Heathkit model IO-105
Dual Trace Oscilloscope
Date Calibrated: _____/_____/_____
Calibration Procedure
✔ Disconnect all external cables, components, and wires from the output terminals.
· All controls and switches are described as labeled on either the instrument or the schematic diagram.
✔ Use an insulated or non-conducting screwdriver when making any front panel internal adjustments.
Ancillary Equipment Needed
Audio Generator
Frequency Counter
VTVM
* * * * * * *
FRONT PANEL INITIAL SETUP
Refer to Figure 2-1
Construction Manual, page 151
Beam and Scale Controls
( ) Adjust the INTENSITY control (R105) to the center of rotation.
( ) Adjust the FOCUS control (R106) to center of rotation.
( ) Adjust the SCALE ILLUM control (R104) to full counter-clockwise (AC OFF).
( ) Adjust the HORIZ POS control (R107) to the center of rotation.
Triggering Controls
( ) Set the EXT–LINE–INT switch (S105) to the INT position
( ) Set the AC–DC switch (S106) to the AC position.
( ) Set the POLARITY (+/–) switch (S109) to the (+) position.
( ) Set the AUTO–NORM switch (S110) to the AUTO position.
Sweep Controls
( ) Set the TIME/CM switch (S104) to the .2 msec position.
( ) Adjust the VARIABLE control (R1010) to full clockwise until it clicks.
( ) Adjust the TRIGGER LEVEL control (R109) to the 3 o’clock position.
( ) Adjust the STABILITY control (R108) to the 12 o’clock position.
Channel Select Controls
[Pull-out Tray]
( ) Pull the X5 MAG switch (S108) to X1 (out) position.
( ) Set the VERT MODE switch (S102) to the CH 1 position.
( ) Set the TRIGGER MODE switch (S103) to the CH 1 position.
Channel 1 Controls
[Pull-out Tray]
( ) Adjust the CH 1 POSITION control (R115) to the center of rotation.
( ) Set the CH 1 VOLTS/CM switch (S202) to the .05 position.
( ) Adjust the CH 1 VERT GAIN control (R211) to full clockwise until it clicks.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the GND position.
( ) Adjust the CH 1 DC BAL control (R411) to be adjusted later.
Channel 2 Controls
[Pull-out Tray]
( ) Adjust the CH 2 POSITION control (R116) to the center of rotation.
( ) Set the CH 2 VOLTS/CM switch (S302) to the .05 position.
( ) Adjust the CH 2 VERT GAIN control (R311) to full clockwise until it clicks.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
( ) Adjust the CH 2 DC BAL control (R412) to be adjusted later.
— — — — — — — —
( ) Set the BLANKING switch (S112) [rear panel] to the EXT position.
* * * * * * *
POWER SUPPLY BOARD SETUP
Refer to Figure 1-1 A
Construction Manual, page 115
( ) Adjust the –15 V control (R809) [right rear] to the center of rotation.
( ) Adjust the +15 V control (R814) [right front] to the center of rotation.
( ) Adjust the GEOMETRY control (R820) [left center] to the center of rotation.
— — — — — — — —
( ) Adjust the TRACE ROTATION control (R103) [PICTORIAL 12-2, page 115] to the center of rotation.
* * * * * * *
DEFLECTION BOARD SETUP
Refer to Figure 1-1 A
Construction Manual, page 115
( ) Adjust the ASTIGMATISM control (R573) [right rear] to the center of rotation.
( ) Adjust the VERTICAL COMPENSATION trimmer (C702) [right center] will be adjusted later.
( ) Adjust the DC TRIGGER control (R710) [right second front] to the center of rotation.
( ) Adjust the INTENSITY ADJ control (R760) [right front] to the center of rotation.
( ) Adjust the X5 GAIN control (R727) [left front] to center of rotation.
( ) Adjust the X—Y GAIN control (R726) [left second front] to center of rotation.
* * * * * * *
CHANNEL 1 VERTICAL PRE-AMP BOARD SETUP
[Pull-out Tray]
Refer to Figure 1-1 B
Construction Manual, page 115
( ) Adjust the CH 1 DC BAL control (R412) [front] will be adjusted later.
( ) Adjust the CH 1 VERT CAL control (R418) [second] to the center of rotation.
