Agilent Technologies 346A Installation and operation manual

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Document Part Number 00346-90137
Printed in the USAJuly 2001
Agilent Technologies Noise Sources:
346A, 346B, N4000A, and N4001A
(All Serial Numbers)
Installation Note
Instructions for Setting Bias Current
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Notice.
The information contained in this document is subject to change without notice.
Agilent Technologies makes no warranty of any kind with regard to this material, including but not limited
to, the implied warranties of merchantability and fitness for a particular purpose. Agilent Technologies
shall notbe liable forerrors contained herein or for incidentalor consequential damages in connectionwith
the furnishing, performance, or use of this material.
Windows 95 and Windows NT are U.S. registered trademarks of Microsoft Corporation.
© Copyright 2001 Agilent Technologies
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3
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and N4001A
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and
N4001A
A. Introduction
Due to a change of manufacturer of the noise diodes, adjustment of bias current is now necessary to ensure that the
noise source performs within its specified ENR range. This document is supplied with all the following replacement
parts.
CAUTION: Repair or parts replacement of noise sources should NOT be attempted without full
calibration capability and official field calibration software.
This Installation Note applies to the installation of the following replacement parts:
Table 1 Replacement Parts List
Model Replacement Bulkhead Replacement Noise Cartridge
346A Std. 00346-60022 00346-60154
346A Opt. 001 00346-60023 00346-60154
346A Opt. 002 00346-60024 00346-60154
346A Opt. 004 00346-60025 00346-60154
346B Std. 00346-60026 00346-60154
346B Opt. 001 00346-60018 00346-60154
346B Opt. 002 00346-60019 00346-60154
346B Opt. 004 00346-60020 00346-60154
N4000A Std. N4000-60014 00346-60154
N4000A Opt 001 N4000-60015 00346-60154
N4001A Std. N4001-60003 00346-60154
N4001A Opt 001 N4001-60004 00346-60154
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4
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and N4001A
NOTE: This Installation Note also applies to the replacement of the 00346-60001 and N4000-60001 printed
circuit boards. To replace the PC board, please orderthe 00346-60157 (for 346A/B) or N4000-60016
(for N4000A/1A) Replacement PC Board Kit.
The replacement parts listed in Table 1 are tested in the factory to determine the bias current level necessary to ensure
that it meets ENR specification.
For the 346A and 346B, bias levels are determined by installing the appropriate resistorvalue forR7 on the printed
circuit board (Figure 1-00346-60001). The appropriate resistoris supplied with the part.
Replacement Bulkheads for the 346A and 346B have the recommended bias level written on the part.The appropriate
resistor is enclosed in a small envelope. The resistor value and part number are written on the envelope. The
N4000/1A bulkheads are not supplied with an envelopeand resistor. However, the value of the current is marked on
the part.
00346-60154 Replacement Noise Cartridges are used in all the listed models. These parts are labeled with a tracking
number.The appropriate resistor is enclosed in an envelope which is marked with the tracking number of the
cartridge, resistor value, part number and recommended bias current level. Also, the cartridges are shipped with
Installation Note 00346-90024, Attenuator Replacement, in case attenuator tuning is necessary to bring the unit to
within specification. It may be necessary, in rare cases, to replace the attenuator to meet specification.
On the N4000A and N4001A models, the bias is set electronically byusing field calibration software to calibrate the
Noise Source and re-burn the EEPROM.The bias value of current supplied with the Replacement Noise Cartridge is
to be used to program the sensor. The enclosed resistorcan be discarded.
A.1346A/B Replacement Noise Cartridge Installation Instructions:
1.Ensure that the cartridge was shipped with a resistor contained in a small envelope.
2.Ensure that the tracking numberon the cartridge matches the number on the envelope.
3.Ensure that the value of the current marked on the envelope corresponds to the resistor value and partnumber
provided (refer to Table 2).
4.Ensure that the resistor value on the envelope matches the resistor supplied.
5.Ensure that InstallationNote 00346-90024has been provided.
6.Disassemble the Noise Source byremoving the two flat head screws near the output connector and slide the
bulkheadout of the housing.
7.Next, remove the two flat head screws near the BNC connector and slide out the printed circuit board assembly.
8.Remove theold cartridge from the bulkhead and install the replacement cartridge.
Ensure that the tinybellows remains on the attenuator pin.
9.Check the resistor installedin positionR7onthe 00346-60001 printed circuit board; please refer to Figure 1-
00346-60001. If it matches the resistor supplied, it is not necessary to install it in the printed circuit board.
10.Install the supplied resistor inR7position (referto Figure 1- 00346-60001).
11.Reassemble the unit and do a preliminary ENR measurement.
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5
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and N4001A
12. For the 346B, if the ENR is not within specification, refer to the supplied 00346-90024 Installation Note for
instructions on how to tune the attenuator to meet the ENR specification at frequencies above 12 GHz. The 346A
should not require polyiron tuning.
13. Retest ENR after tuning the attenuator.
14. If the ENR is still out of specification, substitute another resistor for R7 from Table 2. Decreasing the bias current
by 10% increases the ENR response by 0.5dB at 10MHz.
15. Retest ENR.
A.2 346A/B Replacement Bulkhead Assembly Installation Instructions:
1. Ensure that the bulkhead was shipped with a small envelope containing a resistor.
2. Ensure that the value of the current marked on the bulkhead matches the value on the envelope.
3. Ensure that the value of the current marked on the envelope corresponds to the resistor value and part number
provided (refer to Table 2).
4. Ensure that the resistor value on the envelope matches the resistor supplied.
5. Disassemble the Noise Source by removing the two flat head screws near the output connector and slide the
bulkhead out of the housing.
