Download Speco Technologies VM-1201 User's Manual

SERVICE MANUAL
MODEL
：
VM-1201
REVISION
：
A0
DATE
：
MAY. 21. 2001
DOCUMENT NUMBER ：
WARNING
==========
For continuous protection against radiation, shock and flame, replace only with same type
and rating components specified in the approved sheets.
Disclaimer
Speco Technologies makes no representation or warranties, either expressed or implied, with
respect to the contents hereof and specifically disclaims any warranties, merchantability or fitness for any
particular purpose. Furthermore Speco Technologies reserves the right to revise this publication and to
make changes from time to time in contents hereof without obligation to notify any person of such
revision or changes.
Table of Contents
1. INTRODUCTION .......................................................….....……………………………………..
1.1 OPERATIONAL SPECIFICATION ................................…............…………………….……...
1.1.1 Operating Environment ...........................................…..…………………………………..
1.1.2 Signal Input Requirements ...................................….....…………………….…………….
1.1.3 Power Input Requirements ................................…......……………………....……………
1.2 FUNCTIONAL SPECIFICATION...........................…....……………………...............……….
1.2.1 Display Quality....................................................………………….………..…………..
1.3 CONTROL AND ADJUSTMENTS.........................…....................…………………………...
1.4 PHYSICAL SPECIFICATIONS................................….........……………………......………...
3
3
3
4
4
5
5
6
7
2.THEORY OF OPERATION..........................................…..…………………….........…………..
2.1 MAIN POWER SUPPLY BLOCK......................….....….……………………...............……...
2.2 VIDEO INPUT BLOCK ............……….......................…………………….............………….
2.2.1 Video filter………….….………………………………………………………………….
2.3 VERTICAL & HORIZONTAL PROCESSOR
7
7
7
7
7
2.3.1 Vertical guard……………………………………………………………………………… 7
2.3.2 Vertical Drive Output………..…………………………………………………………….
7
2.3.3 Sync Separator…………………………………………………………………………….
7
2.3.4 Phase Detector…………………………………………………………………………….. 7
2.3.5 Supply……………………………………………………………………………………... 8
2.3.6 Horizontal Oscillator, Horizontal O/P Transistor and Second Phase Detector…………… 8
2.3.7 Mute Output And 50/60 HZ Identification………………………………………………... 8
2.3.8 Sandcastle Output…………………………………………………………………………. 8
1
2.4 VERTICAL DEFLECTION BLOCK.........................................……………………..………...
8
2.5 HORIZONTAL DEFLECTION BLOCK.............................……………………............……...
8
3. TROUBLESHOOTING INSTRUCTIONS............................................……………...…….…..
9
3.1 NO DISPLAY, NO POWER.......................……………………………………………………..
9
3.2 NO DISPLAY, (POWER OK)............…………………………………………………………..
9
3.3 NO DISPLAY, (NO ASTER) ……………………………………………..........……………..
10
3.4 NO PICTURE OR NO COLOR (RASTERK)..................………………………...………….
10
3.5 VERTICAL DEFLECTION FAILURE............................................…………………..………..
10
APPENDIX：
A. SPARE PARTS LIST
B.
SCHEMATICS AND PCB LAYOUT DIAGRAM
2
Audience
This service manual is primarily for system / service engineers, distributors and dealers. It carries the
assumption that the reader understands the basic operating concepts.
Purpose
This manual contains reference data for Speco Technologies monitor. It gives information regarding
the operating principles of monitors, as well as technical service and maintenance information.
1. Introduction
The VM-1201, high performance monochrome monitor, display over 1,000 TV lines resolution on a
bright 12-inch picture tube. This combination provides excellent multi-screen displays commonly
produced by picture-in picture and quad units.
All user controls are conveniently located behind a protective front panel door. This monitor can be
placed on a desk or mounted in a standard 12-inch rack (with an optional rack mount kit)
This series are housed in an enameled steel cabinet for ruggedness and durability, and with the exception
of the picture tube, the circuitry is all solid-state. It also feature video loop through connectors with
switchable high-z/75ohm termination.
