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Vdc and the duty cycle is 50 percent, instantaneously. The input will swing
then the output voltage will be 1V0.5 negative until it goes one diode drop
= 5 Vdc. This is fine as long as the below -Ein, at which time the rec-
dc power supplies input voltage stays at 10 Vdc. What tifier D will start to conduct. During
Barry Halm,
HP New Jersey Division if Ein changes? If Ein increases then the time that the transistor is off,
/
Eout will also increase, unless the the load current is supplied by C
duty cycle is changed. The duty cycle and by L through the rectifier. When
,
"
& \bi' Basic Switching Regulator has to be decreased to bring the the transistor turns on, the rectifier
I, &'&

output down. This is usually accom- is reverse biased and stops conducting.
The series pass regulator is the
plished with a pulse-width modulator This rectifier is called the "catch"
simplest but least efficient method
that tracks the output and controls or "freewheeling" diode.
of regulation. The output is kept
the duty cycle. Therefore, with the
constant by using the series pass
pulse-width modulator, when Ein This is the basic series switching
transistor as a variable resistance
goes above 10 volts the transistor regulator. Any desired voltage less
between the output and input. With
on-time is decreased, which decreases than the input can be obtained by
the advent of high-current, high-
the duty cycle keeping the output varying the on-time or pulse-width
speed, and low forward drop tran-
voltage at 5 volts. This is how the of the transistor. This voltage reg-
sistors, a more efficient means of
switching regulator maintains a con- ulation can be achieved at high
voltage regulation became available.
stant or regulated output voltage, efficiency since the only losses are
by varying the duty cycle. the transistor dissipation during
switching and saturation.

There are some disadvantages in
this circuit, such as the output must
be lower than the input and the
Figure 1. Waveform of series pass transistor
being turned full-on then full-off output is not isolated from the input.
Figure 2. Series pass transistor with
Enter the series switching regulator. filtering added Let us reconfigure the circuit t o
If the series pass transistor is turned obtain isolated and/or higher voltages.
The ac ripple will have a peak-to-
full-on (saturated) then full-off (cut-
peak value of Ein. To smooth the
off), we get the waveform as shown
ripple we add a low-pass filter, L
in Figure 1. The dc or average value
and C as shown in Figure 2. If we
of this waveform is:
select the reactance of L to be much Driven Half-Bridge Converters
greater than the reactance of C, the
Eout = Ein * tl/T
ripple component can be reduced to The basic series switching regulator
a low value. is fine for low dc input voltages and
where t l is the time the transistor
is full-on and T is the switching nonisolated outputs. Now let's look
What about the rectifier D? When at a circuit that can be used for
frequency in time. The ratio of the
the transistor is turned on, the load high dc input voltages, as found in
on-time to the switching frequency
current and charging current for L "off-line" switching supplies, and that
is called the duty cycle. If the on-
and C will flow from Ein through also provides an output voltage that
time is one-half the switching fre-
the transistor. When the transistor is isolated from the input.
quency, the duty cycle will be 50
opens, interrupting the current flow,
percent and the output voltage will
the input of L swings negative since Two basic advantages of switching
equal to 0.5 times the input voltage.
the current i n L cannot change power supplies are small size and
Example, if the input voltage is 10

Pub. No. 5952-0125 @ Hewlett-Packard 1986
WWW.HPARCHIVE.COM
light weight. This is due partly to
the removal of the low frequency
input power transformer, which is
normally the largest and heaviest
component in a power supply. To
eliminate the input transformer, most
switching supplies use the configu-
ration shown in Figure 3. This circuit
allows operation from either a 120V,
60 Hz source or 240V, 50 Hz source.
Figure 6. Half-bridge converter