6. Remove the two flat head screws near the BNC connector and slide out the printed circuit board assembly.
7. Install the replacement bulkhead.
8. Check the resistor installed (if any) in position R7 on the 00346-60001 printed circuit board; refer to Figure 1-
00346-60001. If it matches the resistor supplied, it is not necessary to install it in the printed circuit board.
9. Install the supplied resistor in R7 position (refer to Figure 1- 00346-60001).
10. Reassemble the unit and perform a preliminary ENR measurement.
11. If the ENR is not meeting specification, substitute another resistor for R7 from Table 2.
Decreasing the bias current by 10% increases the ENR response by 0.5dB at 10MHz.
12. Retest ENR.
A.3 346A/B Replacement Printed Circuit Board Assembly Installation Instructions:
1. Disassemble the Noise Source by removing the two flat head screws near the BNC connector, and slide out the
printed circuit board assembly.
2. R7 is not loaded in the replacement printed circuit board assembly. Install the same value of R7 as in the printed
circuit board being replaced.
3. Install the replacement printed circuit board, reassemble the unit and do a preliminary ENR measurement.
4. If the ENR is not meeting specification, substitute another resistor for R7 from Table 2.
Decreasing the bias current by 10% increases the ENR response by 0.5dB at 10MHz.
5. Retest ENR.
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6
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and N4001A
A.4 N4000A/ N4001A Replacement Noise Cartridge Installation Instructions:
1. Ensure that the cartridge was shipped with a small envelope.
2. Ensure that the value of the current is marked on the envelope (the resistor will not be used).
3. Ensure that Installation Note 00346-90024 has been provided.
4. Disassemble the Noise Source using the procedure in the SNS Series Operating and Service Guide, N4000-
90001.
5. Remove the old cartridge and install the replacement cartridge.
6. Using the field calibration software, set the bias current to the value on the envelope (in mA). Discard the resistor
enclosed.
7. Reassemble the unit and do a preliminary ENR measurement.
8. If the ENR is not within specification, refer to the supplied 00346-90024 Installation Note for instructions on how
to tune the attenuator to meet the ENR specification at frequencies above 12 GHz.
9. Retest ENR after tuning the attenuator.
10. If the ENR is not meeting specification, use the field calibration software to reprogram the bias current using the
values from Table 2.
Decreasing the bias current by 10% increases the ENR response by 0.5dB at 10MHz.
11. Retest ENR.
A.5 N4000A/ N4001A Replacement Bulkhead Assembly Installation Instructions:
1. Ensure that the value of the current is marked on the replacement bulkhead.
2. Disassemble the Noise Source using the procedure in the SNS Series Operating and Service Guide, N4000-
90001.
3. Remove the old bulkhead and install the replacement bulkhead.
4. Using the field calibration software, set the bias current to the value on the bulkhead (in mA).
5. Reassemble the unit and do a preliminary ENR measurement.
6. If the ENR is not meeting specification, use the field calibration software to reprogram the bias current using the
values from Table 2.
Decreasing the bias current by 10% increases the ENR response by 0.5dB at 10MHz.
7. Retest ENR.
A.6 N4000A/ N4001A Replacement Printed Circuit Board Assembly Installation Instructions:
1. Using the field calibration software, determine the bias current applied to the noise diode or use the bias current
value written on the bulkhead.
2. Disassemble the Noise Source using the procedure in the SNS Series Operating and Service Guide, N4000-
90001.
3. Install the replacement printed circuit board.
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7
Agilent Technologies Noise Sources: 346A, 346B, N4000A, and N4001A
4. Reassemble the unit.
5. Using the field calibration software, set the bias current to the original value
6. Perform a preliminary ENR measurement.
7. If the ENR is not meeting specification, use the fieldcalibration software to change the bias setting. Refer to Table
2 for bias current values. Decreasing the bias current increases the ENR response.
8. Retest ENR.
A.7 Printed Circuit Board Assembly Graphic and Resistor List
Table 2 Parts List
1. In addition, replace R6 with 0698-7216 (147 Ohms)
Figure 1- 00346-60001
Current (mA) R7 Ohms R7 Part Number
11 237 0698-3442
12 200 0698-6377
13 162 0757-0405
14 133 0698-7215
15 100 0757-0401
16 75 0698-7209
17 51.1 0757-0394
18 28.7 0698-7199
19 10 0757-0346
20 16210698-7217
R7 R6
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** For Agilent Internal Reference Only **
Manufacturing Part Number
Customer Order Number
Printed in USA July 2001
00346-90137
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com

Artisan Technology Group is your source for quality
new and certied-used/pre-owned equipment
• FAST SHIPPING AND
DELIVERY
• TENS OF THOUSANDS OF
IN-STOCK ITEMS
• EQUIPMENT DEMOS
• HUNDREDS OF
MANUFACTURERS
SUPPORTED
• LEASING/MONTHLY
RENTALS
• ITAR CERTIFIED
SECURE ASSET SOLUTIONS
SERVICE CENTER REPAIRS
Experienced engineers and technicians on staff
at our full-service, in-house repair center
WE BUY USED EQUIPMENT
Sell your excess, underutilized, and idle used equipment
We also offer credit for buy-backs and trade-ins
www.artisantg.com/WeBuyEquipment
REMOTE INSPECTION
Remotely inspect equipment before purchasing with
our interactive website at www.instraview.com
LOOKING FOR MORE INFORMATION?
Visit us on the web at www.artisantg.com for more
information on price quotations, drivers, technical
specications, manuals, and documentation
Contact us: (888) 88-SOURCE | [e-mail] | www.artisantg.com
SM
View
Instra