HP 548A Service manual

A ND SERVICE M ANUA AL
LOGIC CLIP
l
HEWLETT |hfi_, PACKARD

CERTIFICATION
Hewlett-Packard Company certifies that this instrument met its published specifications at the time of
shipment from the factory. Hewlett-Packard Company further certifies that its calibration measure-
ments are traceable to the United States National Bureau of Standards, to the extent allowed by the
Bureau’s calibration facility, and to the calibration facilities of other International Standards Organi-
zation members.
WARRANTY AND ASSISTANCE
This Hewlett-Packard product is warranted against defects in materials and workmanship for a period
of one year from the date of shipment except that in the case of certain components listed in Section |
of this manual, the warranty shall be for the specified period. Hewlett-Packard will, at its option, repair
or replace products which prove to be defective during the warranty period provided they are returned
to Hewlett-Packard, and provided the preventive maintenance procedures in this manual are followed.
Repairs necessitated by misuse of the product are not covered by this warranty. NO OTHER WARRAN-
TIES ARE EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, ThHE IMPLIED WARRAN-
TIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. HEWLETT-PACKARD
IS NOT LIABLE FOR CONSEQUENTIAL DAMAGES.
If this product is sold as part of a Hewlett-Packard integrated instrument system, the above warranty
shall not be applicable, and this product shall be covered only by the system warranty.
Service contracts or customer assistance agreements are available for Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service Office. Addresses are pro-
vided at the back of this manual.
010000-A~238

OPERATING AND SERVICE MANUAL
LOGIC CLIP
548A
548A LOGIC CLIP INSTRUCTIONS
Printed: JUN 1977
Manual Part No. 00548-90009
Microfiche Part No. 00548-90010
Printed in U.S.A.

Page 0 Model 548A
AUXILIARY
POWER
CONNECTOR CAUTION
The 30 volts maximum input to the
548A Logic Clip is an absolute value
which must not be exceeded. Any
application of a dc voltage or a
pulse greater than 30 volts may
cause permanent damage not cov-
ered by warranty.
No damge will occur if the 548A is
clipped directly to an integrated
e T circuit with dc voltages up to 30 volts
P — if the clip is removed within 1 minute.
| Test leads should not be used to
make connections to the 548A if
there is any possibility of encoun-
tering a voltage greater than 18 volts
dc. Test lead inductance may cause
noise spikes or pulses in excess of
30 volts and permanently damage
the logic clip.
Figure 1. HP Model 548A Logic Clip

Model 548A Page 1
APPLICATION
The 548A Logic Clip light-emitting-diodes (LED’s) will indicate logic levels on most integrated circuit (IC) logic
families, including TTL, HTL, DTL, CMQOS, and NMOS. It displays, simultaneously, logic levels for all 8, 14 or 16 pins
of a dual in-line IC which operates from a supply of 4 to 18 volts. The clip can test flip-flops, gates, counters, buffers,
adders, and shift registers. All 16 input gates are electronically buffered to minimize loading on any IC being tested.
Sixteen high-efficiency LED’s provide HIGH (LED on) and LOW (LED off) logic level indication. No power supply
connections are necessary; the Logic Clip powers itself from the V. and ground pins of the IC under test.
NOTE: Accidental connection of up to +30 volts on 548A clip pins for a minute will not damage 548A circuits.
SPECIFICATIONS
Input Protection: 30V absolute maximum for one minute.
Input Current: =15 uA maximum over the range of +0.5V to Vsupply - 0-5V.
Supply Voltage: 4 to 18V across any two pins.
Supply Current: 50 mA maximum with 15 LED’s on.
Auxiliary Positive Supply Voltage: +4.5 to +20V applied to connector on top of clip (ground supplied by IC under test).
Supply must be at least 1.5V more positive than any pin on IC under test to prevent drawing power from the IC.
Input Threshold Voltage Range: V55|, x (0.4 + 0.06). Example: at +5Vgypply LED’s will be off below 1.7V and
on above 2.3V.
Logic Family Compatibility: DTL, TTL, HTL, CMOS and NMOS in dual in-line packages up to 16 pins.
Operating Temperature Range: 0 to 55°C.
Indications:
LED Indication
On Pin voltage above threshold or no connection (open)
Off Pin voltage below threshold
Dim Pin voltage pulsating