Figure 5. Half-bridge converter primary
waveforms

formed by Q1, Q2, C1, C2, and T1.
The transistors are driven alternately
between saturation (on) and cut-off
by the drive and steering circuits.
When Q1 is on, the primary current
Figure 3. Dual input configuration for T1 flows from the positive rail
through Q1 and C2 to the negative
With a 240 Vac input, jumper W1 rail. Conversely, when Q2 is on,
is open and the circuit is configured current flows from the positive rail
as a full-wave bridge. The dc "rail to the negative rail through C1 and
Figure 7. Half-bridge converter secondary
voltage" across capacitors C1 and C2 Q2. Note that at this time the current waveforms
is approximately 320 Vdc. has reversed its direction through
the primary of T1. and 7b are the base drive voltage -3
When the primary power source is waveforms for transistors Q1 and
120 Vac, jumper W1 is connected Figures 5a and 5b show the rela- Q2. When either transistor is on,
and the circuit is now configured as tionship of the voltage waveform both primary and secondary current
a half-wave voltage doubler. The dc across Q1 and Q2, while Figure 5c will flow in T1.
rail voltage remains at 320 Vdc. shows the bipolar output waveform
across the primary of T1. Waveform 7c is the dc output voltage
This dc rail voltage of 320 Vdc has waveform of rectifiers D1 and D2.
to be converted to a more usable Note that there is a period of time The waveform goes to some value
voltage, possibly 5 to 18 Vdc, for when both transistors are off and (Ein) when either Q1 or Q2 is on,
?TL or MOS applications. the voltage across T1 is at zero. This and returns to zero when both Q1
period is called "dead-time" and in- and Q2 are off. Ein would be 10
sures that both transistors are never Vdc if the required output voltage
on at the same time. If both Q1 and was 5 Vdc. Remember that the dc
Q2 were on together, a short would or average value of this waveform
be created across the power rail that is Eout, which equals Ein times the
would destroy both transistors. duty-cycle:

To complete the converter, rectifiers Eout = Ein * duty cycle.
and a low-pass filter are added to
Figure 4. Half-bridge converter the secondary of T1 (Figure 6). Recti- Waveforms 7d and 7e represent the
fiers D1 and D2 not only provide forward current of D2 and D1, re-
One method of converting this voltage spectively. Transformer T1 is polar-
the rectification, but also act as "free-
to something more usable is by using ized so that when Q1 is on, D1 is
wheeling diodes" during the time that
t h e half-bridge converter circuit conducting and D2 is reversed biased.
both switching transistors are off.
shodn in Figure 4.
The waveforms in Figure 7 represent
Conversely, when Q2 is on, D2 is
conducting and D1 is reversed biased.
3
The half-bridge converter is so named When either transistor is on, its
the normal waveforms of a 50 percent
because there are only two active associated rectifier will conduct 100
duty cycle converter. Waveform 7a
components in the bridge circuit

2 BENCH BRIEFS MAYlJUNE 1986
WWW.HPARCHIVE.COM
percent of the required load current. they are parallel to each other, so reduced to almost any potential de-
When both transistors are off and each will supply half of the required sired by simply adjusting the turns
no energy is being transferred from load current. ratio of the power transformer T1.
J
1,


' the primary, inductor L1 must supply
the energy required by the load. Some of the advantages of the half- Our next article will discuss fly-back
During this period, both D1 and D2 bridge converter should now be ob- converters and pulse-width control
act as freewheeling diodes and main- vious. The dc output voltage is isolated circuits that control the drive and
tain the current flow in the inductor from the input power line and it steering circuits of our switching
and through the load. When D1 and can be a positive, negative, or floating regulators. 0
D2 are in the freewheeling mode, output. The output voltage can be



Improvements in Programmable Step Attenuators
Lead to Longer Life Ratings
John Minck,
HP Stanford Park Division

Who wouldn't like longer life, higher
repeatability, and a better warranty?
Especially if they involved pro-
grammable step attenuators that have
mechanical moving parts? Now you
get all three.

Research at Hewlett-Packard has
led to significantly improved
lifetime ratings and warranties
for programmable step attenuators
in the H P 8494151617 and
HP 3332011l213 families.
been improved to 0.01 dB (from 0.03), that cover three frequency ranges;
Effective immediately all newly- typical, after five-million cycles-per- dc to 4 GHz, dc to 18 GHz, and dc
shipped HP programmable coaxial section. to 26.5 GHz, and four attenuation
step attenuators belonging to those The new specifications are the result ranges; 1 dB in 1 dB steps, 70, 80,
1
families will have a two-year war- of an in-depth product-improvement 90 and 110 dB in 10 dB steps. The
ranty, double that of previous prod- program aimed at broadening our attenuators are all programmable
ucts. In addition, the minimum life understanding of the physics of sliding via the HP-IB interface bus (IEEE-
rating of the units has been improved contacts, of the wear of the solenoid 488) using the HP 11713A attenuator1
to five-million cycles-per-step, up from and push rods, and the fatigue factor switch driver.
500k cycles. HP defines a step cycle of the switching flippers.
as an in-out-in cycle of each pro- For more information, please contact
grammable pad step. And the atten- The two attenuator families men- your nearest HP sales office.
uation repeatability specification has tioned above consist of 14 models



