BU80/HTS-10 rev. "A,B"
A. Power Amp Section
1. Resistance Check
Resistance from O/P of the module to GND should be >30K
(NO LOAD)
Resistance from V+ of the module to V- of the module should read >5k
Resistance from V+ of the module to O/P of the module should read >30K
Resistance from V- of the module to O/P of the module should read >30K
2. Power Up
LED RED
3. D.C. Operation
Voltage measurements (DVM)
Between
+6V
V+
O/P
V-
+15V
S/D
FR
I/P
GND
-15V
And
V-
GND
GND
GND
GND
V-
GND
GND
GND
GND
Should be
Reading
+6.2V
+38.7v
0V
-38.7V
+15.5V
+5.75V
0V
0V
0V
-15.5V
4. Check Switching Frequency
Use scope (EITHER USES AN ISOLATION TRANSFORMER OR ATTACHES THE PROBE TIP TO SPK- and
REFERENCE LEAD TO SPK+)
-Reading /-10%,1Vpp
B. Pre Amp Section
1. Low Level Input Sensitivity
-Set up
Turn level and Low-Pass Pot Fully CW
Generator set at 50mV@43Hz
Signal to Low level input
-Voltage measurements
OP AMP
U1(1)
U1(14)
U1(7)
U1(8)
SPEAKER O/P
342mV
572mV
2.88V
2.63V
13.6V
2. High Level Input Sensitivity
-Set up
Turn level and Lo Pass Pot Fully CW
Set Generator at 507mV@43Hz
Signal to High level input
Voltage measurements 13.6V at speaker output
3. Low-Pass
Set upSet Generator at 100mV@100Hz
Signal to Low level input
Measure voltage at speaker output
Voltage measurements
Low-Pass Pot Setting
Output
CW
6.92V
CCW
3.53V
4. LED
With a 35mV input signal at a single Low level input, LED should change to green
See flow chart (following page) for detailed diagnostics.
12
