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INSTRUCTION MANUAL
MODEL 421
LOG N PERIOD AMPLIFIER
WARRANTY
We warrant each of our products to be free
from defects in material and workmanship. Our
obligation under this warranty is to repair or
replace any instrument or part thereof (except
tubes and batteries) which, within' a year after
shipment, proves defective upon examination.
We will pay domestic surface freight costs.
To exercise this warranty, call your local
field representative or the factory, DDD 216.
795-2666. You will be given assistance and
shipping instructions.
REPAIRSAND RECALIBRATION
Keithley Instruments maintains a complete re-
pair service and standards laboratory in Cleve-
land, and has an authorized field repair
facility in Los Angeles.
To insure prompt repair or recalibration serv-
ice, please contact your local field representa-
tive or the plant directly before returning the
instrument.
Estimates for repairs, normal recalibration?,,
and calibrations traceable to the National Bureau
of Standards are available upon request.
m)DEL 421 IOG n PERIODAMPLIFIER
!lABLE OF CONTENTS
Section Page
1. GEBERAT,
DWCRIPJ!ION. ............ .1-l
l-l. General. ............... .1-l
l-2. Features................l- 1
1-3. Specifications ............. 1-2
l-4. Equipment Shipped. ........... 1-3
2. ..................
OPJSRATION. 2-1
2-l. Front Panel Controls .......... 2-1
2-2. Rear Chassis Controls and Terminals. .. 2-1
2-3. Input Connection ............ 2-2
2-4. Operating Procedures .......... 2-2
z-2. mmping.................2- 2
- . Recording. ............... 2-3
3. CIRCUIT DESCRIFTION.............. 3-l
y-1. General. ................ 3-l
Log n Amplifier Circuit. ........ 3-1
;:;: Period Circuit ............. 3-2
3-4. Power Supply .............. 3-3
4. WU'iTENANCE
.................. 4-l
4-2. Electrometer Tubes ........... k-1
4-6. Calibration of Log n Amplifier ..... 4-1
4-7. Calibration of Period Circuit. ..... 4-Z
5. REPLACEABLEPARTS
............. ..5- 1
5-2. How to Order Parts ........... 5-l
Model 421 Replaceable Parts List .... 5-2
Schematic Diagrem 16298D ........ 5-y
Change Notice last
page
*Yellow Change Notice sheet is included only for instru-
ment modifications affecting the Instruction Manual.
0563 i
vo.3 1-l
GENERALDF!SCRIPmOM MODEL 4211~~) n PERIODAMPLIFIER
GENE@&DESCRIFTION MODEL
421 MG n PERIODAMPLIFIER
l-3. SP.ECIFICAlTONS.
OC.
RANGR Single scale, from lo-l2 to 10m4 empere; positive currents only.
ZFAODRIFT: Less than l/6 decade in 24 hours after a one-hour warmup.
RISE TIME: Seconds to 9C$ of final current value (DAMPINGcontrol at min-
imum setting):
Current Change With No Significant With 5000 pf
Amperes External Capacitance Across Input
10-12 to 1o-ll 3 seconds 6 seconds
10-n to 10-5 1 second 2 seconds
ACCURACY:Within 0.2 decade.
LIKEA.R-LCSRELAlTONSHIp: Within 2s of 11 scale from lo-l2 to 10-5 ampeve
within 5s of full scale from lo-5 to lo-4: ampere.
ouTpuTs: 1) Zero at lo-l2 empere, increasing as 8 negative voltage 10
volts per decade to -80 volts at 10" ampere: up to one mil-
liampere may be drawn.
2) Recorder output of 50 millivolts full scale is supplied for
servo rebalance recorders.
RAITGE: Single scale, from -30 to infinity to +3 seconds.
ACCURACY: 3% at -6 seconds.
SPEED: 3 seconds maximumto 9% of final
RESPONSE value.
TIME: 10 seconds maximum.
FiEEOVETfY
OuTcPum: 1) Minus one volt for -30 second period; zero for Infinite per-
iod; +lO volts for 3-second period.
2) Recorder output of 50 millivolts full scale is supplied for
servo rebeLlance recorders.
FOLARIzINGFOTSNTIAL: +225 volts for ion chambers.
TABLE 1 (Sheet 1). Model 421 Specifications
l-2 0563
MODEL
421 LOGn PERIODAMPLIFIER GEXERAL
DESCRIPTION
CONNEC~RS: Input: Type HN (UG-560/U) receptacle.
+225 volts: Amphenol 80-C receptacle.
All Outputs: Microphone receptacles.
TUBECO- One EA52, one OA2, one CG3, one 12AU7, two 12AX7, one
12~~7, ITOIW 5886, one 6~~6, one 6~~4, two 6x16, one 6~4, one ~Y&JA.
TR4NSISMR COMPLEMENT: One 2~1183, four 2~1381, one 2N1535.
POWER: 105-125 volts or alO-250 volts, 50-60 CPS, 50 watts,
SUPPLIED:. set of six mating plugs.