HELI-COIL Repair Kits for Stripped Threads in Cabinet Frames
Horst Zittlau , The problem turns out to be that out the threads in the frame may
HP Manufacturing when the covers are on very tightly, fail.
there is more force required than
Some HP Customer Service Centers the jacking screw is capable of over- Temporary corrective action has been
have noted that when attempting to coming in order to back the cover taken by inserting HELI-COILS into
remove the top and bottom instrument off. These resistances come from RFI the top and bottom holes of all rear
covers, the top and bottom rear frame bumps, trim strips and mechanical frames at the H P factory. HELI-
holes are being stripped. interferences. As the screw is backed COILS were chosen because:

MAYlJUNE 1986 BENCH BRIEFS 3
WWW.HPARCHIVE.COM
. They have been found to be best
suited in both size and strength
cations for threads put into alu-
minum parts.
HP PIN
in cases where a stronger thread
/1
.
was needed. For the repair of a 6-32 "inch" or 0590-1034 5401-06
a M3.5 x 0.6 "metric" threaded hole, 0590- 1430 5403-3.5
We have used them successfully order one of the following HELI-
to replace damaged threads. COIL insertion kits. These kits For more information,please contact

. They are used in military appli-
contain one HELI-COIL drill, one
HELI-COIL tap, one insertion tool
and 12 inserts.
your nearest Hewlett-Packard sales
office. 0



Service Tip

Should You Clean Solder Flux from High-Impedance
Printed Circuit Boards?
A previous issue of Bench Briefs boards are commonly found in Bench Briefs' article and leave the
contained a n article titled "A Hewlett-Packard's precision volt- flux on all PC boards including high-
Refresher on Removing ICs." In effect, meters, data acquisition units and impedance boards, providing you
that article recommended that solder multiplexers. There is a valid concern are using an RMA type solder
flux not be cleaned from a board that the ultra-high impedance spec- (e.g., RMA-P2). This type of solder
after a hand solder repair operation. ifications of these instruments could has negligible conductance. Do not
be jeopardized by solder flux. use RA, SA, or OA type solder on
What About High-Impedance high-impedance boards.
PC Boards? Hewlett-Packard's
Recommendation For more information on printed
The topic of solder flux removal has
always raised questions when it comes HP recommends that you follow the
circuit board rework and repair pro-
cedures, write to the address on the "3
to high-impedance boards. These procedure outlined in the previous back page of Bench Briefs and request
publication number 5952-0111. 0




Safety- Related 3061N3062A Board Test
Systems
only) will be replaced with new
software, Date Code 2550.
Service Notes
These two HP Board Test Systems All customers that were known to
Service notes from HP relating to may have a potential safety hazard have received Date Code 2527 should
personal safety and possible equip- in which all power t o the device automatically receive the new 2550.
ment damage are of vital importance under test (DUT) is not removed If you have any questions please
to our customers. To make you more when a reset is executed. contact your nearest HP office.
aware of these important notes, they
are printed on paper with a red The problem lies within the Board HP 3065HX and HL Board
border, and the service note number Test Language software (BTL-200) Test Systems
has a "-S" suffix. In order to make Revision F, Date Code 2527; it may
you immediately aware of any po- not recognize a reset. Some of the A safety problem exists in HP 3065HX
tential safety problems, we are high- symptoms that the system has not systems w i t h s e r i a l s below
lighting safety-related service notes reset are: all power to the DUT is 2543A00117, and HP 3065HL systems
here with a brief description of each not removed or the vacuum is not with serials below 2541A00111. The
problem. Also, in order to draw your turned off. problem involves the -5 volt scanner
attention t o safety-related service
notes on the service note order form
at the back of Bench Briefs, each
Product Safety Service Note 3061AI
62A-15A-S provides more infor-
power supply (HP P/N 0950-1787).
This single-board power supply con- 1
tains three heatsinks, at least one
appropriate number is highlighted mation and the notification that the of which is at a potential of 150
by being printed in color. defective software (Date Code 2527 volts with respect to earth ground.

