Pioneer M-790 User manual

Service
ORDER NO.
RRV1465
STEREO POWER AMPLIFIER
M-790
THIS MANUAL IS APPLICABLE TO THE FOLLOWING MODEL(S) AND TYPE(S).
® This product is a system(s) component.
This
product
does
not
function
properly
when
independent;
to
avoid
malfunctions,
be
sure
to
connect
it
to
the
prescribed
system
component(s),
otherwise
damage
may
result.
CONTENTS
1. SAFETY INFORMATION uuu... ceeeeeseceescecseceessesesssece 2
2. PACKING, EXPLODED VIEWS AND PARTS LIST ...... 3
3. SCHEMATIC AND PCB CONNECTION DIAGRAMS ... 8
4. PCB PARTS LIST «..ccccceccssscscsstvessecscececscensesnccesesscasceescs 23
5. ADJUSTMENTS. .........c0c cece eecececesccececesececserevecseeeensucs 26
6. HOW TO CHECK M-790 1.0.0... ceececceceescsecseressueseseess 30
7. BLOCK DIAGRAN .............ccccccccceccscsssstesecesreseneeeeescess 31
8.
PANEL
FACILITIES
ooo...
cece
cccccscsescccesseueeeecseserees
32
9.
SPECIFICATIONS
0.00.0...
cele
cc
cc
eeeeccecestsscscsevereseseceseece
32
PIONEER
ELECTRONIC
CORPORATION
4-1,
Meguro
1-Chome,
Meguro-ku,
Tokyo
153,
Japan
PIONEER
ELECTRONICS
SERVICE,
INC.
P.0.Box
1760,
Long
Beach,
CA
90801-1760,
U.S.A.
PIONEER
ELECTRONIC
[EUROPE]
N.V.
Haven
1087,
Keetberglaan
1,
9120
Melsele,
Belgium
PIONEER
ELECTRONICS
ASIACENTRE
PTE.
LTD.
501
Orchard
Road,
#10-00
Lane
Crawford
Place,
Singapore
0923
©
PIONEER
ELECTRONIC
CORPORATION
1996
T-FFB
JAN. 1996
Printed
in
Japan

M-790
1. SAFETY INFORMATION
This service manual is intended for qualified service technicians; it is not meant for the casual
do-it-yourselfer. Qualified technicians have the necessary test equipment and tools, and have been
trained
to
properly
and
safely
repair
complex
products
such
as
those
covered
by
this
manual.
Improperly performed repairs can adversely affect the safety and reliability of the product and may void
the warranty. If you are not qualified to perform the repair of this product properly and safely, you should
not risk trying to do so and refer the repair to a qualified service technician.
WARNING
Lead in solder used in this product is listed by the California Health and Welfare agency as a known reproductive toxicant which
may cause birth defects or other reproductive harm (California Health & Safety Code, Section 25249.5).
When servicing or handling circuit boards and other components which contain lead in solder, avoid unprotected skin contact with
the solder. Also, when soldering do not inhale any smoke or fumes produced.
NOTICE
(FOR CANADIAN MODEL ONLY)
Fuse symbols -#&— (fast operating fuse) and/or -§&—® (slow operating fuse) on PCB indicate that replacement parts
must be of identical designation.
REMARQUE
(POUR MODELE CANADIEN SEULEMENT)
Les symboles de fusible -————H (fusible de type rapide) et/ou -§&—® (fusible de type lent) sur CCI indiquent que les
piéces de remplacement doivent avoir la méme désignation.
(FOR USA MODEL ONLY)
1.SAFETY PRECAUTIONS
The following check should be performed for the
ANY MEASUREMENTS NOT WITHIN THE LIMITS
OUTLINED ABOVE ARE INDICATIVE OF A PO-
continued protection of the customer and service
technician.
LEAKAGE CURRENT CHECK
Measure leakage current to a known earth ground
(water pipe, conduit, etc.) by connecting a leakage
current tester such as Simpson Model 229-2 or
metal parts of the appliance (input/output terminals,
screwheads, metal overlays, control shaft, etc.). Plug
the AC line cord of the appliance directly into a 120V
AC 60Hz outlet and turn the AC power switch on. Any
current measured must not exceed 0.5mA.
Leakage
current
tester
Reading should
not be above
0.5mA
Test all
exposed metal
surfaces
@) Also test with
plug reversed
(Using AC adapter
plug as required)
AC Leakage Test
equivalent between the earth ground and all exposed |
TENTIAL SHOCK HAZARD AND MUST BE COR-
RECTED BEFORE RETURNING THE APPLIANCE TO
THE CUSTOMER.
2.PRODUCT SAFETY NOTICE
Many electrical and mechanical parts in the appli-
ance have special safety related characteristics. These
are often not evident from visual inspection nor the
protection afforded by them necessarily can be ob-
tained by using replacement components rated for vol-
tage, wattage, etc. Replacement parts which have
these special safety characteristics are identified in
this Service Manual.
Electrical components having such features are
identified by marking with a A on the schematics and
on the parts fist in this Service Manual.
The use of a substitute replacement component which
dose not have the same safety characteristics as the
PIONEER recommended replacement one, shown in
the parts list in this Service Manual, may create shock,
fire, or other hazards.
Product Safety is continuously under review and
new instructions are issued from time to time. For
the latest information, always consult the current
PIONEER Service Manual. A subscription to, or ad-
ditional copies of, PIONEER Service Manual may be
obtained at a nominal charge from PIONEER.