ACCESSORIES
ACCFSSOFUES AVAILABLE: Model 4102 Input Assembly, two 5886 electrometer
tubes in a plug-in can (replacement spare).
DIMENSIONS: B-314 inches high x 19 inches wide x 12 inches deep.
mxr WEIGIIT: 23 pounds.
TABLE 1 (Sheet 2). yodel 421 Specifications.
1-J+. FxqJnMENT SHIPPED. The Model 421 Log q Period Amplifier is factory-
calibrated and is shipped with all components in place. The shipping carton
also contains the Instruction Manual and a set of six mating input and out-
put plugs.
l-5. REGISTRATION CARD. The registration card is attached to the front cover
of the Instruction Manual. Please fill it out and mail it when you receive
the instrument.
1-6. DAMAGE SHTPMENT. If *he Model 421 is damaged or faulty when received,
IN
follow the instructions given at the back of the ma~lual for reporting the
defect.
0563 l-3
MODEL
421 MG n PERIODAMPLIFIER OPEXKCTON
SECTION 2. OPERATION
2-1. FRONTPANELCONTROIS.
a. ON-OFF. The ON-OFFcontrol is a double-throw toggle switch which turns
the instrument on. The pilot light is directly above the switch.
b. OPERATE SE72
- 10-5 - SET lo-=. In OPERATE position, the switch allows
the log n amplifier to function as a logarithmic micro-microsmmeter. The
switch also allows the amplifier to be oalibrated at two points, 10-5 and
1oJl ampere.
C. SET 10-l-l. The SET lo-11 potentiometer on the front panel adjusts the
log n amplifier to lo-11 ampere when the PPERATE switch is in SET lo-11
position.
d. SET 10-5. The StT 10'5 potentiometer on the front panel adjusts the
log n amplifier to 10-5 ampere when the OPERATE!
switch is in SST 10-5 position.
e. RECOVER. The RECOVER switch shorts out the feedback diode and allows
quick dissipation of spurious charges which sometimes accumulate on the in-
put terminal. It also allows the amplifier to recover quickly from large
overloads.
f. AMPLIFIRR RALANCE 10-12. This potentiometer adjusts the amplifier
SET
balance to read lo-12 ampere on the meter when the RECOVER
switch is depressed.
g. OPERATE-CHiXKw. With this switch in OPERATI? position, the period
circuit is normal with the period input connected to the log n amplifier
output. In the CHECK position, the switch removes the signal from the
W
log n amplifier to the period circuit. When the switch is at CHECK 00, the
period meter should readoo .
h. SEToo. This potentiometer adjusts the period meter to 00 when the
OPERATE-CHECK switch is at CHECKoo.
00
2-2. REARCHASSISCONTROLS
ANDTERMINALS.
a. INPUT. The INPUT is a RN series receptacle, Military type US-560/U
(Amphenol 82-805).
b. +225. A polarizing potential of ~225 volts can be supplied to ion
chambers through an Amphenol %C receptacle.
C. &I V IOG N OUTPUT. Minus 80 volts are developed for full-scale log n
amplifier meter deflection, and one milliampere can be drawn without upset-
ting the circuits, through a microphone-type receptacle (Amphenol 80 PC2F).
d. 50MVMGNOUTHJT. Fifty millivolts are provided for convenient, dir-
ect connection to servo rebalance recorders. The internal resistance is
approximately 50 ohms.
0563 2-l
Ol?ERATION MODEL
421 MG n PERIODAMPLIFIER
e. 10VPERIODOUTKIT. Ten volts are developed by the period circuit
for a +3 second period. One milliampere can be drawn.
f. 50 MV PERIODOUTHJT. Fifty millivolts are provided for convenient,
direct connection to servo rebalance recorders. The internal resistance is
approximately 50 ohms.
g. DAmmG. The damping control slows the response of the log n amp-
lifier. Maximum damping is obtained by rotating the control fully clock-
wise. The control varies the response time over a ten-to-one ratio.
2-3. INHJT COI'TIWTION.
a. The current source should be connected to the INHIT with the high im-
pedance side of the current source associated with the central conductor of
the RN type receptacle. Avoid movements of the cable during measurements,
since spurious input signals will occur caused by capacitance changes and
generation of static charges.
b. The lead-in cable should be Polyethylene-, Polystyrene- or Teflon-
insulated coaxial cable; the plug should have Teflon insulation. For large
cables, Amphenol 82-804 plugs are recorunended; for small cables, Amphenol
82-816 plugs are recoxmnended. During the preparation of the cable and plugs,
it is essential that all high impedance surfaces be kept scrupulously clean
to avoid leakage. With graphite coated cables, it is necessary to avoid
tracking graphite onto the high impedance surfaces of the cut end of the
insulation and onto the Teflon surface of the plug. ,
2-4. OWm moc!EmTREs.
a. Turn on the power switch, After a &minute warmup, check the amp-
lifier balance by depressing the RECOVER switch. The log n meter should
read lo-l2 ampere; if necessary, adjust the meter-pith the AIQLIFIER BALANCE
contra Turn the log n erz"""' to SET 10 and set the log n meter
to lo- il with the SET 10' Check calibration by turning the OPER-
ATS switch to 10-Y position. If necessary, adjust the meter to 10-5 ampere
with the SET 10-5 control.
b. Check the period circuit by putting the OPERATE-CRFCK switch in
DC)
CHECK position.
