Only qualified service technicians who are familiar with safety checks
and guidelines should perform service work. Before replacing parts,
disconnect power source to protect electrostatically sensitive parts. Do
not attempt to modify any circuit unless so recommended by the
manufacturer. When servicing the receiver, use an isolation transformer
between the line cord and power receptacle.
SERSER
SER
SERSER
Use EXTREME CAUTION when servicing the high voltage circuits. To
discharge static high voltage, connect a 10K ohms resistor in series with a
test lead between the receiver ground and CRT anode lead. DO NOT lift
the CRT by the neck. Always wear shatterproof goggles when handling
the CRT to protect eyes in case of implosion.
X-RAX-RA
X-RA
X-RAX-RA
Be aware of the instructions and procedures covering X-ray radiation. In
solid-state receivers and monitors, the CRT is the only potential source of
X-rays. Keep an accurate high voltage meter available at all times. Check
meter calibration periodically. Whenever servicing a receiver, check the
high voltage at various brightness levels to be sure it is regulating
properly. Keep high voltage at rated value, NO HIGHER. Excessive high
voltage may cause X-ray radiation or failure of associated components.
DO NOT depend on protection circuits to keep voltage at rated value.
When troubleshooting a receiver with excessive high voltage, avoid close
contact with the CRT. DO NOT operate the receiver longer than
necessary. To locate the cause of excessive high voltage, use a variable
AC transformer to regulate voltage. In present receivers, many electrical
and mechanical components have safety related characteristics which are
not detectable by visual inspection. Such components are identified by a
# on both the schematic and the parts list. For SAFETY, use only
equivalent replacement parts when replacing these components.
GENERAL GUIDELINESGENERAL GUIDELINES
GENERAL GUIDELINES
GENERAL GUIDELINESGENERAL GUIDELINES
Perform a final SAFETY CHECK before returning receiver to customer.
Check repaired area for poorly soldered connections, and check entire
circuit board for solder splashes. Check board wiring for pinched wires or
wires contacting any high wattage resistors. Check that all control knobs,
shields, covers, grounds, and mounting hardware have been replaced. Be
sure to replace all insulators and restore proper lead dress.
WARNINGWARNING
VICE
WARNING
VICE VICE
WARNINGWARNING
VICING VICING
VICING
VICING VICING
Y RADIAY RADIA
Y RADIA
Y RADIAY RADIA
THE HIGH THE HIGH
THE HIGH
THE HIGH THE HIGH
TION AND HIGH TION AND HIGH
TION AND HIGH
TION AND HIGH TION AND HIGH
VV
OLOL
V
OL
VV
OLOL
TT
AA
GE AND CRGE AND CR
T
A
GE AND CR
TT
AA
GE AND CRGE AND CR
VV
OLOL
TT
V
OL
T
VV
OLOL
TT
TT
T
TT
AA
GE LIMITSGE LIMITS
A
GE LIMITS
AA
GE LIMITSGE LIMITS
UTIONSUTIONS
UTIONS
UTIONSUTIONS
SAFETY CHECKS — FIRE AND SHOCK HAZARDSAFETY CHECKS — FIRE AND SHOCK HAZARD
SAFETY CHECKS — FIRE AND SHOCK HAZARD
SAFETY CHECKS — FIRE AND SHOCK HAZARDSAFETY CHECKS — FIRE AND SHOCK HAZARD
Cold LeakaCold Leaka
Cold Leaka
Cold LeakaCold Leaka
Unplug the AC cord, connect a jumper across the plug prongs, and turn
the power switch on (if applicable). Use an ohmmeter to measure the
resistance between the jumped AC plug and any exposed metal cabinet
parts such as antenna screw heads, control shafts, or handle brackets.
Exposed metal parts with a return path should measure between 1M
ohms and 5.2M ohms. Parts without a return path must measure infinity.
Hot LeakaHot Leaka
Hot Leaka
Hot LeakaHot Leaka
Plug the AC cord directly into an AC outlet. DO NOT use an isolation
transformer. Use a 1500 ohms, 10W resistor in parallel with a .15µF
capacitor to connect between any exposed metal parts on the receiver and
a good earth ground. (See figure below.) Use an AC voltmeter with at
least 5000 ohms per volt sensitivity to measure the voltage across the
resistor. Check all exposed metal parts and measure voltage at each point.