2. PACKING, EXPLODED VIEWS AND PARTS LIST
NOTES:
e Parts marked by "NSP" are generally unavailable because they are not in our Master Spare Parts List.
e The L\ mark found on some component parts indicates the importance of the safety factor of the part. Therefore, when replacing, be sure to use
parts of identical designation.
e Parts marked by "@" are not always kept in stock. Their delivery time may be longer than usual or they may be unavailable.
2.1 PACKING
Parts List
Mark No. Description Parts No.
NSP 1 WARRANTY CARD (KUXJ TYPE ONLY) ARY1051
NSP 1 WARRANTY CARD (KCXJ TYPE ONLY) ARY1075
2 OPERATING INSTRUCTIONS RRB1167
(ENGLISH)
3. OPERATING INSTRUCTIONS RRC1005
(FRENCH)(KCXJ TYPE ONLY)
NSP 4 POLYETHYLENE BAG AHG1202
5 PACKING SHEET AHG7008
6 REAR PAD AHA1666
7 FRONT PAD AHA1665
8 PACKING CASE RHG1708

2.2 POWER AMP. UNIT SECTION
A
9
9
>
SS
SN
SA
9
Notes
NOTE : Screws adjacent to ¥ mark on @ Ensure that silicon grease does not adhere to the MOLD
product are used for disassembly. A (No. 6) and MOLD B (No. 7).
Parts List
Mark No. Description Parts No. Mark No. Description Parts No.
1 FRONTASSY RWZ3697 A 16 TRANSISTOR (Q13) 2SA 1837
2 REAR ASSY RWZ3698 A 17. TRANSISTOR (Q14) 2SA 1837
3. HEAT SINK ANH7008 A 18 TRANSISTOR (Q53) 2SA 1837
4 BRACKET RNE1881 A 19 TRANSISTOR (Q54) 2SA 1837
5 MICA SHEET REE1029 A 20 TRANSISTOR (Q17) 2SC3181N
6 MOLDA AMR7005 A 21 TRANSISTOR (Q18) 2SC3181N
7 MOLDB AMR7006 A 22 TRANSISTOR (Q57) 2SC3181N
8 SCREW (3x10) ABAI021 A 23. TRANSISTOR (Q58) 2SC3181N
9 SCREW BBZ30P140FZK A 24 TRANSISTOR (Q11) 2SC4793
10 SCREW BPZ30P350FZK A 25 TRANSISTOR (Q12) 28C4793
11 DCFAN MOTOR AXM7003 A 26 TRANSISTOR (Q351) 28C4793
A 12. TRANSISTOR (Q15) 2SA1264N A 27 TRANSISTOR (Q52) 28C4793
A 13. TRANSISTOR (Q16) 28A1264N
A 14. TRANSISTOR (Q55) 2SA1264N
A 15 TRANSISTOR (Q56) 2SA1264N
4