00 If the period meter does not read-, adjust the SETW
control for the correct reading.
c. Occasionally recheck the calibration of the log n amplifier andthe
period circuit. Adjust if necessary. After warmup, only infrequent adjust-
ments should be necessary.
2-5. DAMPING.
a. The speed of response, or the time constant of the ion chamber and the
log n amplifier, depends upon the speed of response of the circuitry of the
instrument and also upon the capacitance of the current source and its con-
necting cable. Because of the method of negative feedback applied to the
log n amplifier, the significance of the external input capacitance is de-
2-2 0563
MODEL
421 LOGn PERIODAMXIF!ER OPFIRATION
creased; quite large capacitances can be tolerated without greatly increas-
ing response times. Therefore, a cable run from an ion chamber to the in-
strument is permissible.
b. Variable damping of the log n amplifier is provided by the potentio-
meter on the back of the chassis adjacent to the input receptacle. Maximum
damping is obtained by rotating the control fully clockwise. The damping
slows the response of the log n amplifier so that it tends to average the
statistical noise of the ion chamber current and the noise generated in the
input cable. Therefore, when the log n amplifier output is differentiated
in the period circuit, false short periods will not be indicated.
2-6. REWORDING.
a. The log n amplifier and the period circuit both have two outputs: one
for 50-millivolt recorders, and the other for auxiliary panel meters or
controls.
b. Fifty-millivolt recorders are plugged directly into the 50-millivolt
output receptacles. Roth 50-millivolt receptacles are Amphenol 80 FCZF.
The internal impedance is approximately 50 ohms. Resistor dividers for more
sensitive recorders can easily be made at the recorder input.
C. Alarm and remote indicating circuits can easily be connected to the
high-level outputs. Amplifiers and cathode ray oscilloscopes are also con-
nected to the high-level outputs. Terminal No. 1 of each connector is at
ground potential.
2-7. +225 VOLTS. A receptacle has been mounted on the back of the chassis
to provide t225 volts for polarizing an ion chamber. The potential is de-
rived directly from the electronically regulated power supply. The chassis
connector is Amphenol 80 C; the mating plug is Amphenol 80 M.
0563 2-3
MODEL
421 w n PERIODAMPLIFIER CIRCUIT DESCRIPTION
SECTION 3. CIRCUIT DESCRIPTION
3-1. GEFNERAL. The Model 421 contains three principal circuits, the log n
amplifier, the period circuit and the power supply.
NOTE
The circuit designations used In this section refer to the
schematic diagram, 16298D, found at the back of the Manual.
Ixx; n AMPLIFIER PERIODCIRCUIT
FIGUF3 2. Simplified Circuit Diagram of Model 421.
3-2. LOGN AMPLIFIER CIRCUIT,
a, The log n aqlifier is principally a micro-micmatuneter whose logarlth-
mic scale is obtained by negative feedback from output to input through a
diode operated in the velocity field region. The diode used is an ~52 spec-
ial purpose tube.
b. The PA52 offers outstanding advantages in this application:
1. The insulation of the EA52 is of a very high order. Therefore, the
diode plate has very little leakage which would cause erratic effects in
the low current region.
2. Since this tube is an uhf diode, the capacity across it is minimal.
This results in a considerable improvement in response speed over instru-
ments which employ conventional diodes.
0563 3-l
CIFXXIT DESCRIPTION MODEL
421 IOG n PERIODAMPLIFIER
c. The feedback from the output is connected through potentiometer R106 so
that adjusting ~106 will control the potential in series with the output.
This potential is necessary to buck out the voltage across the diode in order
that the log n amplifier output can be kept at ground potential when the in-
put is at ground potential.
d. The amplifier of the log n circuit consists of two 5886 electrometer
tubes, V2 and V3, followed by high gain pentodes, V4 and V5. Feedback from
the cathodes of V4 and V5 to the screens of V2 and V3 stabilizes the plate
potentials of V2 and V3. Additional gain is provided by V6a. VT is a con-
stant-current coupling element between v6a and V6b, which is the cathode fol-
lower output for the log n amplifier. The constant-current coupling element
eliminates attenuation so that the output will develop -80 volts for full-
scale deflection. The output drives the diode feedback circuit, the panel
meter, the high-level and the 50-millivolt outputs plus the period circuit.