Voltage measurements should not exceed .75VAC, 500µA. Any value
exceeding this limit constitutes a potential shock hazard and must be
corrected. If the AC plug is not polarized, reverse the AC plug and repeat
exposed metal part voltage measurement at each point.
gg
e Chece Chec
e Chec
e Chece Chec
ks fks f
ks f
ks fks f
g
gg
gg
e Current Chece Current Chec
g
e Current Chec
gg
e Current Chece Current Chec
or Receiveror Receiver
or Receiver
or Receiveror Receiver
kk
k
kk
s with Isolated Grs with Isolated Gr
s with Isolated Gr
s with Isolated Grs with Isolated Gr
oundound
ound
oundound
SET 4703SET 4703
SET 4703SET 4703
SET 4703
MODEL B27B40ZMODEL B27B40Z
MODEL B27B40ZMODEL B27B40Z
MODEL B27B40Z
High Voltage Shutdown Test .................. 1
IC Functions ........................................... 4
Important Parts Information ................... 3
Miscellaneous Adjustments .................... 1
Parts List ................................................. 4
PIP IF .............................................. 3
Power Supply .................................. 2
System Control ................................ 3
Television ........................................ 2
Service Mode Adjustment Chart ............ 1
Test Equipment....................................... 3
Tuner Information .................................. 1
INDEXINDEX
INDEX
INDEXINDEX
Technical Service Data
ZENITHZENITH
ZENITH
ZENITHZENITH
Model B27B40ZModel B27B40Z
Model B27B40Z
Model B27B40ZModel B27B40Z
Representative Model
ff
or seror ser
f
or ser
ff
or seror ser
Essential coEssential co
Essential co
Essential coEssential co
vicing a televicing a tele
vicing a tele
vicing a televicing a tele
ScSc
hematicshematics
•
Sc
hematics
ScSc
hematicshematics
veravera
gg
vera
veravera
vision receivervision receiver
vision receiver
vision receivervision receiver
ee
g
e
gg
ee
......
...
......
4703
HIGH HIGH
VV
OLOL
TT
AA
HIGH
V
HIGH HIGH
VV
Turn receiver on, adjust customer controls for normal operation. Temporarily apply an external bias of
14.0V to the emitter of QX3002. The receiver should lose raster. If the receiver does not lose raster the
shutdown circuit should be repaired. Remove AC power, wait 30 seconds and test for normal operation.
The listing of any available replacement part herein in no case constitutes a recommendation, warranty, or guarantee by
SAMS Technical Publishing as to the quality and suitability of such replacement part. The numbers of the listed parts have
been compiled from information furnished to SAMS Technical Publishing by the manufacturers of the specific type of
replacement part listed.
Reproduction or use, without express permission, of editorial or pictorial content, in any manner, is prohibited. No patent
liability is assumed with respect to the use of the information contained herein.
VHF High Band voltages taken on channel 7.
UHF Band voltages taken on channel 14
SUB SUB
SUB
SUB SUB
w Bandw Band
w Band
w Bandw Band
TUNER TUNER
TUNER
TUNER TUNER
VV
OLOL
TT
AA
V
VV
VV
V
VV
GE CHARGE CHAR
OL
T
A
GE CHAR
OLOL
TT
AA
GE CHARGE CHAR
VHF High BandVHF High Band
VHF High Band
VHF High BandVHF High Band
OLOL
TT
AA
GE CHARGE CHAR
OL
T
A
GE CHAR
OLOL
TT
AA
GE CHARGE CHAR
TT
T
TT
TT
T
TT
UHF BandUHF Band
UHF Band
UHF BandUHF Band
MAIN MAIN
MAIN
MAIN MAIN
SUB SUB
SUB
SUB SUB
TUNER TUNER
TUNER
TUNER TUNER
(2)
(4)
(6)
(8)
(10)
TUNER TUNER
TUNER
TUNER TUNER
TERMINAL GUIDETERMINAL GUIDE
TERMINAL GUIDE
TERMINAL GUIDETERMINAL GUIDE
(1)
τ
τ
(3)
τ
τ
(5)
τ
τ
(7)
τ
τ
(9)
τ
τ
(11)
τ
TERMINAL GUIDETERMINAL GUIDE
TERMINAL GUIDE
TERMINAL GUIDETERMINAL GUIDE
MISCELLANEOUS ADJUSTMENTS
This receiver employs digital customer controls which are accessed through
the service menu. All adjustments were performed at reset unless otherwise
indicated. Record all the data values for all functions in the service menu
before making any changes.