( ) Adjust the CH 1 DC LEVEL control (R423) [center] to the 3 o’clock position.
( ) Adjust the CH 1 DC TRIGGER control (R401) [rear] to the center of rotation.
* * * * * * *
CHANNEL 2 VERTICAL PRE-AMP BOARD SETUP
[Pull-out Tray]
Refer to Figure 1-1 B
Construction Manual, page 115
( ) Adjust the CH 2 DC BAL control (R412) [front] will be adjusted later.
( ) Adjust the CH 2 VERT CAL control (R418) [second] to the center of rotation.
( ) Adjust the CH 2 DC LEVEL control (R423) [center] to the 3 o’clock position.
( ) Adjust the CH 2 DC TRIGGER control (R401) [rear] to the center of rotation.
* * * * * * *
HORIZONTAL BOARD SETUP
[left vertical]
Refer to Figure 1-1 C
Construction Manual, page 115
( ) Adjust the SWEEP CAL control (R941) [lower front] to the center of rotation.
( ) Adjust the AUTO ADJ control (R514) [rear] to full clockwise.
( ) Adjust the SWEEP LENGTH control (R943) [lower rear] to the center of rotation.
( ) Adjust the LEVEL ADJ control (R918) [center rear] to the center of rotation.
( ) Adjust the TRIG BAL control (R920) [upper rear] to the center of rotation.
* * * * * * *
CALIBRATION
( ) Position the oscilloscope on the rear panel.
( ) Adjust the SCALE ILLUM control (R104) clockwise until it clicks to the ON position.
( ) Set the VTVM range switch to the 15-volt scale position.
( ) Connect the VTVM common test lead to the oscilloscope’s chassis.
* * * * * * *
+15 Volts Supply Adjustment
Refer to Figure 1-1 B
Construction Manual, page 115
( ) Set the VTVM input switch to the DC+ position.
( ) Connect the VTVM’s probe to lug 7 (yellow wire) of terminal strip BH.
( ) Adjust the +15 V control (R814) [right front] for a reading of +15 volts.
( ) Disconnect probe from terminal strip.
* * * * * * *
–15 Volts Supply Adjustment
( ) Set the VTVM input switch to the DC– position.
( ) Connect the VTVM’s probe to lug 4 (gray wire) of terminal strip BH.
( ) Adjust the +15 V control (R814) [right front] for a reading of –15 volts.
( ) Disconnect probe from terminal strip.
* * * * * * *
Channel 1 DC Bias Adjustment
( ) Connect the VTVM’s probe to the base lead of transistor Q407.
( ) Adjust the CH 1 DC LEVEL control (R423) [center] for a reading of 8 volts.
( ) Disconnect probe from transistor.
* * * * * * *
Channel 2 DC Bias Adjustment
( ) Connect the VTVM’s probe to the base lead of transistor Q407.
( ) Adjust the CH 2 DC LEVEL control (R423) [center] for a reading of 8 volts.
( ) Disconnect probe from transistor.
* * * * * * *
Channel 1 DC Course Balance Adjustment
( ) Connect the VTVM’s probe to the source lead of transistor Q402.
( ) Record source voltage: __________
( ) Disconnect probe from transistor.
( ) Connect the VTVM’s probe to the source lead of transistor Q403.
( ) Adjust the CH 1 DC BAL control (R412) [front] until the two voltages are equal.
( ) Disconnect probe from transistor.
* * * * * * *
Channel 2 DC Course Balance Adjustment
( ) Connect the VTVM’s probe to the source lead of transistor Q402.
( ) Record source voltage: __________
( ) Disconnect probe from transistor.
( ) Connect the VTVM’s probe to the source lead of transistor Q403.
( ) Adjust the CH 2 DC BAL control (R412) [front] until the two voltages are equal.
( ) Disconnect probe from transistor.
* * * * * * *
VERTICAL AND HORIZONTAL AMPLIFIER BALANCE ADJUSTMENTS
Refer to Figure 1-2
Construction Manual, page 133
( ) Position the oscilloscope in an upright position.
( ) Set the VTVM range switch to the 150-volt scale position.
( ) Set the VTVM input switch to the DC+ position.
