Tektronix P6248 User manual

Service Manual
P6248
1.7 GHz (Typical)
Differential Probe
071-0573-03
*P071057303*
071057303
Warning
The servicing instructions are for use by qualified
personnel only. To avoid personal injury, do not
perform any servicing unless you are qualified to
do so. Refer to all safety summaries prior to
performing service.

Copyright ©Tektronix, Inc. All rights reserved.
Tektronix products are covered by U.S. and foreign patents, issued and pending. Information in this publication supercedes
that in all previously published material. Specifications and price change privileges reserved.
Tektronix, Inc., P.O. Box 500, Beaverton, OR 97077
TEKTRONIX, TEK, and TEKPROBE are registered trademarks of Tektronix, Inc.
KlipChip, TwinFoot, TwinTip, and VariTip are trademarks of Tektronix, Inc.

WARRANTY
Tektronix warrants that the products that it manufactures and sells will be free from defects in materials and workmanship
for a period of one (1) year from the date of shipment. If a product proves defective during this warranty period, Tektronix,
at its option, either will repair the defective product without charge for parts and labor, or will provide a replacement in
exchange for the defective product.
In order to obtain service under this warranty, Customer must notify Tektronix of the defect before the expiration of the
warranty period and make suitable arrangements for the performance of service. Customer shall be responsible for
packaging and shipping the defective product to the service center designated by Tektronix, with shipping charges prepaid.
Tektronix shall pay for the return of the product to Customer if the shipment is to a location within the country in which the
Tektronix service center is located. Customer shall be responsible for paying all shipping charges, duties, taxes, and any
other charges for products returned to any other locations.
This warranty shall not apply to any defect, failure or damage caused by improper use or improper or inadequate
maintenance and care. Tektronix shall not be obligated to furnish service under this warranty a) to repair damage resulting
from attempts by personnel other than Tektronix representatives to install, repair or service the product; b) to repair
damage resulting from improper use or connection to incompatible equipment; c) to repair any damage or malfunction
caused by the use of non-Tektronix supplies; or d) to service a product that has been modified or integrated with other
products when the effect of such modification or integration increases the time or difficulty of servicing the product.
THIS WARRANTY IS GIVEN BY TEKTRONIX IN LIEU OF ANY OTHER WARRANTIES, EXPRESS OR
IMPLIED. TEKTRONIX AND ITS VENDORS DISCLAIM ANY IMPLIED WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. TEKTRONIX’ RESPONSIBILITY TO
REPAIR OR REPLACE DEFECTIVE PRODUCTS IS THE SOLE AND EXCLUSIVE REMEDY PROVIDED TO
THE CUSTOMER FOR BREACH OF THIS WARRANTY. TEKTRONIX AND ITS VENDORS WILL NOT BE
LIABLE FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES IRRESPECTIVE
OF WHETHER TEKTRONIX OR THE VENDOR HAS ADVANCE NOTICE OF THE POSSIBILITY OF SUCH
DAMAGES.

P6248 1.7 GHz Differential Probe Service Manual i
Table of Contents
General Safety Summary iii...................................
Service Safety Summary v....................................
Preface vii...................................................
Related Manuals vii.................................................
Contacting Tektronix vii.............................................
Specifications 1.............................................
Warranted Characteristics 1..........................................
Typical Characteristics 2............................................
Nominal Characteristics 4...........................................
Performance Verification 5...................................
Equipment Required 5..............................................
Preparation 6.....................................................
Output Offset Voltage 7.............................................
DC Attenuation Accuracy 8.........................................
Differential Signal Range 9..........................................
Rise Time 11......................................................
Common-Mode Rejection Ratio 14....................................
TEKPROBE Communication (operational check) 16......................
Adjustment Procedures 19.....................................
Equipment Required 19..............................................
Offset (preliminary) 20..............................................
Gain 22...........................................................
Offset (Final) 23...................................................
DC CMRR 23.....................................................
AC CMRR 25.....................................................
Maintenance 27..............................................
Cleaning 27.......................................................
Replacing TEKPROBE Interface Pins 27................................
Removing and Replacing the TEKPROBE Interface Collar 28...............
Options 29..................................................
Replaceable Parts 31..........................................
Appendix A: Alternate Verification Procedures 39.................
Equipment Required 39..............................................
Preparation 40.....................................................
CMRR (Common-Mode Rejection Ratio) 41.............................