The VM-1201 is an excellent choice when you require a rugged, compact B/W monitor. The exquisite
and reliable design of this monitor will provide years of trouble-free operation.
1.1 Operational Specification
1.1.1 Operating Environment
‧
‧
Temperature
Operating
：-10 to + 50℃
Storage
：-20 to +70 ℃
Humidity (Relative)
Operating
：10 to 85% non-condensing
Storage
：10 to 95% non-condensing
3
1.1.2 Signal Input Requirements
‧
Connector
For CVBS：BNC terminal
Type：composite video input
Level：1.0Vp-p
Synchronous：0.3 V
Luminance：0.7V
Polarity：Positive bright
Impedance：75 ohms
1.1.3 Power Input Requirements
‧
Operating Voltage Range：90 ~ 264 VAC at 50 / 60 ±3Hz
‧
Input Current at 90 VAC
Operating：0.5 Amps rms. maximum
‧
Input Current at 264 V
Operating：0.3 Amps rms. maximum
‧
Power consumption
Normal operation：30 Watts maximum
1.2 Functional Specification
The standard conditions for verifying the following specification are as below：
4
• Temperature
：25 ±5℃
• Magnetic field
：No additional magnetic field in near side
• AC line Input
：100 ~ 240 VAC ±10%, 50/60 ±3Hz
• Warm-up Time
：30 minutes min. after power on and signal applied
• Ambient light
：400 to 600 lux.
1.2.1 Display Quality
‧
Display area (monoscope pattern)：full scan
‧
Video Amplifier Performance
‧
‧
Video Bandwidth
：8 MHz
Light output (brightness and contrast at maximum)
‧
At block pattern
：100 FL minimum
‧
At full white pattern
：50 FL minimum
‧
Contrast adjustment range：Over 12 dB
‧
Linearity (cross pattern)
‧
Horizontal ：10% maximum
‧
Vertical
：10% maximum
5
‧
Picture geometry：≦ 2.5%
‧
Picture centering：≦ 6mm
‧
Size stability：Picture luminance from 5 FL to max., the size shall be less than 2.5%
(with full white pattern)
‧
Swing and jitters：Swing and jitters are not allowed (viewed at 50cm from eyes to
screen).
‧
Focus：(viewed at 50cm from eye to screen, contrast adjusted to set luminance at 20 FL
with full white pattern, brightness set at raster just disappeared) Inspect full
character pattern, all characters should be distinguished.
1.3 Controls and adjustments
• External user’s controls：
• Brightness adjustment
• Contrast adjustment
• Horizontal hold
• Vertical hold
• Volume adjustment (optional).
1.4 Physical Specifications
• Dimension：313mm(H) ×310mm(W) x300mm(D)
• Net Weight：9 Kg
2. Theory of Operation
6
This section describes each functional block of the monitor.
2.1 Main Power Supply Block
• AC power input：AC socket
• Line input noise / EMI filtering：Line filter T902 ;
X-Cap C901, C902.
Y-Cap C903, C904, C905.
• Over current protection：Fuse
• Power on/off control：Power switch
• AC to DC conversion and filtering：Diode D901, Capacitor C906
• Start-up circuit：R914, C914.
• Main switching power controller, free run oscillation, voltage feed back, switching duty control,
cycle by cycle over current protection, power MOSFET driving：U901-UC3842
• Free run oscillation：R909, C910.
• Voltage feed back and control：output voltage control R910, R911 & VR901; gain compensation
C911& R903.
• Current sensing and cycle by cycle over current protection：Current sensing R904; Noise
filtering R906, C909.
• Energy storing and transferring：Power transformer T901.
• Power driving：Power MOS transistor Q901.
7
• Snubber circuit：Snubber C907, D902, R902.
• Primary side self-powering circuit：D903,C914.
• Output 13.5 volts for vertical & horizontal drive circuits：D904, C915.
• Output 27.5volts for horizontal deflection circuit：D906 ,C916.
2.2 Video input block
• Signal input buffering and switch
‧
CVBS Input buffer ：Q201 & R201,R202.
• Video filter & output stage.