The circuit outpu potential is zero for lo-l2 ampere meter indication, and
-80 volts for 10' $ ampere indication. The 50-millivolt output is supplied
through a resistive voltage divider. The open loop gain of the amplifier is
approximately 10,000; the feedback factor is approximately 1000.
e. The calibration circuit consists of a 1.34-volt mercury battery, Bl,
and resistors RlOl, R102, R103 and R104. The log n OPERATE switch Sl is used
to select the desired signal, either 1C-11 or lo-5 ampere.
f. The meter calibration is established by alternating between the 10-l-l
and the 10m5 positions of the OBEFNE switch, which causes lo-11 or 10-5
ampere to flow in the input. The potentiometers Rlll and R106 are adjust d
until these calibration signals read properly on the meter. The SET 10-l?
control, Rlll, adjusts the feedback voltage in series with Vl and thus sets
the static resistance of the diode at one point. The SET 10-5 control, R106,
adjusts the gain of the amplifier and thus ad.justs the change of the diode
voltage with current, so that the remainder of thbscale reads correctly.
Once these adjustments are made, only the SET 10' control needs to be used
to compensate for diode drift. The other controls will require infrequent
adjustment.
g. With the RECOVER switch depressed, the log diode, Vl, is shorted out.
In this condition the logarithmic characteristic of the amplifier is removed
and the ci cuit is simply a linear feedback amplifier whose zero corresponds
to the lo- iEz position on the meter. The AMPLIFIER BALANCE potentiometer R116
adjusts the amplifier zero. With proper balance of the amplifier, dc voltage
at the input will be less than five millivolts in normal operation.
h. Cl01 is the damping capacitor which slows the response of the log n
amplifier. With the low impedance end of Cl01 connected to ground, the re-
sponse is damped the least. As more and more feedback signal from the output
is introduced at the low impedance end of ClOl, the damping is increased.
The damping control, RlOg, increases the feedback voltage until the desired
amount of damping is obtained.
3-3. PERIODCIRCUIT.
a, The period circuit is an operational amplifier connected as a different-
3-2 0563
MODEL
421 LOGn PERIODAMPLIFIER CIRCUIT DESCRIPTION
iator. C201 is the differentiating capacitor and RZOl is placed in series
with the capacitor to lessen response to very high frequencies. The feed-
back resistor R2l.l determines the sensitivity of the period smplifier. RZll
is returned to potentiometer R2Zl so that the feedback factor can be varied.
In this way, the calibration of the period circuit may be adjusted. Capac-
itor C204 slows the circuit response to about one second full scale.
b. The period amplifier consists of balanced 5886 tubes followed by a
12ALl7 tube connected as a differential amplifier. Feedback from the 12AU7
cathodes to the screens of the 5886 tubes stabilizes the operating point of
the 5886 tube plates. Vll, a cathode follower, drives the output meter and
the feedback loop. The open loop gain of the amplifier is approximately 200.
The circuit output is 10 volts for a positive period of three seconds.
c. The CHECK switch S3 in the CHECK
00 position grounds one terminal of
C201 and leaves only the grid of ~8 connected to the feedback resistor.
This condition corresponds to infinite period or no change in output from
the log n amplifier. If the period meter does not point to infinity in this
position, it may be adjusted by ~206.
d. D201 and D202 are zener diodes connected back-to-back to limit the
amplifier input voltage in case of overload. Substantial decrease in recov-
ery tti is provided by these diodes.
3-4. POWER
SUPPLY.
a. The Model 421uses an electronically regulated +Z25 volt supply, a VR
tube regulated -150 volt supply, and a transistorized -12 volt supply.
b. The +225 volt supply utilizes a type 6~6 series tube, Vl3, which is
controlled by a two-stage differential dc amplifier, Vl4 and V17. V17 com-
pares the B plus voltage, sampled via R3l2 and R314, to the voltage of ref-
erence tube ~16. The output of Vl7 is amplified by Vl4 and used to control
the resistance of the series tube V13. The polarizing potential which ap-
pears on the back of the chassis is taken directly from the +2Z5 volt supply.
c. The -150 volt supply is derived from full-wave rectifier V12 and a
conventional RC filter network. The minus supply is derived from a half-
wave rectifier, D301 through D304, and filtered with a three-stage RC filter,
R304 and C3O2, R305 and C303, ~306 and C304, and finally regulated at -150
volts by V15.
d. The log diode filament voltage power supply consists of an ultra-stable
transistor regulator which supplies 12 volts at 1.2 amperes. The regulation
of this power supply is better than 0.005% for a line voltage variation of
100 to 130 volts.
0563 3-3
MODEL
421 LOGn PERIODAMPLIFIi!X MAINTENANCE
SECTION 4. MAINTENANCE
4-l. GERERAL.
a. The Keithley Model 421 Log n Period Amplifier has been designed to give
long, trouble-free service. High quality components have been used through-
out, and the circuits are stabilized by a substantial amount of negative
feedback.
b. The detailed circuit schematic diagram 16298~ is at the back of the
manual. Circuit designations in this section refer to this diagram. Section
3, Circuit Description, contains an explanation of the function of the prin-
cipal circuit components.