HIGH HIGH
VV
OLOL
TT
AA
V
OL
VV
OLOL
GE CHECKGE CHECK
T
A
GE CHECK
TT
AA
GE CHECKGE CHECK
HIGH
HIGH HIGH
Tune in a picture. Set brightness and color to minimum. Connect a high
voltage probe to CRT anode. High voltage should read from 27kV to 29kV.
SERSER
VICE MENUVICE MENU
SER
VICE MENU
SERSER
VICE MENUVICE MENU
To access the service menu adjustments by using the remote transmitter
keypad, press and hold the menu button until the menu display disappears
from the screen. Key in 9, 8, 7, 6, and press the enter button.
To access the service menu adjustments by using the receiver keypad, press
the menu button until the display disappears from the screen. Without
releasing the menu button simultaneously press the adjust right and channel
up buttons.
The receiver is now in service menu mode with function 03 H Pos 16
displayed. The first line on the service menu is a version number of the
software used in the receiver. On the bottom is a date the module went
through the factory. Use the select up and down buttons to select function.
Use the adjust buttons to make changes to selected function. The function
00 F Mode (Factory Mode) is always set to 0. Only the first seven items in
the service menu can be brought up. Use the select key to select the 00 F
Mode function and change the adjustment to 1, now all the menu items will
be accessible.
NOTE: Set value of function 00 F Mode (Factory Mode) to 0 before exiting
the service menu mode. If not set to 0 the receiver will not shut off with the
remote or power button on the receiver.
HORIZONTHORIZONT
HORIZONT
HORIZONTHORIZONT
Tune in a crosshatch pattern. Call up service menu, select function 11, set
data value for slight overscan on both sides.
RF ARF A
RF A
RF ARF A
Tune in a picture. Adjust R1202 to a point where snow appears in picture,
then to a point where snow disappears.
COLOR COLOR
COLOR
COLOR COLOR
Tune in a crosshatch pattern. Set brightness, picture, and color to minimum.
Call up service menu, select functions 27, 28, and 29, set data values to 0.
Adjust data values for functions 30, 31, and 32 of the two least predominate
colors to obtain a white pattern. Tune in an active black and white channel
and adjust functions 27, 28, and 29 for best white to black tracking at high
and low brightness.
COLOR PURITY / CONVERGENCECOLOR PURITY / CONVERGENCE
COLOR PURITY / CONVERGENCE
COLOR PURITY / CONVERGENCECOLOR PURITY / CONVERGENCE
CRT and yoke are bonded. Color purity and convergence adjustments are
not recommended.
VHF High Band voltages taken on channel 7.
UHF Band voltages taken on channel 14
VHF LoVHF Lo
VHF Lo
VHF LoVHF Lo
w Bandw Band
w Band
w Bandw Band
VHF High BandVHF High Band
VHF High Band
VHF High BandVHF High Band
UHF BandUHF Band
UHF Band
UHF BandUHF Band
(2)
(4)
(6)
(8)
(10)
(1)
τ
τ
(3)
τ
τ
(5)
τ
τ
(7)
τ
τ
(9)
τ
τ
(11)