Table of Contents
ii P6248 1.7 GHz Differential Probe Service Manual
List of Figures
Figure 1: Typical Common-Mode Rejection Ratio
(÷1and÷10 attenuation) 3...............................
Figure 2: Typical differential input impedance versus frequency 3..
Figure 3: Dimensions of probe head and compensation box 4.......
Figure 4: Setup for the output offset voltage test 7................
Figure 5: Setup for differential-mode tests 9.....................
Figure 6: Test system rise time setup 11..........................
Figure 7: Rise time setup for test system with probe 12.............
Figure 8: Setup for CMRR test 15..............................
Figure 9: Adjustment locations 20...............................
Figure 10: Setup for the offset adjustment 21.....................
Figure 11: Setup for gain adjustment 22.........................
Figure 12: Setup for DC CMRR and AC CMRR adjustments 24.....
Figure 13: Replacing TEKPROBE interface pins 27...............
Figure 14: Replacing the TEKPROBE collar 28...................
Figure 15: P6248 replaceable parts 31...........................
Figure 16: P6248 standard accessories 33........................
Figure 17: P6248 optional accessories 35.........................
Figure 18: Normalizing the setup 41.............................
Figure 19: Setup for the CMRR tests 42..........................

P6248 1.7 GHz Differential Probe Service Manual iii
General Safety Summary
Review the following safety precautions to avoid injury and prevent damage to
this product or any products connected to it. To avoid potential hazards, use this
product only as specified.
Only qualified personnel should perform service procedures.
Connect and Disconnect Properly. Do not connect or disconnect probes or test
leads while they are connected to a voltage source.
Connect and Disconnect Properly. Connect the probe output to the measurement
instrument before connecting the probe to the circuit under test. Disconnect the
probe input and the probe ground from the circuit under test before disconnecting
the probe from the measurement instrument.
Ground the Product. This product is indirectly grounded through the grounding
conductor of the mainframe power cord. To avoid electric shock, the grounding
conductor must be connected to earth ground. Before making connections to the
input or output terminals of the product, ensure that the product is properly
grounded.
Observe All Terminal Ratings. To avoid fire or shock hazard, observe all ratings
and markings on the product. Consult the product manual for further ratings
information before making connections to the product.
Connect the ground lead of the probe to earth ground only.
Do Not Operate Without Covers. Do not operate this product with covers or panels
removed.
Do Not Operate With Suspected Failures. If you suspect there is damage to this
product, have it inspected by qualified service personnel.
Do Not Operate in Wet/Damp Conditions.
Do Not Operate in an Explosive Atmosphere.
Keep Product Surfaces Clean and Dry.
Provide Proper Ventilation. Refer to the manual’s installation instructions for
details on installing the product so it has proper ventilation.
Terms in this Manual. These terms may appear in this manual:
ToAvoidFireor
Personal Injury
Symbols and Terms

General Safety Summary
iv P6248 1.7 GHz Differential Probe Service Manual
WARNING. Warning statements identify conditions or practices that could result
in injury or loss of life.
CAUTION. Caution statements identify conditions or practices that could result in
damage to this product or other property.
Terms on the Product. These terms may appear on the product:
DANGER indicates an injury hazard immediately accessible as you read the
marking.
WARNING indicates an injury hazard not immediately accessible as you read the
marking.
CAUTION indicates a hazard to property including the product.
Symbols on the Product. The following symbols may appear on the product:
CAUTION
Refer to Manual
WARNING
High Voltage
Double
Insulated
Protective Ground
(Earth) Terminal

P6248 1.7 GHz Differential Probe Service Manual v
Service Safety Summary
Only qualified personnel should perform service procedures. Read this Service
Safety Summary and the General Safety Summary before performing any service
procedures.
Do Not Service Alone. Do not perform internal service or adjustments of this
product unless another person capable of rendering first aid and resuscitation is
present.
Use Care When Servicing With Power On. To avoid electric shock, do not touch
exposed connections.

