RESISTANCE ANALYSIS OF ANALOG SECTION
Static testing of the analog circuits. Do not plug in the power supply into 120VAC power source until all
resistance readings check out. The values given below are approximated.
SET SW3 TO SQUARE WAVE (refer to top panel
From
To
Circuit
Ohms
Resistance Measured
Pin 11 (U6)
Pin 3 (U10)
Square Wave
VR5 CCW 12.3K
Ω
Pin 11 (U6)
Pin 3 (U10)
Square Wave
VR5 CW 6.7K
Ω
SET SW3 TO TRIANGLE WAVE
From
To
Circuit
Ohms
Resistance Measured
Pin 2 (U6)
Pin 3 (U10)
Triangle Wave
VR5 CCW 14.7K
Ω
Pin 2 (U6)
Pin 3 (U10)
Triangle Wave
VR5 CW 4.7K
Ω
Pin 13 (U6)
Pin 14 (U6)
Triangle Wave
Greater than 1K
Ω
SET SW3 TO SINE WAVE
From
To
Circuit
Ohms
Resistance Measured
Pin 2 (U6)
Pin 3 (U10)
Sine Wave
VR5 CCW 14.7K
Ω
Pin 2 (U6)
Pin 3 (U10)
Sine Wave
VR5 CW 4.7K
Ω
Pin 13 (U6)
Pin 14 (U6)
Sine Wave
200
Ω
Pin 3 (U6)
GND (B1)
Mult
VR8 CCW < 10
Ω
Pin 3 (U6)
GND (B1)
Mult
VR8 CW 100K
Ω
Pin 4 (U6)
+12V (B3)
VCC
Less than 3
Ω
Pin 7 (U6)
-12V (B2)
Fine Freq Adj
VR7 CCW 108.2K
Ω
Pin 7 (U6)
-12V (B2)
Fine Freq Adj
VR7 CW 8.2K
Ω
Pin 12 (U6)
-12V (B2)
GND
Less than 3
Ω
ª
30% CCW - Counter-Clockwise CW - Clockwise
ª
ª
ª
ª
ª
ª
VR8
U10
U6
-31-
1
2
3
4
1
2
3
4
8
7
6
5
5
6
7
8
10
9
11
12
13
14
15
16
Summary of Contents for XK-550K
Page 37: ...SCHEMATIC DIAGRAM ANALOG SECTION 36 ...
Page 50: ...SCHEMATIC DIAGRAM 49 ...