τ
SERVICE MODE ADJUSTMENT CHART
SET 4703 PSET 4703 P
SET 4703 P
SET 4703 PSET 4703 P
aa
gg
e 1e 1
a
g
e 1
aa
gg
e 1e 1
FUNCTIONFUNCTION
FUNCTION
FUNCTIONFUNCTION
221-01389221-01389
221-01389
221-01389221-01389
00 F Mode000 - 1Factory Mode. Normal setting is 0, when set to 1, all other functions are accessible.
01 Pre Px010 - 1Stores customer video menu picture preference (P RESET). 0 is custom,
02 V Pos15160 - 30Vertical position of On Screen Displays (Menus & Captions).
03 H Pos42420 - 80Horizontal position of On Screen Displays (Menus & Captions).
04 Level110 - 205 Band000 - 7This setting depends upon input signal. 0 Broadcast Fixed, 1 CATV AFC,
06 AC On000 - 1Enables AC Power On feature.
07 RF Brt15140 - 31RF Brightness.
08 Ax Brt15140 - 31Auxiliary Brightness.
09 Max Con63350 - 63Maximum Contrast.
10 V Size38240 - 63Vertical Size.
11 H Size63310 - 63Horizontal Size.
12 V Phase42460 - 63Vertical Phase.
13 H Phase0130 - 63Horizontal Phase.
14 H Osc790 - 31Horizontal Osc.
15 S Corr770 - 31S Correction.
16 V Linea770 - 15Vertical Linearity.
17 Pin Amp63230 - 63Pin Amp.
18 C Pin63300 - 63Corner Pin.
19 Trapez1570 - 15Trapezium.
20 EHT Com7150 - 15 EHT Comp.
21 AFC Bow770 - 15AFC Bow.
22 AFC Ang770 - 15AFC Angle.
23 Up V Lin660 - 15Upper Vertical Linearity.
24 Lo V Lin000 - 15Lower Vertical Linearity.
25 AFC G100 - 3AFC Gain.
26 EWDC100 - 1EWDC.
27 R Cut080 - 15Red Cutoff.
28 G Cut010 - 15Green Cutoff.
29 B Cut000 - 15Blue Cutoff.
30 R Gain31480 - 63Red Gain.
31 G Gain31350 - 63Green Gain.
32 B Gain31300 - 63Blue Gain.
33 Dynam C000 - 1Dynamic C Video.
34 Gamma000 - 3Gamma Register.
35 DCTran110 - 1DCTran Video.
36 C Bpf100 - 1C Bpf Video.
37 C Trap110 - 1C Trap Off Video.
38 FSC Sw000 - 1FSC Sw Video.
39 ABL Mode110 - 1ABL Mode Video.
40 ABLVTH110 - 1ABLVTH Video.
41 6 Keys110 - 1Set to 0 for the 10 key keyboard, set to 1 for the 6 key keyboard.