* * * * * * *
Channel 1 Position Adjustment
( ) ( )1 Connect the VTVM’s probe to lug 7 on the CRT socket.
( ) ( )2 Note the voltage indication: __________ __________.
( ) ( )3 Disconnect probe from lug.
( ) ( )4 Connect the VTVM’s probe to lug 8 on the CRT socket.
( ) ( )5 Note the voltage indication: __________ __________.
( ) ( )6 Adjust the CH 1 POSITION control (R115) until the two indications are equal.
( ) ( )7 Disconnect probe from lug.
· Repeat the above 7 steps until no change is noted.
* * * * * * *
Channel 2 Position Adjustment
( ) ( )1 Connect the VTVM’s probe to lug 10 on the CRT socket.
( ) ( )2 Note the voltage indication: __________ __________.
( ) ( )3 Disconnect probe from lug.
( ) ( )4 Connect the VTVM’s probe to lug 12 on the CRT socket.
( ) ( )5 Note the voltage indication: __________ __________.
( ) ( )6 Adjust the CH 2 POSITION control (R116) until the two indications are equal.
( ) ( )7 Disconnect probe from lug.
· Repeat the above 7 steps until no change is noted.
* * * * * * *
TRACE ADJUSTMENTS
⇒ The INTENSITY control (R105) is located on the front panel, and the INTENSITY ADJ control (R760) is on the deflection circuit board.
( ) Adjust the INTENSITY control (R105) until a spot just appears on the display.
( ) Adjust the CH 1 POSITION control (R115) until the spot appears in the center of the display.
( ) Adjust the HORIZ POS control (R107) until the spot appears in the center of the display.
( ) ( )1 Adjust the INTENSITY control (R105) for a sharp round spot.
( ) ( )2 Adjust the FOCUS control (R106) for a sharp round spot.
( ) ( )3 Adjust the ASTIGMATISM control (R573) [right rear on deflection board ] for a sharp round spot.
· Repeat the above three * steps for the best sharp round spot.
( ) Adjust the STABILITY control (R108) clockwise until a short trace appears on the display.
♦ It may be necessary to increase the intensity of the trace.
( ) Adjust the HORIZ POS control (R107) until the trace is centered on the display.
( ) Adjust the X—Y GAIN control (R726) [left second front on deflection board] until the trace is 8 cm long.
( ) Adjust the STABILITY control (R108) clockwise until the trace disappears — a spot should still be visible.
( ) Set the BLANKING switch (S112) [rear panel] to the INT position.
( ) Adjust the STABILITY control (R108) clockwise until a trace appears.
( ) Adjust the TRACE ROTATION control (R103) [neck of CRT] until the trace is parallel to the graticule lines.
⇒ If the trace cannot be made parallel to the graticule lines, perform the following 9 steps * below.
( )1 Adjust the SCALE ILLUM control (R104) to full counter-clockwise (AC OFF).
( )2 Disconnect the line cord from the AC line voltage.
( )3 Disconnect the yellow wire from lug 3 of TRACE ROTATION control (R103) (D-1).
( )4 An orange wire should still be soldered to lug 3 (S-1).
( )5 An orange wire should be soldered to lug 1 (S-1).
( )6 Solder the yellow wire to lug 1 of TRACE ROTATION control (R103) (S-2).
( )7 Connect the line cord to the AC line voltage.
( )8 Adjust the SCALE ILLUM control (R104) clockwise until it clicks to the ON position.
( )9 Adjust the TRACE ROTATION control (R103) [neck of CRT] until the trace is parallel to the graticule lines.
— — — — — — — —
( ) Adjust the CH 1 POSITION control (R115) until the trace is 1 cm from the top graticule [refer to Figure 1-7, page 139].
( ) ( )1 Adjust the GEOMETRY control (R820) [left center of power supply board] until the trace straightens.
( ) ( )2 Adjust the FOCUS control (R106) for a sharp trace.
( ) ( )3 Adjust the CH 1 POSITION control (R115) until the trace is 1 cm from the top graticule
· Repeat the above 3 steps * until the trace bowing is eliminated.
( ) Adjust the CH 1 POSITION control (R115) until the trace is centered.
( ) Adjust the INTENSITY control (R105) to full clockwise.