4 BENCH BRIEFS MAYlJUNE 1986
WWW.HPARCHIVE.COM
~- I
Although this power supply is not the power supply board. Please order stalling coaxial and fiber optic cables
immediately accessible from outside Product Safety Service Note 3065- in dropped ceilings and raised floors
the system, it is possible for service 41-S for more information. used as air ducts for a building's
personnel working inside the system heating/cooling system.
to come in contact with it. HP 37203A HP-IB Extender For details, order this note using
the order form on the back page of
A protective shield (HP P/N 03065- Product Safety Service Note 37203A- this issue of Bench Briefs.
04122) has been designed to fit over 9A-S covers special rules for in-


Hewlett- Packard Offers ATS /I 000 Service Training
Two ATS/1000 customer service tailed ATS/lOOO operation and service ister. The 7-day course is listed as
training classes will be available on knowledge coupled with extensive HP 50036 and priced at $3,100. For
July 31, 1986 and October 23, 1986 hands-on lab work. Certain aspects futher information, please contact
at the Hewlett-Packard Automated of the RTE-A and RTE-4 controlling Danny Shewey, ATS/lOOO product
Manufacturing Systems Organization software will be discussed. support manager, (408) 725-8111, or
(AMSO) in Cupertino, CA. Wei Huang, customer service train-
Interested customers should contact ing, (4151960- 5295. 0
The class provides the student de- their HP sales representative to reg-




automatically updates the library on HP 1631AlD LOGIC ANALYZER
1631AID-9. 1631A serials 2540A and below; 1631D
a quarterly schedule. serials 2518A and below. Power supply change
requires new cooling fan.
1631A/D-lO.l631A/Dserials25XXAand below. TRW
The part numbers for the service board connectors may not seat properly.
note microfiche library and subscrip- 1631A/D-11. 1631A serials 2525A and below; 1631D

Need Any Service tion service are: serials 2446A and below. New policy for 1631AID
ROM replacement. Supercedes 1631A/D-1, 1631AI
D-IA, 1631AD/-2, 1631A/D-3 and 1631A-4.
Notes? Library- 5951-6511 HP 3060Al61Al62A AND 3065 BOARD TEST
Subscription service- 5951-6517 SYSTEMS
They're free! 3060A-65. All serials. Directions for changing from
one power/frequency option to another.
Contact your local HP Sales Office 3061 I2A-15A-S. All serials. Notification of potential
Here's the latest listing of service for ordering information. 0 safety hazard.
3061AI62A-16. All serials. Directionsfor changing from
notes. They recommend modifications one powerIfrequency option to another.
to Hewlett-Packard instruments to HP 346AlB NOISE SOURCE 3065-28. All serials. HP 3065 family board test system
cable test procedure.
increase reliability, improve perform- 346A-2. Serials 2336A and below. New center pin &
3065-33. Troubleshooting the "faceless" ASRU.
capacitor assembly to improve reliability.
ance, or extend their usefulness. 3468-6. Serials 2614A and below. New center pin 8
3065C ICLICXIH /HL/HX-40. All serials. Directions for
changing from one power/frequency option to
capacitor assembly to improve performance.
another.
Use the form at the rear of Bench HP 1345A DIGITAL DISPLAY 3065-41-S.3065HX serials 2543A00117 and below;
3065HL serials 2541A001 11 and below. Notification
Briefs to order, free of charge, service 1345A-6. All serials. Installing memory option 704 in a of potential safety hazard.
standard instrument.
notes for several instruments.
HP 3325A SYNTHESIZERIFUNCTION
HP 1349AlD DIGITAL DISPLAY GENERATOR
If you would like to purchase large 1349A ID-2. Serials 2437A00829 and below. Intensity 3325A-19B-S. Serials 2512A19654 and below. Burned
cutoff circuit modification to improve adjustment power supplies linked to improper primary fuse.
quantities of service notes covering range.
a wide range of instruments, or if HP 3335A SYNTHESIZERILEVEL
HP 1630AlDlG LOGIC ANALYZER GENERATOR
you desire a complete history of all 1630A I D IG-9.1630A serials 2515A and below; 1630D 3335A-11. Serials 164OAO3247 and below. Modification
service notes documenting all changes serials 2514A and below; 1630G serials 251O and
A to improve noise performance of Option 001 ovens.
below. Power supply change requires new cooling
to your instruments, Hewlett-Packard fan. HP 3336A IB IC LEVEL GENERATOR
offers a microfiche library for a one 1630A/D/G-10. 1630AIDIG serials 25XXA and below.
3336A/B/C-16B-S. 3336A serials 2513A01253 and
TRW board connectors may not seat properly.
time charge. There is also a microfiche 1630A/D/G-ll. 1630Aserials2511Aand below; 16300
below; 33368 serials 2514A02483 and below: 3336C
serials 2515A01057 and below. Burned power sup-
subscription service available that serials 251 1A and below; 1630G serials 2415A and
plies linked to improper primary fuse.
below. New policy for 1630AIDIG ROM replacement.
Supercedes 163OG-5, 1630G-5A and 1630AID-6.