Service Safety Summary
vi P6248 1.7 GHz Differential Probe Service Manual

P6248 1.7 GHz Differential Probe Service Manual vii
Preface
This manual contains specifications and service information for the P6248
differential probe.
Related Manuals
For operating information, refer to the P6248 Instructions (071-0566-XX).
Contacting Tektronix
Phone [phone]*
Address Tektronix, Inc.
Department or name (if known)
14200 SW Karl Braun Drive
P.O. Box 500
Beaverton, OR 97077
USA
Web site www.tektronix.com
Sales support 1-800-833-9200, select option 1*
Service support 1-800-833-9200, select option 2*
Technical support Email: [e-mail]
1-800-833-9200, select option 3*
6:00 a.m. -- 5:00 p.m. Pacific time
*This phone number is toll free in North America. After office hours, please leave a
voice mail message.
Outside North America, contact a Tektronix sales office or distributor; see the
Tektronix web site for a list of offices.

Preface
viii P6248 1.7 GHz Differential Probe Service Manual

P6248 1.7 GHz Differential Probe Service Manual 1
Specifications
The specifications in Tables 1 through 4 apply to a P6248 differential probe
installed on a Tektronix TDS 694C oscilloscope. When the probe is used with
another oscilloscope, the oscilloscope must have an input impedance of 50 Ω.
The probe must have a warm-up period of at least 20 minutes and be in an
environment that does not exceed the limits described in Table 1. Specifications
for the P6248 differential probe fall into three categories: warranted, typical, and
nominal characteristics.
Warranted Characteristics
Warranted characteristics (Table 1) describe guaranteed performance within
tolerance limits or certain type-tested requirements. Warranted characteristics
that have checks in the Performance Verification section are marked with the
nsymbol.
Table 1: Warranted electrical characteristics
Characteristic Description
nDC attenuation accuracy ±2% for input voltages ±750 mV (÷1) and ±7.5 V (÷10)
±5% for input voltages ±850 mV (÷1) and ±8.5 V (÷10)
Maximum non destructive input voltage ±25 V(DC + peak AC) between signal and common of the same channel
nDifferential signal range (DC coupled) ±8.5 V at attenuation setting of ÷10
±850 mV at attenuation setting of ÷1
Common-mode signal range (DC coupled) ±7V
nOutput offset voltage ±10 mV (+20 to +30_C,+68to+86_F)
±50 mV (0 to +50_C,+32to+122_F)
nRise time (probe only) <265 ps
nCommon-mode rejection ratio 45 dB at 1 MHz in ÷10
j
25 dB at 100 MHz in ÷10
2
0
d
B
a
t
5
0
0
M
H
z
i
n
÷
1
0
2
0
d
B
a
t
5
0
0
M
H
z
i
n÷
1
0
18 dB at 1 GHz in ÷10
1
8
d
B
a
t
1
G
H
z
i
n
÷
1
0
60 dB at 1 MHz in ÷1
3
8
d
B
a
t
1
0
0
M
H
z
i
n
÷
1
3
8
d
B
a
t
1
0
0
M
H
z
i
n÷
1
35 dB
a
t 500 MHz in ÷1
3
5
d
B
a
t
5
0
0
M
H
z
i
n
÷
1
30 dB at 1 GHz in ÷1
Bandwidth (probe only) DC to ≥1.5 GHz (-- 3dB)
Temperature Operating: 0 to +50_C(+32to+86_F),
0to+60_C (+32 to +122_F)1(probe head)
Nonoperating: --55 to +75_C (--131 to +167_F)1