4-2. ELEC'PROMETEX
IUBES.
a. Two pairs of electrometer tubes, V2 and V3, ~8 and Vg, are each located
in an aluminum can which plugs onto the top of the chassis. Each can is
labeled Model 4102 Input Tube Assembly. These tubes have been selected,
matched and labeled; the Keithley part number is EV5886-5. It is recommended
that the complete input tube assembly be kept on hand for replacement purposes.
b. A type EA52 electrometer tube, Vl, is used &s the log diode elementi
This t be is tested for logarithmic characteristics over the range of 10
to lo- E ampere. This tube must be selected to operate over this range; order
replacements only through Keithley Instruments.
4-3. INSULATION. All insulation for the high impedance conductors is made
of Teflon, &s are the contact insulators on the log n OPERATE switch. This
should give satisfactory service in all humidities. Occasionally, the high
impedance insulators should be inspected to insure that they are free from
dirt and dust, and they should be brushed off if necessary.
4-b.. CONNECTOR CAP, The cap for the input receptacle should be kept in place
whenever the input is not being used. In storage and in transport, it keeps
the insulation from accumulating dust, dirt and moisture. Before screwing
the cap back onto the receptacle, be certain that it is clean, so the insula-
t-ion will not be contaminated and so a low impedance bridging conductor will
not be formed between the high impedance contact and the grounded cap.
4-5. REFERENCE VOLTAGE BAITER?!. Battery Bl should be replaced at least
yearly. It is mounted on the PC board near the input receptacle; it is
easily seen when the bottom plate is removed. Replace with either a Mallory
RM-k0l.R or a Burgess Hg-I+OlR battery.
4-6. CALIBRATION MG n AMPLIFIER.
OF
a. Connect a volkmeter (recommended instrument is the Keithley Model 610A
Electrometer) to the 80 V MG N OUTPUT receptacle. Observe proper polarity.
Depress the PECOVER switch on the front panel and adJust the AMPLIFIER BAL-
ANCEcontrol until the voltage at the output is 0 volts (+O, -10 millivolts).
0563 4-1
MAINTENARCE MODEL
421 LOGn PERIODAMPLIFIER
There must be no positive output or the instrwnent will not calibrate properly.
b. Apply a lO-4 ampere current to the INPUT to obtain a full-scale deflection
on the log n meter. Adjust the IOG CAL potentiometer R135 (located inside the
Model 421 zimmediately behind the log n meter) for -80 volt output.
c, Adjust the SET 10-5 and the SET lo-11 controls as described in paragraph
2-4, a.
4-7. CALIBRATION PERIODCIRCUIT. If period calibration
OF is to be checked,
a test setup as described below is recommended.
a. To simulate the exponential change in reactor power level, a capacitor
discharge may be used to set up an electrical analog. The voltage discharge
mey be converted into a current by using a Himeg resistor to connect the cap-
acitor into the log n amplifier input as shown in Figure 3,
FIGURE3. Diagrem for Calib-
ration of Period Circuit
b. The period circuit, if correctly calibrated, should read directly the
time constant of the RC network (Rl and C) as C is allowed to discharge through
Rl when the key is opened With a loo-volt source end the key closed, the Log
n Amplifier will read lo- 8 ampere. When the key is opened, after an initial
transient, the period circuit should read RlC, In practice, C should be 1 to
10 microfarads and Rl varied to give various period readings. A time constant
or period of six seconds is a convenient calibration point. With the values
shown, the pe iod indicatio will be accurate from a current reading of
*bout 5 x 10-5 to about lo- 20 ampere and any period calibration should be
made while the current is in this range. Adjust the period meter with the
CffiIHRATE PERIODpotentiometer R221, located inside the Model 421 immediately
behdnd the period meter.
c. Note that since the instrument can only be calibrated on negative period
with this arrangement, the meter leads of the period meter should be reversed
for this calibration.
4-z 0563
MCDRL4211& n PRRIODAMPLIFIW RRPLACEABLEPARTS
SECTION 5. REPLACEABLE PARTS
5-1. lG3FLAcm PARTSLIST.
a. The Replaceable Parts List describes the components of the Model 421
Log n Period Amplifier. The List gives the circuit designation, the part de-
scription, a suggested manufacturer and the Keithley Pert Number. The name
and address of the manufacturers listed in the "Mfg. Code" col!mm is contained
in Table 3.
b. In some instances, it is necessary to substitute parts in the instrument
you receive. These substitutions do not impair the performance of the instru-
ment . Either the substitute part or the part specified in the Replaceable
Parts List may be used for replacement purposes.
5-2. Ig)wTooRDERPARTS.
a. For parts orders, include the instrument's model and serial numbers, the
Keithley Part Number, the circuit designation and a description of the part.
All structural parts end those parts coded for Keithley manufacture (80164)
must be ordered from Keithley Instruments, Inc. In ordering a part not listed
in the Replaceable Parts List, completely describe the part, its function and
its location.
b. If any part ordered has been replaced by a new or improved part, the new
part will be shipped.
c. Order parts through:
Sales Service Department
Keithley Instruments, Inc.