‧
Video input：Through C202 to W202 (Contrast VR ) and differential amplifier Q202,
Q203.
‧
Video amplifier: Cascade amplifier R219, Q204, Q205, R222, C206.
‧
Brightness control:VR201, R214, R225, R226, Q204.
2.3 Vertical & horizontal processor
2.3.1 Vertical guard:
This vertical feedback signal on pin2 when the level on pin 2 is below 0.35v or high
than 1.85v the guide circuit inserts a continuous level of 2.5V in the sandcastle output
signal of pin 17.The results in the blanking of the picture displayed, thus preventing a
burnt-in horizontal line.
2.3.2 Vertical drive output:
The drive o/p pin1 of U401 delivers a drive current of 1.5mA at 5V output through R302
to U402 pin1.
2.3.3 Sync separator:
The video input through C401, R401 and filter C402 to pin 5 of U401.The Sync separator
is designed such that the slicing level is independent of the amplitude of the Sync pulse. The
8
black level is stored at pin7 by C404. The slicing level is stored at pin6 by C403 and decided
by R403.
2.3.4 Phase detector:
The phase detector circuit is connected to pin8. The circuits are activated depending on
the voltage of pin18 and the state of the Sync pulse noise detection circuit, C405, C406,
R405.
2.3.5 Supply (pin9, 10 and 16):
U401 can start operating by application of a very low supply current into pin16. When the
starting circuit is taken from pin10 via internal diode, and the voltage on pin16 will stabilize
to a typical value of 9.4V
2.3.6 Horizontal oscillator, horizontal output transistor, and second phase detector (pin11, 12,
14 and15):
The oscillator is connected to pin15. An external RC; C409, R412, VR401; sets the
frequency combination between pin15 and ground. The open collect horizontal output is
connected to pin11. The duty factor is set by an internal npn emitter follower stage
connected to pin14. When no flyback pulse is detected at pin12 the duty factor of the
horizontal output stage is set to 50%.
2.3.7 Mute output and 50/60HZ identification (pin13):
Pin13 has the possibility for 50/60HZ identification. A pull-high resistor R408 achieves
the function.
2.3.8 Sandcastle output (pin17):
The sandcastle output pulse generated at pin17.
2.4 Vertical Deflection Block
• Power amplifier：
‧
The DC level across C308 and the current is detected by R306 and feedback to U401
through R311.
‧
The driver output comes from pin5 and it drives the yoke by a negatives slope current ramp
R419 is used to stabilize the power amplifier.
‧
Boost power D301, C305 is connected to pin3.
9
• Flyback generator：
‧
U301 pin6 is the output of the flyback generator that when driven, jumps from low to high
condition C305 transfers the jump to pin3
• Vertical size control：VR301, R312, R308.
2.5 Horizontal Deflection Block
• Horizontal drive buffering：Driving source-U401 pin11. Driving transistor-Q40, to pull high the
driving waveform to drive the Q401(MOS FET).
• Horizontal deflection：Horizontal Output transistor-Q401; Load-Yoke inductance and C414 ;
D401, High Voltage generation-flyback transformer .
3 Troubleshooting Instructions
‧
This chapter describes possible failures of the monitor with corresponding check/correction
actions, and guidelines for safe operation and service of the monitor.
3.1 No Display, No Power
3.1.1 First of all, turn power off, use multimeter to check Q901, and R904, replace if bad. Turn
power on after that.
3.1.2 Check DC voltage across C906. If no voltage or voltage too low, check and fix the following
components：AC receptacle poor contact, fuse F601 broken, power switch malfunction, or
bridge diode D901 bad
3.1.3 Check voltage on U901 pin 7 for start up condition：If voltage on U901 pin 7 reaches the start
up voltage(around 15 to 17.5V), U901 UC3842 will start to work and output 5V at pin 8. If
voltage on U601 pin 7 is too low, check and fix following circuits：start up circuit R914,
and C914.