5
2
4
M-790
2.3 EXTERIOR
29
See
ey
31
(KUXJ type only)
12
Refer to "2.2 POWER AMP. UNIT SECTION"

Parts List
Mark No. Description Parts No.
NSP 1 CHASSIS RNE1874
2 INSULATOR ASSY PNW1912
3 INSULATOR ASSY DXA1490
NSP 4 PCB HOLDER AEC1583
5 REAR PANEL RNA2037
6 PCB MOLD AMR2533
7 AFASSY RWZ3686
8 PCB SUPPORT AEC1581
A 9 FUSE (FUISI, 8.0A): REK1086
10 SECONDARY ASSY RWZ3692
11 PRIMARY ASSY RWZ3772
12 POWER AMP. UNIT RXQ7024
13. PUSH RIVET AEC7010
A 14 AC POWER CORD PDG1015
15 CORD STOPPER AEP - 113
16 SPASSY RWZ3690
A 17. POWER TRANSFORMER (T1) RTT1307
18 REGURATOR ASSY RWZ3687
19 FRONT PANEL RAH2692
20 POWER SW ASSY RWZ3691
21 POWER BUTTON AAD7064
22 INDI. LENS AAK7075
23 LED ASSY RWZ3689
24 H.PASSY RWZ3688
25 SPEAKER BUTTON AAD2416
26 ILLUMI. PANEL RAH2696
27. NAMEPLATE PAM1608
28 BONNET CASE ANE1528
29. SPACER REB1300
90° Sei vaciessy
31 65LABEL(KUXJTYPEONLY) ORW1069
32 SCREW (3X18) ABA1018
33. SCREW (2.6%8) ABA1095
34. SCREW BBZ30P080FZK
35. SCREW BBZ40P080FZK
36 SCREW BPZ26PO80FMC
37 SCREW VPZ30PO80FZK
38 BINDER AEC - 826
39 BINDER AEP — 215
40 SCREW BBT30P080FZK
M-790

M-790
3. SCHEMATIC AND PCB CONNTCTION DIAGRAMS
NOTE FOR SCHEMATIC DIAGRAMS (Type 1A)
1. When ordering service parts, be sure to refer to
"PARTS LIST of EXPLODED VIEWS" or "PCB
PARTS LIST".
2. Since these are basic circuits, some parts of them or the
values of some components may be changed for improve
ment.
3. RESISTORS:
Unit: k:kQ, M:MQ, or Q unless otherwise noted.
Rated power: 1/4W, 1/6W, 1/8W, 1/10W unless otherwise
noted.
Tolerance: (F): 1%, (G): 2%, (K): £10%, (M): +20% or +5% un-
less otherwise noted.
4. CAPACITORS:
Unit: p:pF or uF unless otherwise noted.
Ratings: capacitor (uF)/voltage(V) unless othrewise noted.
Rated voltage: 50V except for electrolytic capacitors.
5. COILS:
Unit: m:mH or pH unless otherwise noted.
6. VOLTAGE AND CURRENT:
: Signal voltage at rated output.
LJ ore V:
DC voltage (V) at no input signal unless otherwise noted.
Value in ( ) is DC voltage at rated power.
o mA or — mA:
DC current at no input signal unless otherwise noted.
7. OTHERS:
*@ or@ : Adjusting point.
° ~@ : Measurement point.
* The A\ mark found on some component parts indicates the im-
portance of the safety factor of the parts. Therefore, when re-
placing, be sure to use parts of identical designation.
8. SCH-C ON THE SCHEMATIC DIAGRAM:
¢ SCH-C indicates the drawing number of the schematic dia
gram. (SCH stands for schematic diagram.)
9. SWITCHES (Underline indicates switch position):
H.P ASSY
$201 : SPEAKERS(A / A+B)