1.2415 Euclid Avenue
Cleveland 6, Ohio
Telephone 795-2666, Area code 216
amp ampere Ml1 No. Military e Number
micro (10'Y?)
CbVar Carbon Variable k Mylar
CerD Ceramic, Disc
camp Composition i-i OhU
DCb Deposited Carbon pa? PolystyreB
P pica (10' )
m Electrolytic, metal cased
I f
k kilo (103)
Tar
volt
Variable
watt
zw Wirewound
M or meg mega (106) or megohms WWVar Wirewound Variable
milli (10-3)
k Manufacturer
TABLE2 Abbreviations and Symbols.
0563 5-l
REPLACEAELEPARTS MD?% 421r.a nPERIODAM%IQW
MODEL 421 REPLACEAPAE PARIS LIs!r
(Refer to Schematic Diagram 16298D for circuit designations)
CAPACI!lmE!
Circuit Mfg. KeitbJ.ey
Desig. Value Rating me Code Part No.
Cl01 150 pf 500 " p0J.Y 71590 C138-150P
cl.02 *.0001 pf CerD oll21 c22-l.OQP
Cl03 50 vf 2: v IBE 83125 c17-5OM
Cl04 0.02 jlf 69OV CerD 72982 C22-.02M
cJ.05 .OcOl~ C-00v CarD OIL21 c22-loop
~106 0.001 &f 6ooV CerD i'2982 c22-.oolM
c201 1.0 pf w 00686 C37-LOM
c202 *.wo1 &e gf :: CerD Oll.21 c22-loop
c203 50 Pf 83125 C17-50M
C204 0.1 fl 400 v T 00656 c30-o.lM
c301 16 fl 600-J E&c 14655 c34-16&l
c302 3.6wf V EM! 14655 C34-16M
c303 20 crp g v C7-2OM
c304 20 wf 450 v z ;;E C'7-20M
c305 0.02 )Lf 600 v CerD 72982 c22-.02M
~306 0.02 jlf 63OV CerD 72982 c22-.02M
c307 0.1 & MY 00656 c30-o.ul
~308 20 vf g:: Eta 37942 ~7-20~
C401 500 crf 50 v Eta 14655 c57-500
c402 500 bf 50 v Eta2 14655 c57-500
c403 0.01 &f 600 v CerD oll21 c22-.olM
c404 500 I@ 25 v EM: l4655 ~58-500
DIODES
circuit m3. Keithley
Desig. rype Number Code Part No.
D201 Zener lN706 12954 DZ-1
D202 Zener lN706 12954 DZ-1
D301 Selenium pro65 81.483 ~~-18
~302 Selenium pro65 81483 ~~-18
D303 Selenim pro65 81483 ~~-18
D304. Selenium pro65 am33 ~~-18
D305 Silicon J-N3253 02735 RF-20
~306 Silicon m3253 02735 RF-20
*Component in Model 4102 Input Assembb
5-2
mDEL 421 ICC n PERIODAMPLIFIER REPLACEmLEPARTS
DIODES(Cont'd)
circuit Mfg. Keithley
Desig. Type Number Code Part No.
Dtil Zener lN706 12954 DZ-1
Silicon Wla2 12065 RF-14
2lz; Zener IN715 12954 DZ-22
MISCELLANEOUS
PARTS
Circuit Mfg. Keithley
Desig. Description Code Part No.
Bl Battery, 1.34 v Mercury (Mfg. No. RM4W-R) 37942 m-8
Fuse, 3 amp, 3Ac 75915 J?u-2
Fuse, 1.5 amp, 3 AG 75915 m-8
Fuse.holder -. - 75915 m-3
Receptacle, RR Series, INPUT, Mil No. UC-560/U 02660 cs-30
(Mpg. NO. 82-805)
(Mating plug is Keithley part CS-31)
52 Receptacle, Microphone, +225 Mfg. No. a C) 02660 cs-34
--- Plug, Microphone, Mate of J'2 t Mfg. No. 80 M) 02660 cs-35
33 Receptacle, Microphone, 50 MV LCG N OUTPJT 02660 cs-32
(Mfg. No. 80 FCZF)
(Mating plug is Keithley part CS-33)
54 Receptacle, Microphone, 75 V LCG N OUTPUT 02660 cs-32
(Mfg. No. 80 PC2F)
(Mating plug is Keithley part CS-33)
55 Receptacle, Microphone, 50 MV PERIODOUTPUT 02660 cs-32
(Mfg. No. 80 FC2F)
(Mating plug is Keithley part CS-33)
~6 Receptacle, Microphone, 10 V PERIODOUTPUT 02660 cs-32
(Mfg. No. 80.PC2F)
(Mating plug is Keithley part CS-33)
Ml Meter, Log n 80164 m-28
M2 Meter, Period 80164 m-4
--- Pilot Light Assembly 80164 m-g
..-- Bulb, Miniature bayonet base, (Mfg. No. 51) 08804 a-8
Pl plug, RR Series (Mfg. NO. 82-816) 02660 cs-31
P2 Line Cord 80164 co-2
--- Cable Clamp 80164 cc-7
P3 to P6 Plug, Microphone (Mfg. No. 80 MC2M) 02660 cs-33
Sl Rotary Switch less components, OPERA!PE 80164 SW-38
--- Switch Assembly with components, Operate 8a64 163018
m-e Skirted Knob Assembly, Operate Switch 80164 15459A
s2 Push Button Switch Assembly, RECOVER 80164 14130B
1066R 5-3
MISCELLANEOUS
PARTS(Cont'd)
circuit Description Mfg. Keithley
D&ii@:. Code Part No.