Page 2 Model 548A
OPERATION (See Photo)
Squeeze the Logic Clip to open the contact jaws and place the clip on the pins of the IC to be tested. Pin-to-pin
contact must be good. The LED’s will indicate the logic level (LED on = logic HIGH and LED off = logic LOW) on
the corresponding IC pin. There are no operating controls or service adjustments on the clip.
OPERATION WITH AUXILIARY POWER SUPPLY
If the IC’s being tested use low voltage (below 4V) or if power may not be drawn from circuit under test, an external
voltage applied to the 548A top terminal (see photo) allows complete use of the clip. Refer to the “Specifications”
for details. An auxiliary power cable is supplied with the clip. NOTE: Input threshold with auxiliary power supply is
nominally 0.4 x (Vgypply - 0.8).
TESTING
If faulty operation of the Logic Clip is suspected, each pin network should be tested. A 4 to 18 volt supply can be used
to check for correct operation. With the supply connected across any two pins, the V¢ LED and the remaining 14
LED’s should light. Ground each pin separately (except the V. LED), and each LED, when that pin is grounded,
should go off. A separate adjustable voltage power supply can be used to check the threshold voltage of each Logic
Clip pin. Test leads can be used for testing provided the applied voltage does not exceed 18V dc maximum.
The threshold voltage which will switch one LED on is variable, and it depends on the IC supply voltage. See the
specifications. Test the threshold by applying a steady monitored supply voltage to a pair of 548A pins (e.g., +5 volts),
and connect a monitored variable threshold test voltage to each LED pin to be tested. Increase the test voltage from
zero and note the threshold voltage (e.g., 1.7 to 2.3 volts) for each LED.
MAINTENANCE
The Logic Clip internal electronics assembly is a single molded part and is not repairable. To obtain other replace-
ment parts, address inquiry to the nearest Hewlett-Packard Sales and Service Office. Give Logic Clip model number
and identify parts by description.

HEWLETT-PACKARD SALES AND SERVICE OFFICES
To obtain servicing information and order replacement parts, contact the nearest Hewlett-Packard Sales and
Service Office in HP Catalog, or contact the nearest regional office.
IN THE UNITED STATES:
CALIFORNIA
3939 Lankershim Blvd.
North Hollywood 91604
GEORGIA
P.O. Box 28234
450 Interstate North
Atlanta 30328
ILLINOIS
5500 Howard Street
Skokie 60076
NEW JERSEY
W. 120 Century Road
Paramus 07652
IN CANADA:
QUEBEC
Hewlett-Packard (Canada) Ltd.
275 Hymus Blvd.
Pointe Claire
IN EUROPE:
SWITZERLAND
Hewlett-Packard (Schweiz) AG
Rue du Bois-du-Lan 7
P.O. Box 85
CH-1217 Meyrin 2 Geneva
IN AFRICA, ASIA, AND AUSTRALIA:
Hewlett-Packard Intercontinental
3200 Hillview Ave.
Palo Alto, California 94304
IN CENTRAL AND SOUTH AMERICA:
Hewlett-Packard Intercontinental
3200 Hillview Ave.
Palo Alto, California 94304

MARUAL CHANGES
CHANGE DATE: Moy 5, 1983 MANUAL DESCRIPTION
This
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aupersedes
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doted
changea,
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INSTRUMENT:
518A
Logle
Clip
¥
.
Operating
and
Service
Monunl
*
#8%
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all
changes
listed
as
"
"
ERRATA,
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* SERIAL
PREFIX:
None
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0
*
DATE
PRINTED:t
JUN
1976
’
" 4P
PART
NO:
00548-90009
:
®
NICROFICHE
KOt
005/8-90010
.
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NN
¢
INDICATES
NEW
OR
REVISED
ITEM
>
INDICATES
ACTION
TG
BE
TAKEN,
ERRATA
Page |, Specificutionst
>Change "Input Voltoge Limit" to the followling:
Input Protection: 30V asbsolute maximum for 1 minute,
>Change "50 mA" for supply current to "55 mAM,
Page 2, Testing:
YAdd the following sentence at the end of the [irst paragraph under Testing
hend} "Test leads caon be used for testing provided the applied voltage
does not exceced 18Y dc moximum,"
(é] HEWLETT
P8 PACKARD

MANUAL
CHANGES
MODEL
%484
(00548-90009)
Page
&
Insert
this
Warning
nfter
the
Certificntfon/Warranty
and
Assistonce
which
is
on
the
inside
{'ront
cover,
WARN ING
This
product
should
be
connected
to
o
power
source
that
is
sufficiently
isolnted
from
the
main
supply
to
prevent
the
risk
of
elnctriec
shack,
To
further
reduce
the
risk
of
eleastric
shock,
refer
to
the
service
manunl
for
the
equipment
under
test
(when
applicable)
nnd
follow
the
manufacturer's
service
and
snfety
precautions
particularly
when
voltoges
exceeding
30
VAMS
or
50°
VDC
are
present,

)
PACKARD
ai
Printed
in
U.S.A.
HEWLETT
|
Manual
Part
No.
00548-90009