( ) Adjust the INTENSITY ADJ control (R760) [right front on deflection board] until the trace is 1 mm thick.
✔ The short lines on the center vertical and horizontal lines are 2 mm apart.
( ) Adjust the INTENSITY control (R105) at a comfortable viewing level.
* * * * * * *
CHANNEL 1 TRIGGERING ADJUSTMENTS
( ) Position the oscilloscope on the rear panel.
* * * * * * *
Channel 1 Fine DC Balance
( ) Adjust the CH 1 VERT GAIN control (R211) to full clockwise.
( ) Adjust the CH 1 POSITION control (R115) until the trace is centered.
( ) Adjust the CH 1 VERT GAIN control (R211) to full counter-clockwise while observing the trace.
Ø If the trace moves perform the following 4 steps * below.
( ) ( )1 Adjust the CH 1 POSITION control (R115) until the trace is centered.
( ) ( )2 Adjust the CH 1 VERT GAIN control (R211) to full clockwise.
( ) ( )3 Adjust the CH 1 DC BAL control (R411) until the trace is centered horizontally.
( ) ( )4 Adjust the CH 1 VERT GAIN control (R211) to full counter-clockwise while observing the trace.
· Repeat the above 4 steps * until the trace does not move.
( ) Adjust the CH 1 VERT GAIN control (R211) to full clockwise.
* * * * * * *
AUTOMATIC TRIGGERING
[Horizontal Circuit Board]
Refer to Figure 1-1 C
Construction Manual, page 115
( ) Adjust the STABILITY control (R108) counter-clockwise until the trace sweep just stops.
⇒ It may be necessary to readjust the STABILITY control (R108) slightly clockwise in the next 3 steps *.
( )1 Adjust the AUTO ADJ control (R514) [rear] counter-clockwise until a trace just starts.
· Note screwdriver blade position.
( )2 Adjust the AUTO ADJ control (R514) [rear] counter-clockwise until the trace just stops.
· Note screwdriver blade position.
( )3 Adjust the AUTO ADJ control (R514) [rear] until the screwdriver position is midway between the two noted positions.
( ) Set the TIME/CM switch (S104) to the 2 msec position.
( ) Adjust the CH 1 POSITION control (R115) until the trace is centered.
♦ DO NOT further adjust the CH 1 POSITION control (R115).
( ) Set the CH 1 VOLTS/CM switch (S202) to the .05 position.
( ) Connect the Frequency Counter input and the square wave output of the Audio Generator together using RG59 coax cables and a BNC T-adapter.
( ) Adjust the Audio Generator frequency to 1 kHz.
( ) Adjust the Audio Generator’s output voltage to .2 volts peak-to-peak (P-P).
( ) Connect a RG58 coax cable to the Audio Generator’s output.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the AC position.
( ) Connect the same cable to the CH 1 input.
* * * * * * *
Normal Triggering
Refer to Figure 1-1 C
Construction Manual, page 115
( ) Set the AUTO–NORM switch (S110) to the NORN position.
( ) Adjust the LEVEL ADJ control (R918) [center rear] to full clockwise.
( ) Adjust the LEVEL ADJ control (R918) [center rear] counter-clockwise until a trace just starts.
· Note screwdriver blade position.
( ) Adjust the LEVEL ADJ control (R918) [center rear] counter-clockwise until the trace just stops.
· Note screwdriver blade position.
( ) Adjust the LEVEL ADJ control (R918) [center rear] until the screwdriver position is midway between the two noted positions.
( ) Set the TRIGGERING POLARITY (+/–) switch (S109) to the (–) position.
( ) Adjust the TRIGGER LEVEL control (R109) to the 12 o’clock position.
( ) Adjust the TRIG BAL control (R920) [upper rear] clockwise until a trace appears.
( ) Adjust the TRIG BAL control (R920) [upper rear] either direction until a trace starts on the horizontal centerline.
( ) Set the TRIGGERING POLARITY (+/–) switch (S109) to the (+) position.
· Trace should start close to the horizontal centerline.
( ) Adjust the LEVEL ADJ control (R918) [center rear] either direction slightly until a trace starts on the horizontal centerline.
( )1 Alternate the TRIGGERING POLARITY (+/–) switch (S109) between the (+) and (–) positions.