3.1.4 If no output pulses at U901 pin 6, check and replace U901.
10
3.1.5 If driving pulses at U901 pin6 and drain of Q901 are correct but voltage at U901 pin 7 low
than threshold voltage --causing U901 to stop and restart periodically, check and repair
following circuits. Power transformer T901 bad; D903 short-circuit/opened.
3.2 No Display, power output normal.
3.2.1 Check and fix FBT B+：If no B+（27.5V）on pin2 of FBT replace D906, C916.
3.2.2 Check driving output voltage：0 or very low check and replace Q402, Q401.
3.2.3 Power off monitor. Check yoke connection. Use multimeter to check D501, D502, D401, Fix
if any is bad.
3.2.4 Power on, check voltage at pin10 of U401 if no voltage, check and fix Vertical circuit B+,
D904.
3.3 No Display (No Raster).
3.3.1 Check yoke connection.
3.3.2 Check CRT board and verify CRT heater is on.
3.3.3 Check G2 voltage if fail, check and fix FBT or D502.
3.3.4 Check K (cathode) voltage at negative of D501 about 150V, If no voltage output Check and
replace D501 and C501.
3.4 Vertical Deflection Failure
3.4.1 Vertical display can't be held--check and fix：U401.
3.4.2 Vertical raster abnormal (one horizontal line, size too small or fold back on top / bottom) -check and fix：14V supply at U402 pin2, if has voltage check and fix U301.
11
Appendix A. Spare Parts List
Location
F901
D901
D902
D501, D502
D903, D904, D301
D906, D401
Q901
Q201, Q202, Q206, Q402, Q501
Q205
Q502
Q203, Q204
U401
Parts Number
28-1100-0006
06-3100-0005
06-1100-0001
06-1100-0023
06-1100-0014
06-1100-0058
08-3100-0011
08-1100-0003
08-1100-0001
08-1100-0002
08-1100-0081
09-4100-0007
Description
Fuse, 2A/250V, slow blow
Diode 3A, 600V, RS407
Diode, 1.5A, 800V, BA159
Diode, 3A, 800V, FR107
Diode, FR1005
Diode, 2A, 600V, FR205
Power MOS 2SK2996
Transistor NPN 2SC1815
Transistor NPN 2SC2688
Transistor PNP 2SA1015
Transistor NPN 2SD667
IC TDA2579B
U301
U901
FBT
T401
T901
R902
R904
R614
09-4100-0119
09-4100-0087
11-0100-0054
41-2100-4009
11-2100-0095
01-3203-223J
01-01 2-*39J
01-2003-823J
IC TEA8172
IC UC3842
Flyback Transformer
Driver Transformer
Driver Transformer
CR 22K 3W
CF 0.39 1W
MOF 82K 3W
12
Appendix B. Schematics and PCB Layout Diagram
1. Schematics Page 1 -- Main Board, Video Board.
2. Schematics Page 2 – Power Supply, Video Amplifier
3. PCB Layout -- Video Board, Circuit Trace
4. PCB Layout -- Main Board, Silk Screen
13
A
B
C
1
PLUG AC SOCKET
W902
R911
3.9K
SYNC-
SYNC+
VR901
SVR 1KB
C912
104/50V
2
R901
560K
C902
0.1U/250V
C904
472/400V
Vfb
IC3842
R907
390
R909
27K
R908
47
D903
FR105
C914
EC 100U/25V
C906
47U/400V
D901
3A/600V
2
R906
1K
C909
1000P
D905 1N4148