Toggle Switch, SPIY.C,
OPERATE CHf%K00
- 04009 SW-5
Et Tog&e Switch, SPST, ON-OFF 04009 SW-4
Tl Transformer 80164. TR-60
RFsISloRS
c 1rcuit m3. Keithley
Desig. Value Rating Type Code Part No.
RlOl 34 MJ Rl2-34K
R102
R103 ??lm n
lo
E22:
63060 gt:EP
R104 75 kR 01661 RI&75K
R105 27.3 161 01661 ~12-27.3~
R106 2OOs-l wwvar 71450 ~~3-200
Xl07 500 n DCb 00327 Rl2-500
R108 300 kQ DCb 00327 RI%3OOK
RlO9 3m WWVar 71450 m3-3K
RLLO 10 Its-l corn OU.21 Rl-1OK
RSIJ. 50 u-l wwvex 73138 RP4-50K
Rl32 50 xl Xb 00327 RX?.-5UK
R=3 *22 m Camp 44655 Rl-22M
RLl.4 *10 m Deb 00327 RlZ-10M
Ru5 *lo m DClb 00327 RlZ-lOM
RlJ6 200 i-4 WWVar 02lLL ~~23-200
R-U.7 150 D ww special R65-150
RlJ.8 250 s-l WW Specidl zk% R65-250
RlLg 22.5 m ww 63743 ~5-22.5K
Rl20 6~2 IXb 01661 Rl.3-6M
RI.21 22.5 b-2 ww ~5-22.5s~
Rl22 220 la IYzb Rl2-220K
~123 470 -x-z Deb ~12"47OK
RI.24 1.14 MCI .Txb RI&l.lti
RI.25 l.oMl DCb RX?-10K
R126 camp OU.21 Rl-LOK
X127 DCb 00327 R12-600K
RL28 Lx3 00327 RI&6QK
Rl29 Eb 01661 RI&l&
R130 camp M55 R2-XCOK
Woqponent in Model 4102 Input Assembly
5-4 1066R
WDFZ 421LoG n PERIODAMPLIFIEB REPLACEABLEPARIS
RESISMRS (Cont'd)
Circuit WT. Keithley
De&g. Value Rating Type code Part No.
R131 1.5 MQ IX!b 01661 RITZ-1.5M
~I.32 22.5 ks-2 ww 63743 ~5-22.5~
R133 50 kQ IYJb Ejl2-50K
R134 250 ks2 SCb k%: RX&250K
Rl35 500 kQ. CbVar 71450 RP7-500K
~136 50 fi Eb 01661 RITZ-50
ru37 4mm Deb RIdlOOK
~138 75 m Eb 32: Ru-75K
R201 600 la Eb 00327 Rl2-600K
R202 47 M? cow Rl-47K
~203 *22 ml camp E;ii RL-22M
~204 *lo I"m Eb 00327 R12-lOM
~205 *lo MQ Eb 00327 R12-10M
~206 200 a war 71450 ~~3-200
~207 150 a WW Special 80164 R65-150
~208 250 n WW Special @x64 x65-250
R209 22.5 x-2 ww 63743 ~5-22.5~
R210 ~MQ EC 01661 R13-6M
R2ll. 5.25 MQ Eb 00327 ~13-5.25~
X212 22.5 m ml 63743 ~5-22.5~ _
~213 l.oola Eb 01661 Rl2-MOK
~214 100 162 Eb 01661 Rl&lOOK
R215 1m DCb 00327 Rl2-lM
~216 3.4 M-l DCb 00327 R12-3.4K
R217 allal Eb RlZ-@K
~218 1.5 im rxb 32 RL2-1.5M
R219 22.5 Idl wd 63743 R5-22.5K
R220 1162 Wb 00327 X12-lK
X221 3 161 WWVar 71450 RP3-3K
R222 6Kl Eb 01661 Rl2-6K
~223 LXb 01661 R12-LOK
R224 gl? Xb 01661 ~12-50
X225 55 PJ? Eb 01661 Ra-55K
R301 loon ww 44655 X4-100
~302 loos-l cow? Oll21 Rl-100
R303 3*3 MQ cow 44655 Rl-3.3M
R304 1250 s-2 ww 44655 R5-I.250
R305 1250 s2 ww 63743 R4-I.250
Womonent in Model 4102 Inuut Assemblv
1066R 5-5
REsIS~FfS (Cont ' d)
circuit Mpg. Keitliley
Dssig. Value Rating code Part No.
