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OPERATING TIPS

The following recommendations will help obtain the best

performance from the oscilloscope.

1.

Always use the probe ground clips for best results,

attached to a circuit ground point near the point of
measurement. Do not rely solely on an external ground
wire in lieu of the probe ground clips as undesired
signals may be introduced.

2.

Avoid the following operating conditions:

a. Direct sunlight.

b. High temperature and humidity.

c. Mechanical vibration.

d. Electrical noise and strong magnetic fields, such as

near large motors, power supplies, transformers,
etc.

3.

Occasionally check trace rotation, probe compensa-

tion, and calibration accuracy of the oscilloscope using
the procedures found in the MAINTENANCE section
of this manual.

4.

Terminate the output of a signal generator into its

characteristic impedance to minimize ringing, espe-
cially if the signal has fast edges such as square waves
or pulses. For example, the typical 50

output of a

square wave generator should be terminated into an
external 50

terminating load and connected to the

oscilloscope with 50

coaxial cable.

5.

Probe compensation adjustment matches the probe to

the input of the scope. For best results, compensation
should be adjusted initially, then the same probe al-
ways used with the same channel. Probe compensation
should be readjusted when a probe from a different
oscilloscope is used.

INITIAL STARTING PROCEDURE

Until you familiarize yourself with the use of all controls,

the settings given here can be used as a reference point to
obtain a trace on the CRT in preparation for waveform
observation.

1.

Set these controls as follows:

VERTical MODE to CH1.
CH1 AC/GND/DC to GND.
Select AUTO triggering, (HOLD OFF pushed in)
Trigger COUPLING to AC.
Trigger SOURCE 
to CH1.
All POSition controls and INTENSITY control cen-
tered (pointers facing up).
Main Time Base control to 1 mS/div.

Sweep Mode switch to MAIN.

2.

Press the red POWER pushbutton.

3.

A trace should appear on the CRT. Adjust the trace

brightness  with the INTENSITY control, and  the
trace sharpness with the FOCUS control.

NOTE

When viewing audio and low frequency
waveforms below 20 MHz, a better wave-
form may be  obtained by engaging the
20 MHz/100 MHz pushbutton. This limits
the bandwidth to 20 MHz and filters out
high frequency noise and interference. For
waveforms above 20 MHz, the pushbutton
must be released to the 100 MHz position.

SINGLE TRACE DISPLAY

Either channel 1 or channel 2 may be used for single-trace

operation. To observe a waveform on channel 1:

1.

Perform the steps of the “Initial Starting Procedure”.

2.

Connect the probe to the CH 1 (X) input jack.

3.

Connect the probe ground clip to the chassis or com-

mon of the equipment under test. Connect the probe
tip to the point of measurement.

4.

Move the CH1 AC/GND/DC switch out of the GND

position to either DC or AC.

5.

If no waveforms appear, increase the sensitivity by

turning the CH 1 VOLTS/DIV control clockwise to a
position that gives 2 to 6 divisions vertical deflection.

6.

Position the waveform vertically as desired using the

CH1 POSition control.

7.

The display on the CRT may be unsynchronized. Refer

to the “Triggering” paragraphs in this section for pro-
cedures on setting triggering and sweep time controls
to obtain a stable display showing the desired number
of waveforms.

DUAL TRACE DISPLAY

In observing simultaneous waveforms on channel 1 and

2, the waveforms are usually related in frequency, or one of
the waveforms is synchronized to the other, although the
basic frequencies are different. To observe two such related
waveforms simultaneously, perform the following:

1.

Connect probes to both the CH 1 (X) and CH 2 (Y)

input jacks.

2.

Connect the ground clips of the probes to the chassis

or common of the equipment under test. Connect the
tips of the probes to the two points in the circuit where
waveforms are to be measured.

OPERATING INSTRUCTIONS

12

Summary of Contents for 2190B

Page 1: ...100 MHz DUAL TRACE OSCILLOSCOPE BK PRECISION INSTRUCTION MANUAL MODEL 2190B BK PRECISION ...

Page 2: ...et 4 Use the time proven one hand in the pocket technique while handling an instrument probe Be particularly careful to avoid contacting a nearby metal object that could provide a good ground return path 5 When using a probe touch only the insulated portion Never touch the exposed tip portion 6 When testing ac powered equipment remember that ac line voltage is usually present on some power input c...

