McIntosh MC-75 Service manual
McIntosh Laboratory, Inc. 2 Chambers Street Binghamton, New York 13903-2699 Phone: 607-723-3512 www.mcintoshlabs.com
MC75 60
th
Anniversary
Tube Power Amplier
Owner’s Manual
The lightning ash with arrowhead, within an equilateral
triangle, is intended to alert the user to the presence of
uninsulated “dangerous voltage” within the product’s enclosure that may be of sufcient magnitude to constitute
a risk of electric shock to persons.
The exclamation point within an equilateral triangle is
intended to alert the user to the presence of important
operating and maintenance (servicing) instructions in the
literature accompanying the appliance.
WARNING - TO REDUCE RISK
OF FIRE OR ELECTRICAL
SHOCK, DO NOT EXPOSE
THIS EQUIPMENT TO RAIN OR
MOISTURE.
IMPORTANT SAFETY
INSTRUCTIONS!
PLEASE READ THEM BEFORE
OPERATING THIS EQUIPMENT.
1. Read these instructions.
2. Keep these instructions.
3. Heed all warnings.
4. Follow all instructions.
5. Do not use this apparatus near water.
6. Clean only with a dry cloth.
7. Do not block any ventilation openings. Install
in accordance with the manufacturer’s instructions.
8. Do not install near any heat sources such as
radiators, heat registers, stoves, or other appa-
ratus (including ampliers) that produce heat.
9. Do not defeat the safety purpose of the polarized or grounding-type plug. A polarized plug
has two blades with one wider than the other.
A grounding type plug has two blades and a
NO USER-SERVICEABLE PARTS
INSIDE. REFER SERVICING TO
QUALIFIED PERSONNEL.
third grounding prong. The wide blade or the
third prong are provided for your safety. If
the provided plug does not t into your outlet,
consult an electrician for replacement of the
obsolete outlet.
10. Protect the power cord from being walked on
or pinched particularly at plugs, convenience
receptacles, and the point where they exit
from the apparatus.
11. Only use attachments/accessories specied by
the manufacturer.
12. Use only with the cart, stand, tripod, bracket,
or table specied by the manufacturer, or sold with the apparatus. When a cart is used, use
caution when moving the cart/
apparatus combination to avoid
injury from tip-over.
13. Unplug this apparatus during lightning storms
or when unused for long periods of time.
14. Refer all servicing to qualied service personnel. Servicing is required when the apparatus
has been damaged in any way, such as power-
To prevent the risk of electric
shock, do not remove cover or
back. No user-serviceable parts
inside.
supply cord or plug is damaged, liquid has
been spilled or objects have fallen into the
apparatus, the apparatus has been exposed to
rain or moisture, does not operate normally, or
has been dropped.
15. Do not expose this equipment to dripping or
splashing and ensure that no objects lled
with liquids, such as vases, are placed on the
equipment.
16. To completely disconnect this equipment from
the a.c. mains, disconnect the power supply
cord plug from the a.c. receptacle.
17. The mains plug of the power supply cord shall
remain readily operable.
18. Do not expose batteries to excessive heat such
as sunshine, re or the like.
19. Connect mains power supply cord only to a
mains socket outlet with a protective earthing
connection.
2
IMPORTANT!
INSTRUCTIONS FOR REMOVAL
OF FOAM INSERT OVER THE
VACUUM TUBES PRIOR TO
CONNECTING THE A.C. POWER
SUPPLY CORD, START ON THE
NEXT PAGE.
3
Unpacking the MC75
Caution: To prevent damage to the MC75
Tubes during shipping, there is a
special foam insert surrounding the
Tubes of the Power Amplifier.
The Foam Insert must be
removed from the MC75 before connecting the AC Power Supply Cord to the power
amplif ier.
Failure to do so has the po-
tential of a Fire Hazard,
resulting in damage to the
MC75 and the surrounding
user serviceable parts, including the tubes. If
repairs are needed they must be performed by
an authorized McIntosh Service Agency.
1. Orient the MC75 so the Front is facing you and
remove the Warning Sheet. Refer to figure 1.
2. Using a Philips Head #2 screw driver, remove the
Tube Cover Screw securing the Tube Cover to the
chassis on each side of the MC75. Refer to figure
2. Carefully lift up and remove the Tube Cover
from the MC75. Refer to figure 3.
3. Place the Tube Cover and the previously removed
chassis screws in a safe location, as the Tube
Cover will be reinstalled.
4. Carefully lift up and remove the Foam Insert from
the MC75 exposing the Tubes. Refer to figures 4
and 5.
5. Carefully reinstall the previously removed Tube
Cover using a Tube Cover Screw on each side of
the MC75. Refer to figures 6, 7A, 7B and 8.
Note: Only use the chassis screws supplied with the
MC75. If you can not find the chassis screws,
contact the McIntosh Parts Department for
replacements.
6. Save the Foam Insert and Warning Sheet with the
MC75 Shipping Carton for possible future use.
environment.
Follow these instructions for
removal of the packing foam
before connecting the AC
Power Supply Cord to the
MC75.
In order to remove the foam insert surrounding the tubes on the MC75, it is necessary
to temporarily remove the Tube Cover. After
the foam insert is removed, the Tube Cover is
re-installed and should not be removed. The
cover provides protection from the hazardous
voltages inside the MC75. The MC75 has no
4
Tube Cover
Tube Cover
Tube Cover
Screw
WARNING
TO AVOID A FIRE HAZARD, THE FOAM INSERT
OVER THE VACUUM TUBES MUST BE REMOVED
PRIOR TO CONNECTING THE A.C. MAINS POWER
SUPPLY CORD AND OPERATING THIS PRODUCT.
REFER TO PAGE 3 IN THE MC75 OWNER’S
MANUAL FOR INSTRUCTIONS.
Figure 1
Figure 2
Remove Foam
Insert located
under the Tube
Cover
Remove the
Warning Sheet
Tube Cover
Tube Cover
Screw
Unpacking the MC75 and Ventilation
Figure 3
Figure 4
Foam Insert
Figure 6
Figure 7A
Figure 8
Ventilation
Adequate ventilation extends the trouble free life
of the MC75. Always allow air to f low through the
ventilation holes on the bottom of the amplifier and a
means for the warm air to escape at the top. Refer to
figure 9.
Allow at least 12 inches (30.48cm) above the top;
4 inches (10.16cm) for the Front, Rear and Sides; and
1/2 inches (1.27cm) below the Power Amplifier so the
airf low is not obstucted.
Warm Air
Figure 5
Tube Cover
Screw
Figure 7B
Tube Cover
Screw
Cool Air
Figure 9
5
Loading...