Specifications
2P6248 1.7 GHz Differential Probe Service Manual
Table 1: Warranted electrical characteristics (cont.)
Characteristic Description
Humidity Operating: 0--90% RH, tested at +30 to +50_ C(+68to+122_F)
Nonoperating: 0--90% RH, tested at +30 to +60_ C (+68 to +140_F)
1See warning that follows.
WARNING. To avoid a burn hazard at high ambient temperatures, do not touch
the probe with bare hands at operating temperatures above +50_C (+122_F)
or at nonoperating temperatures above +70_C (+158_F). Allow sufficient time
for the probe to cool before handling.
Typical Characteristics
Typical characteristics (Tables 2 and 3) describe typical but not guaranteed
performance.
Table 2: Typical electrical characteristics
Characteristic Description
Differential input resistance, DC coupled 200 kΩ±2%
Common-mode input resistance, DC
coupled
100 kΩ±2%
Differential input capacitance <1 pF at 1 MHz
Common-mode input capacitance <2 pF at 1 MHz
Harmonic distortion ≤1.5% measured using 354 mVRMS (or 1.0 VP-P) output at 100 MHz
Differential offset range ±700 mV (÷1 range)
±7V(÷10 range)
Common mode rejection ratio SeeFigure1
Random noise <50 nVHz
at 100 MHz
Input impedance SeeFigure2
Pass band ripple ≤±0.5 dB to 850 MHz (deviation from a nominal slope)
Bandwidth (probe only) DC to ≥1.7 GHz (-- 3dB) @ ≤27_C(÷1 range)
DC to ≥1.85 GHz (-- 3dB) @ ≤27_C(÷10 range)
Rise time (probe and oscilloscope) <265 ps

Specifications
P6248 1.7 GHz Differential Probe Service Manual 3
Frequency (Hz)
80
60
40
20
00300 M
÷10
÷1
dB
600 M 900 M 1.2 G 1.5 G 1.8 G 2 G
Figure 1: Typical Common-Mode Rejection Ratio (÷1 and ÷10 attenuation)
Frequency (Hz)
Impedance (Ω)
100 k
10 k
1k
100
10
01G500 M250 M 750 M 1 .25 G 1 .50 G 1 .75 G 2 G
Figure 2: Typical differential input impedance versus frequency

Specifications
4P6248 1.7 GHz Differential Probe Service Manual
Table 3: Typical mechanical characteristics
Characteristic Description
Dimensions, input connection 0.63 mm (0.025 in) square pin on 2.54 mm (0.100 in) centers
Dimensions, control box 107 mm ×41 mm ×26 mm (4.2 in ×1.6 in ×1.0 in)
Dimensions, probe head 78 mm ×12 mm ×9.3 mm (3.0 in ×0.47 in ×0.36 in)
Dimensions, output cable 1.2m(47in)
Unit weight (probe only) 160g(5.4oz)
4.2 in
1.0 in
1.6 in
3.0 in
.47 in
.36 in
Figure 3: Dimensions of probe head and compensation box
Nominal Characteristics
Nominal characteristics (Table 4) describe guaranteed traits, but the traits do not
have tolerance limits.
Table 4: Nominal electrical characteristics
Characteristic Description
Input configuration Differential (two inputs, + and -- ), with case ground
Output coupling DC
Attenuation settings ÷1 and ÷10
Termination Terminate output into 50 Ω

P6248 1.7 GHz Differential Probe Service Manual 5
Performance Verification
Use the following procedures to verify the warranted specifications of the P6248
Differential Probe. Before beginning these procedures, refer to page 18 and
photocopy the test record and use it to record the performance test results. The
recommended calibration interval is one year.
These procedures test the following specifications:
HOutput offset voltage
HDC attenuation accuracy
HDifferential signal range
HRise time
HCommon mode rejection ratio
Equipment Required
Table 5 lists the equipment required to perform the performance verification
procedure. The types and quantities of connectors may vary depending on the
specific equipment you use.
NOTE. If you cannot obtain a network analyzer, refer to Appendix A: Alternate
Verification Procedures on page 39 for procedures that do not require a network
analyzer to perform the CMRR tests.
Table 5: Test equipment
Description Minimum requirements Example product
Calibrated DC voltage
source (2 required)
Adjustable from 0 V to ≥17 V.
Outputs must be isolated from
earth ground. DC bench supplies
monitored with DMM are adequate.
Tektronix PS280
DMM (2 required) DC Accuracy ≥0.5% on range to
measure 8.5 V, averaging mode.
Tektronix DMM916
Network analyzer 100 kHz to ≥2 GHz, with cables
and adapters to BNC male
Hewlett-Packard 8753D
Digitizing oscilloscope with
TEKPROBE interface
Fully compatible with TEKPROBE
interface (needed only for function-
al check of the TEKPROBE inter-
face)
Tektronix TDS 500, 600, or
700 series oscilloscope

