Service Cautions - Sharp CE-129P Service Manual

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C E-l29P
7. PCU (SC6994) SIGNAL DESCRIPTION -
Pin No. Signal Name
1
SEL2
2
SEl1
3 VOO
4 ACl
5
BUSY
RIW
6
7-10 04-1
11
STP
12
S
13 24
14 10F
15 H7
16 H6
17 GNO
18-22 H5-H1
R
23
24 PD
25 T
26-28 TSl-3
29 VP1
30-32 BCl-3
33 CCK
34
l:fA
35 HB
36 HC
37,38 Cl1,2
39
PF
40 NP
41 ACL
42 OP3
43 OP2
44 OPl

8. SERVICE CAUTIONS

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Cautions in exchanging the printer unit
In order 10 prevent print density
thermal head resistance variation, the printhead is classified
into three ranks of A, B, and C, and the rank is indicated
on the reverse side of the printer u~it F.P .C. After exchange
of the printer unit, relevant circuit change must be observed
in accordance with the procedure mentioned below.
In/Out
Select
In
In Select
Power supply
Out
Notused
In Histl: chip select
In Hi!#l: read
Dm input
In
Notused
Dm transfer mode select Une
In
Hi!#l: serial input
In Print digit select Une
Hi!#l: 24 digits (GNO connected)
Out Printer motor drive signal
Out Printhead element on pulse
Out Printhead element on pulse
Power supply
In
Out Printhead element on pulse
Printer reset (printhead home position detect)
In
Power down (in supply during printer operating cycle, otherwise,
Out
power is not supplied to the printer drive circuit.
Printer timing (generated from the tachogenerator
In
Test pins
In
Printer control circuit supply power
Out
PCU
ln/Out frequency controI
Out Clock test pin
In
Notused
In
Basic clock pulse control resistor fitting pin
In
Paper feed key input
In
GNO Connected
In
All elear input
In
ACl select (high when on)
Out
Not used.
Notused.
I
variation causecl by
-4-
Do not sale !
Oescription
- - - - - - - - - Low: Non~lect
Hi!#l to low transition:
- - - - - - - - low: parallel input/output
Low: 16 digits
(Print density adjust pin._.JA and JB pin connection
varies according to the printhead rank).
Short JA when the rank A printer is used.
Leave all open when the rank B printer is used.
Shrt JC when the rank C printer is used.
Table· 1
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,
write
of the motor)
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,
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