Instruction manual

GUARANTEE
We guarantee the performance of this equipment and the mechanical and electrical workmanship to be
free of serious defects for a period of
90 days. This guarantee does not extend to components damaged by im-
proper use
nor does it extend to transportation to and from the factory.
SERVICE INFORMATION
All Mcintosh equipment IS designed for long trouble free operation. All components are of highest
quality
and are conservatively operated. If trouble develops the amplifier may be serviced by your franchised
dealer, a competent serviceman,
or returned to the factory. Equipment will not be accepted at the factory
unless factory
return authorization is first received. The following chart of operating voltages and resistances
is offered as a guide for servicing the unit. All voltages
and resistences are measured to chassis except
those
with asterik (*). These are measured to chassis with pin #2 of either 5U4GA grounded. Voltages are
measured with high impedence VTVM. NOTE-UNIT MUST BE TURNED OFF WHEN MEASURING
RESISTENCES.
Tube
12AX7
(input)
12AU7
12BH7
Pin No.
1
2
3
4&5
6,7 & 8
9
1
2
3 & 8
4&5
6
7
9
1
2
3 & 8
4 & 5
6
7
9
VOLTAGE AND RESISTANCE CHART
DC Volts
No Signal
120
-e-
1.1
Filament
Filament
240
120
129
Filament
240
96
Filament
352
--e--
18
Filament
352
--a-
Filament
DC Volts
30W out
102
--e--
1
(6.3V
AC to pin 9)
210
102
108
(6.3V
AC to pin 9)
210
86
295
-e--
15.5
(6.3V
AC to pin 9)
295
--a-
--4-
AC Volts
30Wout
1.5
.42
.4
10
1.5
.5
132
10
.4
132
10
Resistance
Unit Off
380K*
27K (gain
C.C.W.)
3.3K
-B-(hum
C.C.W.)
40K*
380K*
18K
40K*
2.5K*
12.2K*
220K
1.2K
12.2K*
220K