R905
18
3
C910
562/100V
Ise
OUT
6
C903
472/400V
COMP
U901
C914
EC 100U/25V
EE-25
T902
R903
PEI 103 1M 1
R910
27K C911
C901
.1U/250V
2.5A/250V
F901
2
R904
.39
C908
472 /1KV
1
2
ERL-35
3
12
11
8
5
4
7
T901
6
POWER BOARD
G
Q901
2SK2996
D902
BA159
R902
R914
82K 3W 22K 3W
C907
.01 1KV
3
D907
FR105
C915
1000U/25V
D904
FR105
D906
HER205
OPTION
C918
EC 1000U/50V
12V
L901
56UH
13.5V
C916
EC 2200U/50V
R912
10 2W
27.5V
4
12.9V
4
R224
100
500
VR201
R221
1K
C217
47U/25V
Q205
2SC2688
C214
1U/25V
R225
4.7K
VR218
5K
R226
15K
R228
270
5
R413
22K
R227
270
VR603
2K
Date:
File:
B
Size
Title
VR203
3K
3
4
2
R6
4.7 1/4W
J501
CRT SOCKET
HEAT
HGND
K
330K
R515
VR501
2MB
6
Number
Sheet of
6
Revision
VM-901B/1201/1501B POWER/B CRT/B VR/B
680K
R225
C210
47U/200V
H-POSI
S201
SPARK GAP
OPTION
R223
1.5K 1/2W
R222
8.2K 2W
FUNCTION V-POSI
VR BOARD
W504(PIN5) W504(PIN2)
CONT
B+ 12.9V
GND VIN
1
2
3
W205
R224
150K
CRT BOARD
1
2
3
W204
5
5
G2
D
5
8
Vref
7
G4
1
7
VC
GND
Rt/Ct
4
D
S
6
G1
1
A
B
C
D
A
B
C
1
R312
33
C304
.047
R308
100
VR301
300B V-SIZE
R306
1.5 1W
R311
330K
VR401
H-HOLD
R304
1K
R302
2.2K
C303
.047
C309
4.7U
R315
470
2700P
1
1
7
R303
5.6K
D301
1N4002
C302
472
C411
103
18
R217 15K
R301
4.7K
2
U301
IC TDA8712
2
C409
17
2
R411
30K
16
3
U401
C304 2200P
TDA2579
C306
104
C308
1000U/25V
180 1/2W
R307
R408
12K
R406
18K
12.9V
C311
.022
C402
150P
R305
1
5
2.7 2W
R313
C305
100U/35V
C301
.15
R411
33K
C408
1U
R409
270
3
R410
2.2K
12.9V
R513
1.2K
1.2K
R510
12
C416
22U/50V
11
7
R413
5.6K
10
8
D
14
5
15
.15 C410
4
13
6
Q501
2SC945
C406
.1U
R511
1.8K
R512
1K
14V
C405
2.2U
R405
1.2K
R416
680
47
R418
VIDEO IN
1
2
R214
1.8K W201
C201
Q502
47U/16V
2SA733
C403
2.2U
R404
22
C402
150P
R401
820
4
R228
1K
R201
12K
C404
22U/25V
Q402
2SC1815
R403
5.6K
C407
100U/25V
R417
1K
4
R202 R203
15K 470
Q201
2SC1815
1
2
3
W503
Q401
IRF740
C202
220U/16V
C203
22U/25V
R219
330
Q204
2SC1815
C208
4.7U
C206
C560P 100V
R217
15K
5
R206
2.2K
R205
12K
D201
1N4148
R213
10K
R218
6.8K
5
R208
150
R207
120
Q202
2SC1815
R220
2.7K
R210
12K
Q206
2SC1815
R212
680
VR201
50K BRIGHT
C205
2.2U/50V
3
120 R209
2
6
4
3
8
Q203
2SC1815
3.3K R211
1
10U/16V C204
9
1.8 1W R306
8
7
6
5
4
3
2
1
W504
6
6
1
2
W701
D401
FR205
5
4
3
2
1
W702
C414
273/400V
R506
8.2 2W
B+ 27.5V
VR?
50KB
1
2
3
6
R702
8.2K
C702
562
C501
10U/250V
1
2
3
W502
4
3
2
1
5
6
7
8
C703
100U/16V
U701
LM386
C704
473
R703
10
C705
470U/25V
1
2
R704
33 2W
C706
1000U/16V
12V
8
J?
8/1W
Drawn By:
Date:
File:
7
Number
Size
8
Revision
VM-901B/1201/1501B W/AUDIO MAIN BOARD
C701
22U/25V
D501
FR107
D502
FR107
8
DY
W501
C502
223/630V
H.V
C501
10U/250V
L404
7
R701
10K
Title
FBT-3
C?
12UH
L402
1
2
3
4
7
A
B
C
D