MAYIJUNE 1986 BENCH BRIEFS 5
WWW.HPARCHIVE.COM
HP 342144 DATA ACQUISITION AND HP 3711A IF/BB RECEIVER HP 3776NB PCM TERMINAL TEST SET
CONTROL UNIT 3711A-0. Service note index. 3776A-13C. All serials. Retrofitting instructions for data
3421A-14. Serials 2338A06935 and below. Improved measurements Option 001.
transient voltage protection circuitry. HP 3712A IFIBB RECEIVER 3776A-18C. Serials 24441100292 and below. Frequency
3712A-0. Service note index. update instructions for data measurement
HP 3456A DIGITAL VOLTMETER Option 001.
3456A-12A. Serials 2015A. Differences between in- HP 3717A 70MHr 3776A-22C. Serials 24441100292 and below. Firmware
struments with fans and without fans. MODULATOR /DEMODULATOR revision to change generated idle code.
3456A-21. Serials 2201A to 2512A17090. Recom- 3717A-0. Service note index. 3776A-236. All serials. 3776 test programs data car-
mended replacement fuses. tridge (HP P/N 03776-10001) modifications-update
HP 3724A BASEBAND ANALYZER to Revision E.
HP 3457A DIGITAL MULTIMETER 3724A-0. Service note index. 3776A-24A. All serials. Inappropriate selection of
3457A-4. Updated calibration sofhvare HP P/N 03457- 3724A-5A. Serials 2251 UOOl7-23271100195, Noise "through PCM" causing errors 31/32 to be displayed
10200. Revision changes from 1.1 to 1.2 measurements in dBrnCO units. while running a measurement.
3776A-26. Serials 26131100457 and below. Preferred
HP 3466A DIGITAL MULTIMETER HP 37308 DOWN CONVERTER replacement of either A13 (processor card) or A14
3466A-4-16.All serials. Identifying input resistance related (memory card).
37306-0. Service note index.
problems. 3776A-27. All serials. Preferred replacement of analog
switch HP P/N 1826-0417.
HP 37368 RF MODULE FOR 37308 DOWN 3776A-28. All serials. Preferredreplacement of capacitor
HP 3468A/8 DIGITAL MULTIMETER CONVERTER HP P/N 0160-4371.
3468A/B-4. All serials. 3468AIB verification program 37366-0. Service note index. 37766-13C. All serials. Retrofitting instructions for data
description.
measurements Option 001.
HP 37378 RF MODULE FOR 37308 DOWN 37768-18C. Serials 24371100642 and below. Frequency
HP 3478A DIGITAL MULTIMETER CONVERTER update instructions for data measurement
3478A-6. All serials. 3478A verification program 37376-0. Service note index. Option 001.
description. 37768-240. All serials. 3776 test programs data car-
HP 37388 RF MODULE tridge (HP P/N 03776-10001) modifications-update
HP 3488A SWITCH/CONTROL UNIT 37386-0. Service note index. to Revision E.
3488A-OA. 3488A ERC change record. 37766-28. Serials 26141101152 and below (including
3488A-4A. Applies to 44470A relay multiplexer HP 37398 RF MODULE FOR 37308 DOWN Option 002). Preferred replacement of either A1 13
module-ERC 2338; 44471A general purpose relay CONVERTER (processor card) or A1 14/A214 (memory card).
module-ERC 2338; 44473A matrix switch 37396-0. Service note index. 37766-29. All serials. Preferred replacement of analog
module-ERC 2338. Recommended resistor re- switch HP P/N 1826-0417.
placement to decrease the power dissipated in the HP 3743A IF AMPLIFIER 37766-30. Serials 2437U00642 and below. Firmware
driver transistors. 3743A-0. Service note index. update to correct echo return loss measurement.
3488A-6. Serials 2240A05760 and below. Replacement 37768-31. All serials. Preferredreplacement of capacitor
of the program ROM (U401)-ERC 2341. HP 3746A SLMS HP P/N 0160-4371.
3488A-7. Applies to 44474A digital 1 0 module-ERC
1
3746A-0. Service note index.
2605 and below. Modification to ensure a known HP 3779BICID PRIMARY MULTIPLEX
3746A-1OA. All Option 013 instruments. Preferred
turn-on condition. ANALYZER
3488A-8. Recommended replacements for connectors. replacement for A41E l .
3746A-17. Serials 25081100797 and below. Prevention 37796-61. Serials between 20401100316 and