( )2 Adjust the LEVEL ADJ control (R918) [center rear] either direction slightly until a trace starts.
· Repeat the above 2 steps * until the trace starts an equal distance from the horizontal centerline in both switch positions.
( )1 Alternate the TRIGGERING POLARITY (+/–) switch (S109) between the (+) and (–) positions.
( )2 Adjust the TRIG BAL control (R920) [upper rear] either direction until a trace starts.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
* * * * * * *
Channel 1 DC Triggering
Refer to Figures 1-1 B & C
Construction Manual, page 115
( ) Set the TRIGGERING POLARITY (+/–) switch (S109) in the (+) position.
( ) Set the TRIGGERING AC–DC switch (S106) to the DC position.
( ) Adjust the DC TRIGGER control (R710) [right second front] to the center of rotation.
( ) Adjust the CH 1 DC TRIGGER control (R401) [rear of CH 1 circuit board] either direction until a trace appears.
( )1 Alternate the TRIGGERING AC–DC switch (S106) between the DC and AC positions.
( )2 Adjust the DC TRIGGER control (R710) [right second front] either direction until a trace starts.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
( ) Set the TRIGGERING AC–DC switch (S106) to the DC position.
( ) Set the TRIGGER MODE switch (S103) to the CH 1 + CH 2 position.
( )1 Alternate the TRIGGERING AC–DC switch (S106) between the DC and AC positions.
( )2 Adjust the DC TRIGGER control (R710) [right second front] either direction until a trace starts.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
* * * * * * *
Channel 2 Triggering Adjustments
Refer to Figures 1-1 B & C
Construction Manual, page 115
( ) Set the TRIGGERING AC–DC switch (S106) to the DC position.
( ) Disconnect the cable from the CH 1 input.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the GND position.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Connect the same cable to the CH 2 input.
* * * * * * *
Channel 2 Fine DC Balance
( ) Adjust the CH 2 VERT GAIN control (R311) to full clockwise until it clicks.
( ) Set the AUTO–NORM switch (S110) to the AUTO position.
( ) Adjust the CH 2 POSITION control (R116) until the trace is centered.
♦ DO NOT further adjust the CH 2 POSITION control (R116).
( ) Adjust the CH 2 VERT GAIN control (R311) to full counter-clockwise while observing the display.
⇒ If the trace moves perform the following 4 steps * below.
( ) ( )1 Adjust the CH 2 POSITION control (R116) until the trace is centered.
( ) ( )2 Adjust the CH 2 VERT GAIN control (R311) to full clockwise.
( ) ( )3 Adjust the CH 2 DC BAL control (R412) until the trace is centered horizontally.
( ) ( )4 Adjust the CH 2 VERT GAIN control (R311) to full counter-clockwise while observing the trace.
· Repeat the above 4 steps * until the trace does not move.
* * * * * * *
Channel 1 + Channel 2 DC Triggering
( ) Adjust the CH 2 VERT GAIN control (R311) to full clockwise.
♦ DO NOT further adjust the CH 2 POSITION control (R116).
( ) Set the CH 2 VOLTS/CM switch (S302) to the 2 position.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Set the AUTO–NORM switch (S110) to the NORN position.
( ) Set the TRIGGERING AC–DC switch (S106) to the DC position.
( ) Adjust the CH 2 DC LEVEL control (R423) [center of CH 2 circuit board] either direction until a trace appears.
( )1 Alternate the TRIGGERING AC–DC switch (S106) between the DC and AC positions.
( )2 Adjust the CH 2 DC LEVEL control (R423) [center of CH 2 circuit board] either direction until a trace appears.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
* * * * * * *
Channel 2 Triggering
( ) Set the TRIGGERING AC–DC switch (S106) to the DC position.
( ) Adjust the CH 2 DC LEVEL control (R423) [center of CH 2 circuit board] either direction until a trace appears.
( )1 Alternate the TRIGGERING AC–DC switch (S106) between the DC and AC positions.
( )2 Adjust the DC TRIGGER control (R710) [right second front on Deflection board] either direction until a trace appears.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
( ) Set the TRIGGERING AC–DC switch (S106) to the AC position.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
( ) Set the POLARITY (+/–) switch (S109) to the (+) position.