42 A Att970 - 15Audio Input Attenuator.
43 A VCO31310 - 63Audio Voltage Controlled Oscillator.
44 A Filter31270 - 63Audio Filter.
45 ASpectral31120 - 63High Frequency Separation.
46 W Band31310 - 63Low Frequency Separation.
47 PIP X117200 - 254Horizontal position on left side.
48 PIP Y125230 - 254Vertical position on left side.
49 PIP X21131170 - 254Horizontal position on right side.
50 PIP Y21431510 - 254Vertical position on right side.
51 PIP Adj230 - 15Picture In Picture Adjustment.
52 PIP Y DL410 - 15Picture In Picture Y Delay.
53 PIP Y Off31310 - 31Picture In Picture Y Offset.
54 PIP ACC20200 - 63Picture In Picture ACC Level.
55 P BGST10100 - 63Picture In Picture BG Stat Level.
56 PIP HX22250 - 63Picture In Picture HX.
57 PIP VXS37380 - 63Picture In Picture VXS.
58 PIP R Con50140 - 63Picture In Picture Red Contrast.
59 PIP G Con50150 - 63Picture In Picture Green Contrast.
60 PIP B Con50170 - 63Picture In Picture Blue Contrast.
61 PIP Comp220 - 3Picture In Picture Comp.
62 YUV Brt1000 - 31YUV Sub-Brightness.
63 Min Con10250 - 31Minimum Contrast Value.
64 F Jacks110 - 1Front Jacks.
65 PIP Brt2002010 - 254Picture In Picture Brightness.
66 Xtal000 - 1Select Crystal or RC circuit Oscillator for OSD.
67 Min Brt25250 - 63Custom Minimum Brightness.
68 Max Brt35350 - 63Custom Maximum Brightness.
69 GM PIP X15150 - 50PIP X position for gemstar.
70 GM PIP Y17170 - 30PIP Y position for gemstar.
71 GM Pos X36360 - 60OSD X position for gemstar.
72 GM Pos Y13130 - 36OSD Y position for gemstar.
73 GM Siz X1101100 - 152OSD X Size for gemstar.
74 GM Siz Y1001000 - 233OSD Y Size for gemstar.
75 Mut Brt20200 - 63Level Brightness when mute.
76 Mut Con20200 - 63Level Contrast when mute.
77 GMVSize30300 - 63GMVSize.
DD
AA
TT
D
A
T
DD
AA
TT
VV
ALUEALUE
V
ALUE
VV
ALUEALUE
AA
A
AA
ON-SETON-SET
ON-SET
ON-SETON-SET
VV
ALUEALUE
V
ALUE
VV
ALUEALUE
VV
ALUEALUE
V
ALUE
VV
ALUEALUE
RANGERANGE
RANGE
RANGERANGE
NONO
NO
NONO
TESTES
TES
TESTES
ZENITH MODEL B27B40Z
ZENITH MODEL B27B40ZZENITH MODEL B27B40Z
ZENITH MODEL B27B40ZZENITH MODEL B27B40Z
SET 4703 PSET 4703 P
SET 4703 P
SET 4703 PSET 4703 P
aa
gg
e 1e 1
a
g
e 1
aa
gg
e 1e 1
PP
aa
gg
e 2e 2
g
gg
e 2
e 2e 2
SET 4703 SET 4703
SET 4703
SET 4703 SET 4703
P
a
PP
aa
SET 4703 PSET 4703 P
SET 4703 P
SET 4703 PSET 4703 P
aa
gg
e 2e 2
a
g
e 2
aa
gg
e 2e 2
PP
aa
gg
e 2e 2
a
g
e 2
aa
gg
e 2e 2
SET 4703 SET 4703
SET 4703
SET 4703 SET 4703
P
PP
ZENITH MODEL B27B40Z
ZENITH MODEL B27B40ZZENITH MODEL B27B40Z
ZENITH MODEL B27B40ZZENITH MODEL B27B40Z
SET 4703 PSET 4703 P
SET 4703 P
SET 4703 PSET 4703 P
aa
gg
e 2e 2
a
g
e 2
aa
gg
e 2e 2
PP
aa
gg
e 3e 3
a
g
e 3
aa
gg
e 3e 3
SET 4703 SET 4703
SET 4703
SET 4703 SET 4703
P
PP
SET 4703 PSET 4703 P
SET 4703 P
SET 4703 PSET 4703 P
ImporImpor
tant Ptant P
arar
ts Infts Inf
Impor
tant P
ImporImpor
ν The parts listed here are those not usually available from a well-stocked supply cabinet or bin.
ν Where items may be replaced with equivalent parts, several alternates are shown from participating vendors.
ν On the parts lists, safety items are marked with a
these items.
ν When ordering parts, state the model number, part number, and description.
ar
tant Ptant P
arar
# #
# to remind you that only exact replacements are recommended for
# #
ts Inf
ts Infts Inf
ormationormation
ormation
ormationormation
aa
gg
e 3e 3
a
g
e 3
aa
gg
e 3e 3
Obtaining PObtaining P
Obtaining P
Obtaining PObtaining P
Many of these parts are available from your local Sams authorized distributor or the manufacturer of the equipment. Call
Sams for the name of your nearest distributor:
arar
ar
arar
tsts
ts
tsts
800-428-7267
Or consult the Sams
Information on test equipment and replacement parts is listed in these pages for the following participating vendors.
Consult the Sams
ν NTE Electronics, Inc. (NTE)
Test equipment listed by participating manufacturer illustrates typical or equivalent equipment used by Sams engineers to obtain
measurements. This equipment is compatible with most types used by field service technicians.
EquipmentEquipment
Equipment
EquipmentEquipment
OscilloscopeSC3100
Generators
RGBCM2125
Multiburst SignalVG91
Color BarVG91
TV StereoVG91
Digital VOMSC3100
Frequency MeterSC3100
Hi-Voltage ProbeHP200
Accessory ProbesTP212
Annual Index
Annual Index
for the address of the original equipment manufacturer.
PP
arar
ticipating ticipating
P
ar
ticipating
PP
arar
ticipating ticipating
for their current address.
TEST EQTEST EQ
TEST EQ
TEST EQTEST EQ
Sencore No.Sencore No.
Sencore No.
Sencore No.Sencore No.
VV
endorendor
endor
endorendor
ss
s
ss
V
VV
ν Sencore, Inc.
UIPMENTUIPMENT
UIPMENT
UIPMENTUIPMENT
EquipmentEquipment
Equipment
EquipmentEquipment
Isolation TransformerPR570
Capacitance AnalyzerLC102
CRT AnalyzerCR7000
AC Leakage TesterPR570
Inductance AnalyzerLC102
Flyback Yoke TesterTVA92
Field Strength MeterSL753
Transistor TesterTF46
Horizontal AnalyzerHA-2500
Video AnalyzerVG91, TVA92
SP1, 2Speaker049-01368-036cm X 13cm, 8 Ohms, 5W
SW1Switch-On/Off
SW2Switch-Channel Up
SW3Switch-Channel Down
SW4Switch-Volume Up
SW5Switch-Volume Down
SW6Switch-Menu