Page 3: ...l for further precautionary information This symbol appears in the manual where the corresponding information is given Instruction Manual for Model 2190B 100 MHz Dual Trace Oscilloscope 2000 B K Precision Corp 1031 Segovia Circle Placentia CA 92870 BK PRECISION ...

Page 4: ...ing Procedure 12 Single Trace Display 12 Dual Trace Display 12 Triggering 13 Magnified Sweep Operation 15 OPERATING INSTRUCTIONS Continued X Y Operation 15 Video Signal Observation 15 Delayed Sweep Operation 15 Applications Guidebook 16 MAINTENANCE 17 Fuse Replacement 17 Line Voltage Selection 17 Periodic Adjustments 17 Calibration Check 18 Instrument Repair Service 18 APPENDIX 19 Important Consid...

Page 5: ... with X10 MAG assures high frequencies and short duration pulses are displayed with high resolution VERTICAL FEATURES High Sensitivity 5 mV div sensitivity for full bandwidth High sen sitivity 1 mV div and 2 mV div using PULL X5 gain control Calibrated Voltage Measurements Accurate voltage measurements 3 on 10 cali brated ranges from 5 mV div to 5 V div Vertical gain fully adjustable between calib...

Page 6: ...its stable observation of complex pulse trains OTHER FEATURES Bandwidth Limiter Selectable full bandwidth of 100 mHz or limited band width of 20 MHz to filter high frequency noise from low frequency waveforms X Y Operation Channel 1 can be applied as horizontal deflection X axis while channel 2 provides vertical deflection Y axis Built in Probe Adjust Square Wave A 2 V p p 1 kHz square wave genera...

Page 7: ...proximately 500 kHz Polarity Reversal CH 2 invert Maximum Input Voltage 400 V dc ac peak HORIZONTAL AMPLIFIER Input through channel 1 input X Y mode CH 1 X axis CH 2 Y axis Sensitivity Same as vertical channel 2 Input Impedance Same as vertical channel 2 Frequency Response DC to 2 MHz 3 dB X Y Phase Difference 3 or less at 100 kHz Maximum Input Voltage Same as vertical channel 1 SWEEP SYSTEM Opera...

Page 8: ...nominal CH 2 Y Output Output Voltage 50 mV div nominal into 50 ohm load Output Impedance Approximately 50 ohms Frequency Response 20 Hz to 100 MHz 3 dB Intensity Modulation Input Signal TTL level intensity increasing with more positive levels decreased intensity with more negative levels Input Impedance Approximately 50 kΩ Usable Frequency Range DC to 5 MHz Maximum Input Voltage 30 V dc ac peak Po...

Page 9: ...ical calibration VERTICAL CONTROLS 9 VERTical MODE Switch Selects vertical display mode Four position lever switch with the following positions CH1 Displays the channel 1 signal by itself CH2 X Y CH2 displays the channel 2 signal by itself X Y used in conjunction with the X Y control and Trigger SOURCE switch to enable X Y display mode DUAL Displays the channel 1 and channel 2 signals simul taneou...

Page 10: ...hen it is pushed in the two sweeps are alternately displayed one after the other normally used at higher sweep speeds 15 CH2 POSition PULL INVert Control POSition Rotation adjusts vertical position of channel 2 trace In X Y operation rotation adjusts vertical position of X Y display PULL INVert When pushed in the polarity of the channel 2 signal is normal When pulled out the polarity of the channe...

Page 11: ...e delayed sweep X Y Used with the VERTical MODE switch and Trig ger SOURCE switch to select X Y operating mode The channel 1 input becomes the X axis and the channel 2 input becomes the Y axis Trigger source and coupling are disabled in this mode TRIGGERING CONTROLS 26 HOLDOFF PULL NORM TRIG Control HOLDOFF Rotation adjusts holdoff time trigger inhibit period beyond sweep duration When control is ...

Page 12: ...ts a positive going slope and the out position selectsanegative going slopeas triggeringpoint for main sweep 30 EXTernal TRIGger Jack External trigger input for single and dual trace operation REAR PANEL CONTROLS not shown 31 Fuse Holder Line Voltage Selector Contains fuse and selects line voltage 32 Power Cord Receptacle 33 CH 2 Y SIGNAL OUTPUT Jack Output terminal where sample of channel 2 signa...