( ) Disconnect the cable from the CH 2 input.
* * * * * * *
Channel 1 Calibration
( ) Set the TRIGGER MODE switch (S103) to the CH 1 + CH 2 position.
( ) Set the CH 1 VOLTS/CM switch (S202) to the .05 position.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the AC position.
( ) Connect the same cable to the CH 1 input.
( ) Adjust the CH 1 VERT CAL control (R418) [second on CH 1 Vertical Preamp board] until a 4 cm vertical trace.
( ) Disconnect the cable from the CH 1 input.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the GND position.
* * * * * * *
Channel 2 Calibration
( ) Set the VERT MODE switch (S102) to the CH 2 position.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Set the CH 2 VOLTS/CM switch (S302) to the .05 position.
( ) Connect the same cable to the CH 2 input.
( ) Adjust the CH 2 VERT CAL control (R418) [second on CH 2 Vertical Preamp board] until a 4 cm vertical trace.
( ) Disconnect the cable from the CH 2 input.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
* * * * * * *
X–Y Calibration
( ) Set the VERT MODE switch (S102) to the X–Y position.
( ) Adjust the INTENSITY control (R105) counter-clockwise to decrease spot intensity.
( ) Adjust the CH 2 POSITION control (R116) until the trace is centered.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Adjust the X—Y GAIN control (R726) [left second front on Deflection board] until the dots are 4 cm apart.
* * * * * * *
Sweep Calibration
Refer to Figure 1-1 C
Construction Manual, page 115
( ) Adjust the Audio Generator frequency to 50 kHz.
( ) Set the VERT MODE switch (S102) to the CH 2 position.
( ) Set the TIME/CM switch (S104) to the 20 msec position.
( ) Connect the same cable to the CH 2 input.
( ) Adjust the INTENSITY control (R105) for a comfortable viewing.
( )1 Adjust the SWEEP LENGTH control (R943) [lower rear] until the entire trace is seen in 10 cm.
( )2 Adjust the HORIZ POS control (R107) until the entire trace is seen in 10 cm.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
( ) Adjust the SWEEP CAL control (R941) [lower front] until exactly 15 Hz are seen in 10 cm.
( )1 Adjust the SWEEP LENGTH control (R943) [lower rear] until 10 Hz are seen in 10 cm.
( )2 Adjust the HORIZ POS control (R107) until 10 Hz are seen in 10 cm.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
( ) Set the TIME/CM switch (S104) to the 5 msec position.
( ) Adjust the VERTICAL COMPENSATION trimmer (C702) [right center] until the leading edge of the signal is as square as possible with the least amount of overshoot.
* * * * * * *
X5 Gain Calibration
Refer to Figure 1-1 C
Construction Manual, page 115
( ) Set the TIME/CM switch (S104) to the 20 msec position.
( ) Push the X5 MAG switch (S108) to X5 (in) position.
( )1 Adjust the X5 GAIN control (R727) [left front] until exactly 2 Hz are seen in 10 cm.
.
( )2 Alternate the X5 MAG switch (S108) between the X5 (in) and X1 (out) positions until exactly 2 Hz are seen in 10 cm.
· Repeat the above 2 steps * until the trace starts at the same point in both switch positions.
[Refer to Figure 1-11, Construction Manual, page 139 foldout]
( ) Pull the X5 MAG switch (S108) to X1 (out) position.
( ) Disconnect the cable from the CH 2 input.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
* * * * * * *
INPUT ATTENUATOR COMPENSATION
Refer to Figures 1-12, 1-13, & 1-14
Construction Manual, page 139
( ) Adjust the Audio Generator frequency to 1 kHz.
⇒ Adjust the Audio Generator output voltage to maintain approximately the same trace height throughout the following adjustments.
⇒ Compensation trimmers are referenced below from front to back and top or side
[Refer to PICTORIAL 6-8, Construction Manual, page 65]
( )
* * * * * * *
CH 1 Compensation
( ) Set the VERT MODE switch (S102) to the CH 1 position.
( ) Set the CH 1 VOLTS/CM switch (S202) to the .1 position.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the AC position.
( ) Set the TIME/CM switch (S104) to the 100 msec position.
( ) Connect the same cable to the CH 1 input.