Performance Verification
6P6248 1.7 GHz Differential Probe Service Manual
Table 5: Test equipment (cont.)
Description Example productMinimum requirements
Oscilloscope with sampling
head
Tektronix 11800 series
oscilloscope with SD-24
TEKPROBE Power Supply Tektronix Type 1103 Tektronix Type 1103
BNC cables (2) 50 Ω,42inch 012-0057-01
SMA cables (2) 50 Ω015-0562-00
Banana-to-banana patch
cords (3)
2red
1black
012-0031-00
012-0039-00
Adapter (3) Dual-male-banana-to-female BNC 103-0090-00
Adapter (2) BNC male to dual binding post 103-0035-00
0.025” square pins (3) Approximately 0.75 inch long,
smooth, gold plated.
131-1614-00
Precision inline BNC
terminator
50 Ω± 0.1% 011-0129-00
Probe tip adapters
Y-lead
BNC to probe tip
probe ground lead
(included in the standard probe tip
accessory kit)
020-2328-XX
Adapter SMA Male-to-male 015-1011-00
Adapter (2) SMA Female-to-BNC male 015-0572-00
Preparation
Prepare the equipment as follows:
1. Connect the Y-lead adapter to the inputs of the probe and the ground lead to
the probe ground. (For a description of these accessories, refer to the list of
standard accessories on pages 33 and 34.)
2. Attach the probe to the 1103 TekProbe power supply.
3. If necessary, set the line selector of the 1103 power supply to the correct
voltage.
4. Turn on the 1103 power supply.
5. Set the 1103 offset to off (button not illuminated).
6. Allow the probe and test equipment to warm up for 20 minutes at an ambient
temperature of 20_Cto30_C(68_Fto86_F).
Perform the verification procedures in order.

Performance Verification
P6248 1.7 GHz Differential Probe Service Manual 7
Output Offset Voltage
1. Connect the probe as shown in Figure 4.
--+
Digital multimeter
1103
CH 1
input
CH 1
output
Female BNC-to-male
banana adapter
50 Ωprecision
terminator
50 ΩBNC cable
P6248
BNC-to-probe-tip adapter
DM pair for offset test
Figure 4: Setup for the output offset voltage test
2. Set the probe to ÷10 attenuation.
3. Verify that the output voltage is ≤±10 mV.
4. Change the probe attenuation to ÷1.
5. Verify that the output voltage is ≤±10 mV.
6. Keep the output connections for the next procedure (DC attenuation
accuracy).

Performance Verification
8P6248 1.7 GHz Differential Probe Service Manual
DC Attenuation Accuracy
1. Connect the probe input to the Y-lead adapter and then to the DC source.
Monitor the source voltage with the DMM.
2. Set the probe to ÷10 attenuation.
3. Set the input voltage on the DC source to approximately 5 V. Record the
actual voltage as Vin1.
4. Record the output voltage as Vout1.
5. Set the input voltage on the DC source to approximately 1 V. Record the
actual voltage as Vin2.
6. Record the output voltage as Vout2.
7. Calculate the attenuation as follows: (Vin1--V
in2) ÷(Vout1--V out2).
8. Verify that the attenuation is in the range of 9.8 to 10.2.
9. Set input voltage on the DC source to approximately 0.5 V. Record the actual
voltage as Vin1.
10. Change the attenuation to ÷1.
11. Record the output voltage as Vout1.
12. Set input voltage on DC source to approximately 0.1 V. Record the actual
voltage as Vin2.
13. Record the output voltage as Vout2.
14. Calculate the attenuation as follows: (Vin1--V
in2) ÷(Vout1--V out2).
15. Verify that the attenuation is in the range of 0.98 to 1.02.
16. Keep the output connections for the next procedure.