Page 13: ...veform should result EQUIPMENT PROTECTION PRECAUTIONS The following precautions will help avoid damage to the oscilloscope 1 Never allow a small spot of high brilliance to remain stationary on the screen for more than a few seconds The screen may become permanently burned A spot will occur when the scope is set up for X Y operation and no signal is applied Either reduce the intensity so the spot i...

Page 14: ...in Time Base control to 1 mS div Sweep Mode switch to MAIN 2 Press the red POWER pushbutton 3 A trace should appear on the CRT Adjust the trace brightness with the INTENSITY control and the trace sharpness with the FOCUS control NOTE When viewing audio and low frequency waveforms below 20 MHz a better wave form may be obtained by engaging the 20 MHz 100 MHz pushbutton This limits the bandwidth to ...

Page 15: ...tain a stable jitter free dis play in single trace or dual trace operation The proper settings depend upon the type of waveforms being observed and the type of measurement desired An explanation of the various controls which affect synchronization is given to help you select the proper setting over a wide range of conditions AUTO or NORM Triggering 1 In the AUTO triggering mode PULL NORM TRIG swit...

Page 16: ... direction counterclockwise the triggering threshold shifts to a more negative value When the control is centered the threshold level is set at the approximate average of the signal used as the triggering source Proper adjustment of this control usually synchro nizes the display The TRIG LEVEL control adjusts the start of the sweep to almost any desired point on a waveform On sine wave signals the...

Page 17: ...he Trigger Source and VERTical MODE switches to X Y 2 In this mode channel 1 becomes the X axis input and channel 2 becomes the Y axis input The X and Y positions are now adjusted using the POSition and the channel 2 POSition controls respectively 3 Adjust the amount of vertical Y axis deflection with the CH 2 VOLTS DIV and VARIABLE controls 4 Adjust the amount of horizontal X axis deflection with...

Page 18: ...ase control Because of this the oscilloscope automat ically prevents electrically the DELAY Time Base from being set to a slower sweep speed than the MAIN Time Base For example if the MAIN TimeBase is set to 0 1 ms div the slowest possibleDELAY Time Base sweep speed is also 0 1 ms div even if the control is set slower APPLICATIONS GUIDEBOOK B K Precision offers a Guidebook to Oscilloscopes which d...

Page 19: ...le Pry fuseholder away from receptacle 3 When reinstalling fuseholder be sure that the fuse is installed so that the correct line voltage is selected see LINE VOLTAGE SELECTION LINE VOLTAGE SELECTION To select the desired line voltage simply insert the fuse and fuse holder so that the appropriate voltage is pointed to by the arrow Be sure to use the proper value fuse see label on rear panel PERIOD...

Page 20: ...d only as a general check of calibration accuracy not as a signal source for performing recali bration adjustments a voltage standard calibrated at several steps and of 0 3 or better accuracy is required for calibration adjustments The CAL signal should not be used as a time base standard INSTRUMENT REPAIR SERVICE Because of the specialized skills and test equipment re quired for instrument repair...

Page 21: ...p speed and using X10 magnification For the Model 2190B this sweep rate is 2 ns div A rise time of less than about five divisions at this sweep speed should be calculated Calculated Measurements For observed rise times of less than 11 ns the pulse rise time should be caluclated to eliminate the error introduced by the cascaded oscilloscope rise time Calculate pulse rise time as follows Tpulse Limi...

Page 22: ...amages so the above limitation or exclusion may not apply to you This warranty gives you specific rights and you may also have other rights which vary from state to state SERVICE INFORMATION Warranty Service Please return the product in the original packaging with dated proof of purchase to the address below Clearly state in writing the performance problem and return any leads connectors and acces...

Page 23: ...in the industry Valuable to those with little knowledge of oscilloscopes as well as the experienced technician or engineer who wishes to refresh their memory or explore new uses for oscilloscopes Download your FREE copy from our Web site www bkprecision com ...

Page 24: ... 2000 B K Precision Corp 481 314 9 001 Printed in Taiwan 1031 Segovia Circle Placentia CA 92870 ...

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