( ) Adjust the HORIZ POS control (R107) until leading edge of trace can be seen.
♦ Adjust the compensation trimmers for channel 1 as described below.
[Refer to photograph, Construction Manual, page 180]
♦ Adjust the Audio Generator output at each switch position for a 4 cm P-P trace.
VOLTS/CM Shield
Switch position Trimmer Position
( ) .1 C208 T-1-4
( ) .2 C210 S-1-4
( ) .5 C202 T-1-2
( ) 1 C209 T-1-3
( ) 2 C211 S-1-3
( ) 5 C206 S-1-2
( ) 10 NONE
( ) 20 NONE
( ) Disconnect the cable from the CH 1 input.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the GND position.
* * * * * * *
CH 2 Compensation
( ) Set the VERT MODE switch (S102) to the CH 2 position.
( ) Set the CH 2 VOLTS/CM switch (S302) to the .1 position.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Connect the same cable to the CH 2 input.
( ) Adjust the HORIZ POS control (R107) until leading edge of trace can be seen.
♦ Adjust the compensation trimmers for channel 2 as described below.
[Refer to photograph, Construction Manual, page 181]
♦ Adjust the Audio Generator output at each switch position for a 4 cm P-P trace.
VOLTS/CM Shield
Switch position Trimmer Position
( ) .1 C308 S-2-4
( ) .2 C310 T-2-4
( ) .5 C302 S-2-2
( ) 1 C309 S-2-3
( ) 2 C311 T-2-3
( ) 5 C306 T-2-2
( ) 10 NONE
( ) 20 NONE
( ) Disconnect the cable from the CH 2 input.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
* * * * * * *
** LOW CAPACITANCE (X10) PROBE **
Refer to Figures 1-12, 1-13, & 1-14
Construction Manual, page 139
⇒ This section only needs to be performed if a Low Capacitance (X10) Probe is to be used with this oscilloscope.
( ) Set the CH 1 VOLTS/CM switch (S202) to the .05 position.
( ) Set the VERT MODE switch (S102) to the CH 1 position.
( ) Set the TRIGGER MODE switch (S103) to the CH 1 position.
( ) Connect the Low Capacitance (X10) Probe to the CH 1 input.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the AC position.
( ) Adjust the Audio Generator frequency for a 1 kHz square wave.
( ) Connect the Low Capacitance (X10) Probe to Audio Generator output.
( ) Adjust the Audio Generator output until a 4 cm P-P trace.
( ) Adjust the probe’s trimmer until the display has the same pattern as in the previous attenuator calibration section.
⇒ DO NOT readjust the probe’s trimmer in the following steps.
♦ Adjust the compensation trimmers for channel 1 as described below.
[Refer to photograph, Construction Manual, page 180]
♦ Adjust the Audio Generator output at each switch position for a 4 cm P-P trace.
VOLTS/CM Shield
Switch position Trimmer Position
( ) 2 C203 T-1-1
( ) 5 C205 S-1-1
( ) Disconnect the Low Capacitance (X10) Probe from the CH 1 input.
( ) Set the CH 1 INPUT (AC–GND–DC) switch (S201) to the GND position.
( ) Set the CH 2 VOLTS/CM switch (S302) to the .05 position.
( ) Set the VERT MODE switch (S102) to the CH 2 position.
( ) Set the TRIGGER MODE switch (S103) to the CH 2 position.
( ) Connect the Low Capacitance (X10) Probe to the CH 2 input.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the AC position.
( ) Adjust the Audio Generator output until a 4 cm P-P trace.
♦ Adjust the compensation trimmers for channel 2 as described below.
[Refer to photograph, Construction Manual, page 181]
♦ Adjust the Audio Generator output at each switch position for a 4 cm P-P trace.
VOLTS/CM Shield
Switch position Trimmer Position
( ) 2 C303 S-2-1
( ) 5 C305 T-2-1
( ) Disconnect the Low Capacitance (X10) Probe from the CH 2 input.
( ) Set the CH 2 INPUT (AC–GND–DC) switch (S301) to the GND position.
* * * * * * *
( ) Disconnect all test leads and cables from the instrument.
( ) Disconnect the line cord from the AC power line.
( ) Calibration procedure is complete.