ml280 - troubleshooting
DESCRIPTION
Oki ML280 - Troubleshooting GuideTRANSCRIPT
MICROLINE. 280TROUBLESHOOTING MANUAL
WithCOMPONENT PARTS LIST
PREFACEThis manual describes the component level troubleshooting and repair process for the Ml280.
TROUBLESHOOTING MANUAL
CONTENTS
1. Outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l - l
2. Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l - l
3. Troubleshooting Procedure ............................................... l-2
4. Troubleshooting Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1 Outline
Gelleral
This troubleshooting manual is designed to locate and repair problems
on a component level for the INDU-printed-circuit boards and other
printer components.
1.1 Remarks
This manual requires basic knowledge of electronic circuits.
.
\-.
.
Use chip-dedicated soldering irons (such as Ungar soldering irons)
since the printed-circuit boards of the ML280 have heat-destructible
components (chips, packages, etc.). (Soldering irons for flat packages
are widely available.)
Be careful not to break any wiring etched trace patterns on the
printed-circuit boards while replacing components.
2 TOOlS
In addition to the tools listed in the printer's Maintenance manual,
the following tools are required for repair of components on the
printed-circuit boards:
. Extension cord (OKI Part No. 3YU5003-5010Gl or equivalent)
a Oscilloscope
. Soldering iron (with fine tip) ’ commercially available
l Solder wick I
l-l
3 Troubleshoot ing Procedure
Troublesboot by thegeneral flowchart Note 2
Sqmir tile failureaccordInS to theassociated repairf 1owc,,nrt
Run ebe printer for ap r e d e t e r m i n e d t i m ewithout stopping.
N o t e s 1: Visually check the defective printed-circuit board before
mounting it on the printer.
2: If the printer or the printed-circuit board is returned along
with an error report, first check the reported failure.
l-2
4 Troubleshooting Flowchart
4.1 General Flowchart
1-3
I I
Note: PITCH and MODE switches are valid during select and deselect states.
?-,
1-4
1-5
1 NO
1-6
Note: This step is required since parts are overloaded if powerrepeatedly suppl ied wi th the de fec t ive dr iver parts .
1 -7
Replace MD” Replace TR3
bvnt collector Of Replace TR4
J
1-8
When power is turned on, Fuse (Fl) on the INDU board blows.
No
the proper ly ratedf u s e i n s t a l l e d ? I
Replace with a properlyrated fuse .(1.5 A)
Measure the resistanceb e t w e e n +8 V line andgrmuld.
Measure Ck resistancebatween +5 V l ine andground.
I
Replace the REG andTR14
l-9
2. Power supply circuit
02-I AC circuit and rransforner
_I
l-10
DC +30 " circuit
Check and replacediodes D8.D9,DlOand Dll if faulty
I
l-11
3. p CPU circuit
2: The level of each of the output signals should not be at halflevel (about 2 to 3 V).
1-12
4. SP motor drive circuit
Paulty homing operation
I
Replace TR3,HKJV and QL
Note: The phase of the line-feed motor is adjusted when a space-homing ismade at power on. Turn on the POWER switch while touching theplaten knob. When you feel the platen knob rotate, the CPU circuitis normal.
1-13
Replace the MTDV.
NO
IR e p l a c e TR6,Ll
Replace thc.SP Notor.
1-14
Notes 1 : MTDV operation:
SPD-A pulse signal from the MTDV-6
through buffer 1 and comparator 2,
switching c ircui t (TR3, Ll, D6 and
is output to the MTDV-2
smoothed by the choppier
U), then led as a
phase-driving voltage to the MTDV-1.
2 : Coil current protector
When a current flows through a phase, voltage drop at resistor
R7 is generated by current i . If the voltage drop becomes higher
than the voltage at the MTDV-4, the limiter 3 and buffer 1 are
powered off . Thus, the MTDV is powered off.
3 : Voltage protector. If the voltage generated in the chopper
switching circuit exceeds 30 V, comparator 2 is powered off.
I Remove paper. I
1-16
Turn the Power switchon.
1 - 17
PITCH L a m p 10 or 12 or 17 does not l ight
Turn the power s w i t c h0 ” .
Check connector connection.Replace Lamp 10,
TR3 (SLSX b o a r d ) ,92 (SLSX b o a r d ) , a n dQ4 (INDU board) .
Depress PITCH s w i t c h .
NOI s L a m p 1 2 o n ?eY e s
Check connector connection.Replace Lamp 1 2 ,
Q, (SLSX b o a r d ) ,Q 2 (SLSX board) ,Ql (SLSX b o a r d ) , a n dQ4 (INDU board).
C h e c k c o n n e c t o r c o n n e c t i o n .Replace Lamp 17.
Q 3 GLSX board) ,Q2 (SLSX b o a r d ) ,Ql (SLSX b o a r d ) , a n dQ 4 (INDU board) .
-\ !
-4
I EndI
O(5-5 NODE Lamp NLQ or UTILITY or “SD does not light
I
NO
Check ConneCtor connection.Replace UTILITY Lap,
Q3 (SLSX board) ,Q2 (SLSX b o a r d ) , a n dQ4 (INDU b o a r d ) .
Depress NODE switch.
I EndI
1 - 19
6. Switch circuit
suitdl does not operateI
-1
l-20
7. Line feed mator circuit
O(7-l Does no? perform line feed operation
I
Replace TR&, ~~13 .
L
LF Timing chart
,'
1-21
Note: Measure the resistance of each printhead, it should be about ZOQ._I
1-22
i-- O(8-2 some dots are not printed.
.-
Note:
1-23
Head ON
Head 1 to 9 X X' _IQ7-6Threshold
level
I
47-l I I I I I 1TR502-C
Head drivecurrent
1-24
9. Interface (Receiving)
O(9-1 Does not print at all.
I
Replace 94 or 93.
1-25
1 - 2 6
I II
l-27
1 0 . SASF o p e r a t i o n
O(10 Paper does not f e e d to print position (SASF functfon).
Turn off !xwer. remove INDU board, openbail arm, and measure the resistance betweenconnection board pins 20 and 24,
resistance 0
II
Replace INDU board.
1 - 2 8
COMPONENT PARTS LIST
Drawing List
INDU-Printed Circuit Board 4YA4050-2881Gxxx _. _. _. l - l
0
(
INDU-Printed Circuit Board with ROM 4YA4050-2881G3 (IBM) 1-5
l INDU-Printed Circuit Board without ROM 4YA4050-2881Gll ____________..__ 1 - 1 3
SLSX-Printed Circuit Board 4YA4050-2155Gl _____________._._ 1 - 2 1
SLPB-2.3 Printed Circuit Board 3YU5003-5611GZlG3 _. _. 1-25
._
ROM identification Chart by G No.
GNo. 1 ROM-No. 1 ROM Dart No. ROM Label t ADDlicatiOn 1 Remarks 1
GO03 1 08 1 4YR4067-7145Gl 1 67-7145 I For INDU I IBM I
.-
Figure 1 INDU-Printed Circuit Board (4YA4050-2881Gxxx) l/2 (l/2)
l-1