of power interrupt problems associated with 21021100346. Modification to correct performance
HP 3562A DYNAMIC SIGNAL ANALYZER test 4-47 (A-A noise with tone +
OD with tone).
HP-856 controllers.
3562A-1. Serials 2501 A00812 and below. Installation 3746A-18. All serials. Preferred replacement for A501. 3779C-29. Serials between 00500 and 00558. Modifi-
of keying plug in W13 connector. 3746A-19. All serials. Preferred replacement for cation to correct intermittent analog selftest fail
3562A-2. Serials 2502A00759 and below. Modification codes S50 to S56.
A31CR4, A31CR5, A31CR6, A40CR91 and
to prevent noise and distortion self-tests from failing. 3779D-34. Serials between 00500 and 00575. Modifi-
A54CR2.
3746A-20. All serials. Preferred replacement for cation to correct intermittent analog selftest fail
HP 3575A GAIN-PHASE METER A681126. codes 550 to 556.
3575A-7. Serials 1450A05237 and below. Recom-
mended replacement BCD interface boards for HP 3747A/B SELECTIVE LEVEL HP 3780A PAlTERN GENERATOWERROR
Option 002 and 003. MEASURING SET DETECTOR
3747AB-0. Service note index. 3780A-278. All serials. Retrofit of Option 101.
HP 3585A SPECTRUM ANALYZER
3585A-10. Serials 2050A04740 and below. Intermittent HP 3757A ACCESS SWITCH HP 37828 ERROR DETECTOR
calibration errors may be due to lack of fiber washer. 3757A-0. Service note index. 37826-10A. Serials 2512U and below. Preferred re-
3585A-11. Serials 2504A0440 and below (approximate). placement of fan.
Overvoltage protection circuit modification to prevent HP 3762A DATA GENERATOR
inadvertent line fuse blows. HP 40628 SEMICONDUCTOR PARAMETRIC
3762A-0. Service note index.
TEST SYSTEM
HP 3586A/B/C SELECTIVE LEVEL METER 40626-2.40626 Serials 2519J00154 and below; 41416
HP 3763A ERROR DETECTOR
3586AIBiC-12.3586A Serials 2509A01337 and below; Serials 2519J00172 and below. Recommended re-
35866 Serials 2510A03958 and below; 3586C 3763A-0. Service note index.
placement ROMs to correct failure of the SMU Test
Serials 2511A01723 and below. Timing problem (Self Test failure) of the DlAG (diagnostics) or
causes HP-I6 failures.
HP 3764A DIGITAL TRANSMISSION
ANALYZER Performance Verification program after a
3764A-4A. Serials 24181100244 and below. Modification Set-bsearch or Set-lsearch (TIS command) is
HP 3708A NOISE AND INTERFERENCE executed.
TEST SET to prevent incorrect AIS and SYNC loss messages
to the 3764A printer /cassette.
3708A-4A. All serials. New adjustment check procedure HP 4191A RF IMPEDANCE ANALYZER
3764A-9A. Serials 24191100686 and below. Firmware
on the noise bandwidth soft constants and 4191A-24. Serials 2515J01507 through 2515J01658.
revisions.
Appendix 6. Defective counter IC replacement.
3708A-6. All serials. Operation verification test 4-17 3764A-16. Serials 261511 and below. (For all options
tolerance change. except Option 010.) Retrofit kit to upgrade the
features (including CCIlT recommendation G.821) HP 4193A VECTOR IMPEDANCE METER
3708A-7. Serials 24141100290 and below. Preferred 4193A-3. Serials 2516J00984 through 2516J01102.
replacement for A306C20 capacitor. on 3764A.
3764A-17. Serials 261511 and below. Retrofit kit to Defective counter IC replacement.
3708A-8. Serials 25151100330 and below. Preferred
replacement for A201 U9 EEPROM and associated upgrade the features (including CCllT recommen-
dation G.821) on 3764A Option 010. HP 4274A MULTI-FREQUENCY LCR METER
+21 V power supply modification.
3764A-18. Serials 25281100857 (STD/002/003), 4274A-27. Serials 2434J02944 through 2515J03098.
HP 3710A IF/BB TRANSMllTER
3710A-21A. Serials 14381101012 and below. Preferred
replacement for A5CR1.
2528U01097 (Option 001) and below. New high
stability clock oscillator assemblies now available.
Defective counter IC replacement.
f-