—I
3.1 OVERALL WIRING DIAGRAMS
=
> fave
=
east
fe
(RWZ 3688)
(~SCH-2)
REAR L
REAR L
REAR R
REAR R
CENTER t |
CENTER ee
SP ASSY
(RWZ 3690)
(>SCH-2)
OVERALL WIRING DIAGRAMS
SCH-1
SP-L-A OUT
SP-L-A OUT
GND
SP-R-A+B OUT
SP—-R-A+B OUT
9} SP—R-A OUT
SP-R-A OUT
CN210
GND
CN110
TO TUNER CONTROL AMP.
FRONT ASSY
POWER
AMP.UNIT
(RXQ7024)
(=SCH
(RW23697)
—3)
(}/POWER RY (9)/PRO GND O)IM.+12V @)REAR OUT ©)/s GND (S)| CENTER OUT
-~12V
@IR out @IF GND Mit out
©) +12Vv
J7601
(Cx—790, CX-770S)
POWER SW
ASS
(RWZ 3691)
(+SCH-2)
P155
CHASSIS
AF ASSY
(RWZ 3686)
(~SCH—2)
CN109
OOO @QVODNDOoWOWO
CHASSIS
(RWZ 3687)
(-=SCH-2)
(RWZ 3698)
(>~SCH-4)
NEUTRAL
. AC POWER CORD
PDG1 01S
AC120V 60Hz
POWER TRANSFORMER
A
RTT1307
CN153
REGURATOR ASSY
OVERALL WIRING DIAGRAMS
SCH-1
M-790
10

