701B, lC704A, 1C702. No
OB2 pulse into 1C702.
4. Count up not happening:
Duplex key in Full Duplex (pushed in) instead of Half
Duplex (released).
1c704.
tC725A, lC719C (fake DAV).
82. Transmit page won't stoo.
1. lc7259. lC721A.
2.
Transmit page was started in the hold screen mode. Press and
release the Scroll or Break keys to exit the transmit page mode.
83. No end of line bell.
1.
End of line decoder. lC7168. lC716C. lC718A. lC735C.
2. Monostable 1C736, R717, C7'17.
3. Speaker driver lC742A.
84. No bell from control G.
1. Bell detector on the l/O circuit board. lC617D, 1C614, 1C623.
2.
tc724B.
3. Monoslable 1C736, R717, C717.
4.
Speaker driver lC742A.
85. Screen is not erased when the Terminal is lurned on.
1. Power up reset. Q701 , lC717A, lC717B, lC717C, lC717D,
lc717E, D701 .
2.
Erase circuit. lC715A. lC723A.
86. Cursor is moving when the Terminal is turned on.
'1 .
Terminal is in transmit page mode.
2. XP flip{lop (1C731C, lC731D) did not get reset by the power up
reset.