Infinity BU-80, Service Manual

Amplifier/Subwoofer 

BU-80/BU80E/HTS-10

SAFETY INFORMATION/VERSION DIFFERENCES

Warning

Any person performing service of this unit will be exposed
to hazardous voltages and the risk of electric shock. It is
assumed that any person who removes the amplifier from
this cabinet has been properly trained in protecting against
avoidable injury and shock. Therefore, any service
procedures are to be performed by qualified service
personal ONLY!

Caution

This unit does not have a power switch. Hazardous
voltages are present within the unit whenever it is
plugged in.

Before the amplifier is plugged in, be sure its rated voltage
corresponds to the voltage of the AC power source to be
used. Incorrect voltage could cause damage to the amplifier
when the AC power cord is plugged in. Do not exceed rated
voltage by more than 10%: operation below 90% of rated
voltage will cause poor performance or may shut the unit
off.

List of Safety Components Requiring
Exact Replacements

F1 **

Fuse SLO BLO 0.50A or 1.0A 250V
5 x 20mm.UL approved

See Bulletin (INF2000-02) page 16.

PWRCORD 

SPT-2 or better with polarized plug, UL
approved wired with the hot side to fused
side. Use with factory replacement panel
strain relief only.

T1 **

Transformer. Use only factory
Replacement.

DBR or D001

Bridge diode. Use only factory
replacement.

C1, 2 

3300uF, 50V electrolytic filter caps. Be
sure replacement part is at least the same
working voltage and capacitance rating.
Also the lead spacing is important.
Incorrect spacing may cause premature
failure due to internal cabinet pressure
and vibration.

C6 *

10uF 50V electrolytic radial (BU80 and
HTS-10 version “A”,”B” only)

S53AMI 

Power output module. Use only factory

  or CON101

replacement

Faceplate 

Use only factory replacement

Air leak cover 

Use only factory replacement

CMC1 

Use only factory replacement

L1 

Use only factory replacement

Fuse PCB 

Use only factory replacement

Main PCB 

Use only factory replacement

R29 470 

ohm

 1/4

W METAL OXIDE, non

flammable

Leakage/Resistance Check

Before returning the unit to the customer, perform a leakage
or resistance test as follows:
Leakage Current. Note there is no power switch on this unit.
When the power plug is plugged in, the unit is live. Connect
the unit to its rated power source. Using an ammeter,
measure the current between the neutral side of the AC
supply and chassis ground of the unit under test. if leakage
current exceeds 0.5mA, the unit is defective. Reverse the
polarity of the AC supply and repeat.
Resistance. Measure the resistance from either side of the
line cord to chassis ground. If it is less than 500k ohms, the
unit is defective.

WARNING! DO NOT 

return the unit to the customer if it

fails one of these tests until the problem is located and
corrected.

* 

See 

Service Bulletin (INF2000-01) 

page 15.

** 

See 

Service Bulletin (INF2000-02) 

page 16.

Rev A version 

of the BU-80/HTS-10 subwoofer uses

the following SAFETY PARTS:
#80103 - 

T1 

Power Transformer #4300

#80104 - 

F1 

Line fuse 0.5A 250V T type slo-blo

Rev B version 

of the BU-80/HTS-10 subwoofer uses the

following SAFETY PARTS:
#80127 - 

T1 

Power Transformer #4300F

#80111 - 

F1 

Line fuse 1.0A 250V T type slo-blo

Either 

Rev A 

or 

Rev B 

can be identified by:

The correct fuse rating will be printed on the amplifier
label, also:

BU-80: Rev A version

serial #AM0011-29474 and below;

Rev B version 

serial #AM0011-29475 and

above.

HTS-10: Rev A version 

serial #AM0011-07400

and below;

Rev B version 

serial #AM0011-07401 and

above.

HTS-10 subwoofer only

There is a third version, “C”, with minor internal
differences.

Data for this version is included, and differences are
noted in the manual.
Units can be identified for service as follows:
Amplifier faceplate says “Made in Canada” on the “B”
version.
Amplifier faceplate says “Made in China” on the “C”
version.

BU80E = HTS-10 version, “C”