4
M-790
3.2 AF, REGURATOR, H.P., LED, SP, POWER SW, SECONDARY AND PRIMARY ASSEMBLIES |
SIGNAL ROUTE
= -AUDIO SIGNAL (FRONT)
[POWER SW
| ASSY
| (RWZ3691)
P156
— eB oscacas, |
accios4
swiS4
Aaso-sss |p455 H
RDX1014
————
SS
tetra
i
i63.
YT
Qo
ay
ee
ea
eae
al
aia
NOTE
Pr}
3P
on
RESISTORS
5a
ACS
OUTPEL
Indicated
in
TS
45
A
Fuis)
AAIS3
TO
Uniess
otherwise
novedt5%
CAUT1ON:
FOR
CONTINUED
PROTECTION
aie
aa
t
sare)
LIVE
AC
POWER
® Flameproof type (RD1/4PMF)
@ Flameproof Quick Open Type (RFA1/4PS)
CAPACITORS
Indicated in capacity (uF) /vol tage (V)
M CQMA (film type)
DIODES
Unless otherwise specifid
AGAINST RISK OF FIRE,
REPLACE ONLY WITH SAME
TYPE ANO RATINGS ONLY.
|
1086
nee A A1S2
AKFI1E
KN104
NF 1084
CSA AC125)
ORD Cc
NEUTRAL] (4scH-1)
ADK7039
2
[> :AUDIO SIGNAL (REAR) diodes shall be HSS104-02 RY151 RELAY for AC OUTPUT ; i aA,
CONTROL We oO CAUTION: FOR CONTINUED PROTECTION
B49 2 Ma zaw AGAINST RISK OF FIRE,
AF ASSY (RWZ 3686) Oo KN1S1 REPLACE WITH SAME TYPE
Ne ges NO. 1CP-NSO, MFD BY ROHM
CoO., LTD.FOR 1€151-1C154.
eee) CER 8 a ee
| |
SP-L-A+B OUT PETA ET] eee | a eK ww AC +10V (OC) | ASSY
SP-L-A+B OUT Mca 4h 4 ovo7$ | (RWZ 3692)
SP-L_ IN 174 A106 cuz ]
SP-L IN 188 10480 0106 §
SP-L-A OUT var seivioc] |
OUT ACH124 9. OsSB20F
Aco | |
stain. L
) : GND
a {
a GND \
) GND an
d ©} 7.5 [| Be i] |
>
piozA
|
®
D3SBA20
(8)
_
a
-B1
aX
|
, -B1 IZn |
3
er
a,
lew
|
75A11-300-2651 ike |
0)
arma || | | | |
®
R206 270
| ah I ‘ o1o3 A ER TRANSFORMER
!
ii0
02SBA20
(8)
7!
RITI307
4 : Si i—
aii a a A a
SP-R-A OUT |®
SP-R-A
GND
|©
mer
ists
=85
-22v
(0c)
SP-R-B
GND
|©
CONTROL
A
|
SP-R-B OUT |@ 16101 |
a 49 R129 NyM7 0M 6FA [+5 ev] |
SP-L-A
OUT
1@
POWER-OFF
_0.5V
aw
c2
|
(9423S
=—
5
-S=
7
-L-A cia CN103
aes
See
:
2541046
1750
Pca
009
anT)
009
po-------- -- == = a © GND
| @f210 eae ¢205 SP-L-B OUT © UNREG-—
ao | (aaee HEE) | ates !
I
I
asansis
@}
M.t+12Vv
{
5P202
AKE10121 P © Rie
REARAL OUT, I cni02 | = DIESE REO-zEST | {
REAR/L GND Meri 022 AKT1022 | |
REARZR GNDIO REAR GNO © RI0 | I !
mean /n OUrlp near oxo for | ape Toh eae ou |
REAR OUT OS TAIZ A112 pss | Saas
REAR
ouT
|
tH
|
SUPPLY
CONTROL
| I
7
CENTER SP OUT CENTER GND Cm (ar) al etal |
ea conta CENTER GND |@ ed aioe 33K |
sp203 | CENTER OUT O77 | l |
AKE1032 | ere dh CENTER OUT |@ R109 6BK | I I
i]
iwaw
J102
|
25c2458
+-——
[|
,
|
|
valstora
|
I
|
DTSA08=150-2657
|
LH
|
|
(C303
&
|
! t N f : ! | |
j SP ASSY (RWZ3690) | | REGURATOR ASSY
b—-————-—-———---— = L__—------~— 88668000 00000006000O----- 0090000 0000){0000506660+----4060606000|--------------- | | (RWZ3687) \
CN104 > kK, _AKP7001 CNTO KP250NA10 CN106 KP2S0NA9 CN107 KPES Q106, Q109'M.+12V POWER Me eres ta es ee |
Ne N>OZOTOS>2X2AF>EDA ia) Zz SUPPLY CONTROL
SOON Oe =o ZAN08 8A585 oe ea oa) SOZINSE OE APRLSERE
<fC€¢ -G6 -GLO-- Gz-d60 676 Lrao°e 6° a 560 -aetG6i-4
: mM oe tte wl oe we -stit+ VU nut! +31 n+e
uwtitju+Orr se: cog mut emery, ast wn > vlan ;
>uL>
rT
O¢g2
YG
w
fe
Ww
2
,
TO TUNER CONTROL AMP TO FRONT ASSY TO REAR ASSY TO REAR ASSY
(CX-790, CX-770S) CN7502 (@SCH-3) CN7102 (> SCH—-4) J7101 (@®SCH-4)
AF ASSY, REGURATOR ASSY, H.P.ASSY,
LED ASSY, SP ASSY, POWER SW ASSY,
SECONDARY ASSY, PRIMARY ASSY
AF ASSY, REGURATOR ASSY, H.P.ASSY,
LED ASSY, SP ASSY, POWER SW ASSY,
SECONDARY ASSY, PRIMARY ASSY
SCH-2 SCH-2
11
N
=

_]
SP ASSY
Reie
cees
Otho
TO AF ASSY CN102
TO AF ASSY CN101
H.P. ASSY
SPR IN | NE M PFe
889SZMuY
ASSU “d°H
LED ASSY
LED ASSY RWZ3689
fPono Pperonty }
se@e0
NE M PF2
M-790
NOTE FOR PCB DIAGRAMS:
1. ee ee ee ae nee es
2. A omsenséd bedlioana ah pan nOBend schematic
diagrams is shown below.
Symbol in Schematic
Diagrams
BceEBCE
Transistor
Transistor
with resistor
Field effect
transistor
Resistor array
3-terminal
regulator
TO
AF
ASSY
CN110
RNP
1644-B
e This diagram is viewed from the mounted parts side.
e The parts mounted on this PCB include all necessary parts for several destinations.
For further information for respective destinations, be sure to check with the schematic diagram.
at ; 2
13
| 3