6 BENCH BRIEFS MAYlJUNE 1986
WWW.HPARCHIVE.COM
HP 4276A LCZ METER HP 6943A MULTIPROGRAMMER HP 54100AlD DIGITIZING OSCILLOSCOPE
4276A-3. Serials 2227J01642 through 2517J01822. EXTENDER 54100AID-2. All serials. Preventing dust accumulation
Defective counter IC replacement. 6942A-14/6943A-6 Serials 2347A and below. Fan on the CRT screen.
speed control board removal. 54100A/D-3. All serials. The 11536A probing tee causes
HP 4277A LCZ METER excessive ringing in the 54001A probe calibration
4277A-7. Serials 2228J01252 through 2515JO1412. HP 8481A POWER SENSOR procedures. Return tee for credit.
Defective counter IC replacement. 8481A-3. All serials. Cartridge replacement instructions. 54100AID-4. All serials. 54001A and 54003A probes
may cause sampler, trigger, trigger qualifier board
HP 4937A TRANSMISSION IMPAIRMENT HP 8484A POWER SENSOR failure.
MEASURING SET 8484A-1. Serials 2349A and below. Modification to 54100A/D-5. Serials 2547A and below. Firmware re-
4937A-1A. Serials 2418 and below. Modification to reduce noise. vision which adds the 5411O firmware features to
D
improve hold circuit operation. the 54100A/D.
4937A-28. Serials 2523A and below. Loop start and HP 8656AlB SIGNAL GENERATOR HP 54110D DIGITIZING OSCILLOSCOPES
mise to ground modification. 8656A-22. All serials. New external covers improve
4937A-3A. Improved carlying handle. 541 1OD-I. All serials. The 11536A probing tee causes
RF shielding.
4937A-4A. Serials 2545A and below. Revision 3.0 excessive ringing in the 54001A probe calibration
86568-1. Serials 2451A and below. New external
software. procedures. Return tee for credit.
covers improve RF shielding.
54110A/D-2. Serials 2613A and below. Firmware re-
86568-2. Serials 2451A and below. Modification to
HP 4951A PROTOCOL ANALYZER vision fixes problems.
improve output stability.
54110A/D-3. All serials. 54001A and 54003A probes
4951 A-18. All serials. Modification to increase servo 86568-3. Serials 2511A and below. Modification to
may cause sampler, trigger, trigger qualifier board
motor speed. improve high frequency loop locking.
failure.
4951A-19. All serials. Improved READlWRlTE 86568-4. Serials 2509A and below. Modification to
multiplexer. reduce FM distortion. HP 54200AlD DIGITIZING OSCILLOSCOPE
4951A-20. All serials. Rerouting ground cable eliminates 54200A/D-3.54200A serials 2511A and below; 54200D
CRT jitter. HP 8662A SYNTHESIZED SIGNAL serials 2513A and below. Trace on power supply
GENERATOR board too close to rear panel.
HP 4953A PROTOCOL ANALYZER 8662A-1 OA. Serials 2424A and below. Modification to 54200A/D-4. All serials. "Keydown power up reset"
4953A-6C. Serials prior to 2522A00626. Preferred add insulators to power supply. clears display problems.
EPROM replacements. 8662A-128. Serials 2424A and below. Modification to 54200AD-5.54200A serials 2617A and below; 54200D
improve low frequency loop performance and elim- serials 2618A and below. Firmware update to im-
HP 4955A PROTOCOL ANALYZER inate intermittent status errors 03/04. prove performance.
4955A-1C. Serials 2319A and below. Firmware upgrade. 8662A-14. Serials 2545A and below. Modification to
eliminate intermittent error 11. HP 54201AlD DIGITIZING OSCILLOSCOPE
HP 5340A FREQUENCY COUNTER 54201A/D-1. 54201A serials 2602A00206 and below;
5340A-178. All serials. Modification to A1 preamp HP 8663A SYNTHESIZED SIGNAL 54201D serials 2602A00173 and below. ROM revi-
assembly to improve performance. GENERATOR sion increases production yields.
5340A-188. All serials. Modification to A2 preamp 8663A-5A. Serials 2419A and below. Modification to
assembly to improve performance. add insulators to power supply. HP 642208 808618087 EMULATOR POD
8663A-68. Serials 2419A and below. Modification to 642208-1. Pod repair number 2521A00227 and below.
HP 5342A MICROWAVE FREQUENCY improve low frequency loop performance and elim- Modifications to prevent improper arbitration of
COUNTER inate intermittent status errors 03/04. HOLD/HLDA and REQUEST/GRANT signals.