x306 I.250 s1 R4-1250
5m R4-5K
~~~ Rl-lM
R309 28% ~2-68~
R3J.o 2.2 xl 00327 R.l.2"2.2M
R3= 2.2 m 00327 RI&2.2M
~312 1Msl 00327 lCL2"lM
R313 01661 RJ.2"1.3M
R314 00327 Rl2"&OK
R4Ol R6"5
R402 yG;: Rl-560
R403 lam Oll.21 Rl-lOK
R404 lokn OU.21 RI.-loK
R405 150 kSl OlJ.21 RL15OK
R406 6&a 44655 Rl-680
R407 lokn OlJ.21 Rl-.l.OK
R408 4.7 kn oll21 Rl-4.7K
*500n 0327 Rl2-500
i%: ++qoo n a327 ~12-500
R4Xl 47 s-l NJ%, 5 w ww 91637 R4A-47
TRAWISTXS
circuit Mfg. Keithley
Desig. Number code l%xt NO.
mm3 02735 XKil
:; 2~1381 01295
3 2~1381. 01295 s::
2~1381 ol.295
45 2~1.381 01295 iis
46 2Nl-535 802ll m-7
VACWM~
Circuit WT. Keitbley
Desig . Nuder Code Part No.
Vl ME2
v2 ~5886 E%i
'~5886 em64
2 94154
v5 %2 94154
Component in Model 4102 Input Assembly.
WNominal value, factory selected.
5-6 1066R
MODEL
421Ice n PERIODAMPLIFIER RFPLAcEABLEPAFiT;
VACUUM
!WEE3 (Cont ' d)
circuit Mfg. Keithley
Desilx. Number Code Part No.
v6 86684 EV-l2.m
v7 iz? 8535% EV-6~6
v8 *5806 Epg;;
v9 *5886 &U3+ " "
VlO m7 73445 Ev"l2Au7
VI-J- 86684 EIv"6c4
VIZ z4 0COl.l PI-61~4
v13 6y6Gn OQOll Eiv-6YcGA
v14 7025 73445 N-7025
VI.5 OA2 85599 EV-OA2
~16 w3 Ev"cG3
VI7 7025 EV-7025
Component ti I&de1 4102 Input Assembly
1066K 5-7
REPLACEABLEPARTS MODEL421 LOG n PERIOD AMPLIFIER
0011 Sylvania Electric Products, Inc. 44655 Ohmite Mfg. Co.
Electronic Tubes Div. Skokie, 111.
Buffalo, N. Y.
56289 Sprague Electric Co.
0327 Welwyn International, Inc. North Adams, Mass.
Cleveland, Ohio
63060 Victoreen Instrument Co.
0656 Aerovox Corp. Cleveland, Ohio
New Bedford, Mass.
63743 Ward Leonard Electric Co.
0686 Film Capacitors, Inc. Mount Vernon, N. Y.
New York, N. Y.
71450 CTS Corp.
1121 Allen-Bradley Corp. Elkhart, Ind.
Milwaukee, Wis.
72982 Erie Resistor Corp.
1295 Texas Instruments, Inc. Erie, Pa.
Semi-Conductor Products Div.
Dallas, Texas 73138 Helipot Division
Beckman Instruments, Inc.
1661 Wilrite Products, Inc. Fullerton, Calif.
Cleveland, Ohio
73445 Amperex Electronic Corp.
2111 Spectral Electronics Corp. Hicksville, N. Y.
San Gabriel, Calif.
75915 Littelfuse, Inc.
2660 Amphenol Connector Division Des Plaines, 111.
Amphenol-Borg Electronics Corp.
Chicago, Illinois 80164 Keithley Instruments, Inc.
Cleveland, Ohio
2735 Radio Corp. of America
RCA Semiconductor & Materials Div. 80211 Motorola, Inc.
Somerville, N. J. Chicago, Illinois
4009 Arrow-Hart & Hageman Electric Co. 81483 International Rectifier Corp.
Hartford, Corm. El Segundo, Calif.
8804 General Electric Co. 83125 General Instrument Corp.
Lamp Division Capacitor Division
Cleveland, Ohio Newark, N. J.
2065 Transitron Electronic Corp. 85599 General Electric Co.
Wakefield, Mass. Schenectady, New York
2954 Dickson Electronics Corp. 86684 Radio Corp. of America
Scottsdale, Ariz. RCA Electron Tube Div.
Harrison, N. J.
4655 Cornell-Dubilier Electronics
Div. Federal Pacific Electric Co. 91637 Dale Electronics, Inc.
Newark, N. J. Columbus, Nebr.
,7942 Mallory, P. R., and Co., Inc. 99942 Hoffman Electronics Corp.
Indianapolis, Ind. Semiconductor Division
El Monte, Calif.
TABLE 3. Code List of Suggested Manufacturers.
5-8 1066R
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