7 5342A-288. All serials. Installation of Option 004 DAC
retrofit kit HP P/N 05432-60202.
5342A-358. All serials. Front panel replacement kit
8663A-8. Serials 2552A and below. Modification to
eliminate intermittent error 11. HP 64220C 80C86 EMULATOR POD
6422OC-1. Pod repair number 2521A00127 and below.
HP P/N 05342-60205. HP 8770A ARBITRARY WAVEFORM Modifications to prevent improper arbitration of
SYNTHESIZER HOLD/HLDA and REQUEST/GRANT signals.
HP 5508A MEASUREMENT DISPLAY 8770A-1. Serials 2601A00101 to 2601A00114. A1 8
5508A-1. Serials 2516A01355 and below. Preferred English to metric conversion. HP 642218 808818087 EMULATOR POD
air filter replacement. 642218-1. Pod repair number 2521A00144 and below.
HP 8673C SYNTHESIZED SIGNAL Modifications to prevent improper arbitration of
HP 6010A DC POWER SUPPLY GENERATOR HOLD/HLDA and REQUEST/GRANT signals.
6010A-1. All serials. W7 ribbon cable assembly 8 6 7 3 0 - 4 . Serials 2332A00105, 2332A00106,
replacement. 2332AOO107, 2332A00109, 2332A00110. HP 64221C 80C88 EMULATOR POD
2332A00111, 2332A00115, 2410A00108, 64221C-I. Pod repair number 2521A001 19 and below.
HP 6011A SYSTEM POWER SUPPLY 2410A00112, 2410A00113. 2410A00114. Modifications to prevent improper arbitration of
2410A00116, 2410A00117, 2410A00118, HOLD/HLDA and REQUEST/GRANT signals.
601 1A-2. All serials. A2 control board interchangeability.
241OA00120, 2413A00127, 2413A00128. Incorrect
601 1A-3. All serials. W7 ribbon cable assembly
fuse information. HP 64243AAlAB 68000 EMULATOR POD
replacement.
64243AA-1. Emulation pod repair number 2526A00455
HP 60128 SYSTEM POWER SUPPLY HP 8673D SYNTHESIZED SIGNAL and below. Modification to prevent address bus
GENERATOR malfunction following a DMA handshake.
60128-1. All serials. A2 control board interchangeability.
8673D-4. Serials 2332A00103, 2410A00104 to 64243A8-1. Emulation pod repair number 2526A00165
60128-2. All serials. W7 ribbon cable assembly
241 OAOOlO6. Incorrect fuse information. and below. Modification to prevent address bus
replacement.
rnalfunction following a DMA handshake.
HP 6030A SYSTEM DC POWER SUPPLY HP 10306BlC 80186 INTERFACE MODULE
6030A-2. All serials. W7 ribbon cable assembly 10306B/C-3. All serials. Modification to reduce exces- HP 64244AA 68008 EMULATOR POD
replacement. sive noise on the user cable. 64244AA-1.. Emulation pod repair number 2526A00165
and below. Modification to prevent address bus
HP 6031A AND 6031A OPTION 100 SYSTEM HP 103428 IC BUS PREPROCESSOR malfunction following a DMA handshake.
POWER SUPPLIES 1034281C-2. Serials 2534A only. Sheet metal
6031A-4. All serials. A2 control board interchangeability. modification. HP 64245AAlAB 68010 EMULATOR POD
6031 A-5. All serials. W7 ribbon cable assembly 64245AA-1. Emulation pod repair number 2526A00178
replacement. HP 11729C CARRIER NOISE TEST SET and below. Modification to prevent address bus
11729C-1. Serials 2524A and below. Improved reliability malfunction following a DMA handshake.
HP 6032A AND 6032A OPTION 100 SYSTEM of HP-I8 unlock indication. 64245AB-1. Emulation pod repair number 2526A00139
POWER SUPPLIES and below. Modification to prevent address bus
HP 15425A TESTHEAD malfunction following a DMA handshake.
6032A-3. All serials. A2 control board interchangeability.

-3 6032A-4. All serials. W7 ribbon cable assembly
replacement.
15425A-1. Serials 2606G00221 and above. Instructions
for adaption to HP 41418 DC SourcelMonitor. HP 64253A 280 EMULATOR SUBSYSTEM
64253A-2. Z80 Emulator pod-all serials. Explanation
4 HP 6942A MULTIPROGRAMMER HP 37203A HP-I8 EXTENDER of peripheral interrupt problems during execution of
6942A-13. All serials. Recommended HP-I8 PHI chip 37203A-9A-S. All serials. Elimination of potential safety RETI instructions.
replacement. hazard. HP 70001A MAINFRAME
6942A-14/6943A-6. Serials 2344A and below. Fan 70001A-lA. All serials. HP 70001A mainframe to
speed control board removal.
System I cabinet interlock kit (HP PIN 5061-9061).
1


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