HP 5061A Service manual

MANUAL CHANGES
April 21, 1980
CHANGE DATE:
MANUAL DESCRIPTION
INSTRUMENT:
SERIAL PREFIX:
1,2,3,4, 5,6, ,8
1816A 1908 A
1
A5 Series 1916
1840A
1.2
A5 Series 1840
1936 A
3
1 thru 11
1940 A
A2 Series 1848 4
1 thru 12
1948A
1852A
1 thru 13
2002A
1904 A
A5 Series 1904
3.
5061A-1
5061 A-2
5061 A-3
5061 A-4
5061 A-6
5061 A-
5061 A-8
NOTE — THE FOLLOWING ERRATA APPLIES ONLY TO INSTRUMENTS WITH SERIAL PREFIX NUMBER 1740A.
1 R/S/T/U — 859- 860- 865/ 883/88 8/88 / 894/ 893/889 -8901/8942/8926-9825/9652/9669/E/
DATE PRINTED:
HP PART NO:
MICROFICHE NO:
IF YOUR INSTRUMENT
HAS SERIAL PREFIX
OR SERIAL NUMBER
JUN 19 8
05061-9052
05061-9053
MAKE THE
FOLLOWING CHANGES
TO YOUR MANUAL
(This change supersedes all earlier dated
changes)
• Make all changes listed as ERRATA.
© Check the following table for your
instrument ’ s serial prefix or serial number
and make listed change(s) to manual.
MAKE THE
FOLLOWING CHANGES
TO YOUR MANUAL
HEWLETT
PACKARD
5061A Cesium Beam Frequency
Standard Operating and Service Manual
1 40 A
□ NEW OR REVISED ITEM
The following Service Notes are available from your local HP Sales and Service Office.
Service Note No.
1.2,3, 4,5
1.2,3,4,5,6
Description
Improve Decade Divider IC4 in Synthesizer A1
Preferred Replacement Parts that Increase Reliability
Cesium Oven Controller Circuit Modification
Increasing Reliability and Tunability of Harmonic Generator Assembly (A4)
Installation of Hot Wire Ionizer Current Limit Resistors
Summary of Important Circuit Changes, Procedures and Replacement Parts
Modification for Improved Short Term Stability
3, thru
1 thru 10
IF YOUR INSTRUMENT
HAS SERIAL PREFIX
OR SERIAL NUMBER
ERRATA
Page 8-5, Figure 8-5, Wiring Diagram:
Add “ (Serial Prefix 1816Ai ” to caption.
Page 8-35, Figure 8-20, A9 Schematic Diagram:
Change SERIES numbers for A9 and A9A1 to 1816.
Page 8-55, Figure 8-30, A1 Schematic Diagram:
Add “ (SERIES 1 401 ” to A1 description on bottom edge of diagram.
Page 8-5, Figure 8-5, Wiring Diagram:
Replace with attached Figure 1 Signal Wiring Diagram (Serial Prefix 1 40A).
Page 8-35, Figure 8-20, A9 Schematic Diagram:
Replace with attached Figure 2. A9 (05061-6134 SERIES 1 40) Schematic Diagram.
Page 8-55, Figure 8-30, A1 Schematic Diagram:
Change output from terminal 4 to “ TO S2B (4, 6, 11,12) MODE ” .
Changeout put from terminal 22 to “ TO SB2 (2, 3) MODE ” .

MANUAL CHANGES MODEL 5061A Page 2
ERRATA (Continu d)
the battery will charge for 13 to
are transposed.
on during the charge cycle.'
Page 6-28, Table 6-1, Replaceable Parts:
Change HP and Mfr Part Number for KIT:RACK MOUNT from 5060-0 to 5060-8 42.
Page 6-18, Table 6-1, A11 Replaceable Parts:
Change A11A1R33 and R34 to 0811-3288; R: FXD WW 0.025(1 10% 2W; 28480; 0811-3288.
Page 8-45, Figure 8-25, A11 (05061-6009) Schematic Diagram:
Change values of A11A1R33 and R34 to 0.025 ohms.
Title Page (inside front cover):
Change paragraph under “ SERIAL PREFIX: 1 40A ” to the following:
This manual applies directly to HP Model 5061A Cesium Beam Frequency Standards having Serial Prefix 1 40A.
Page 3- , NOTE following paragraph 3-14. c:
Change second sentence to: "Thus, when the instrument is initially turned on,
18 hours and the BATTERY light will be on during the charge cycle. ”
Page 5-40, Paragraph 5-234, fifth line:
Change "A15R30 and A15R31 ” to A15R33 and A15R34.
Page 5-40, Paragraph 5-236, second and third lines:
Change "P+50V)" to "(=50V) ” .
Change "A15R30 and A15R31 ” to A15R33 and A15R34.
Page 5-40, Paragraph 5-239:
Change to the following:
If assembly A19 is replaced, resistors A15R33 and A15R34 on Power Regulator Assembly A15 must be changed.
Refer to paragraph "5-186. ELECTRON MULTIPLIER VOLTAGE ADJUST (A15R33, A15R34). ” for procedure.
Page 5-41, Paragraph 2-254, second line:
Change sixth word to “ operating ” .
Page 5-43, Paragraph 5-260, step c:
Change “ 18 to 21 ” to "13 to 18 ” .
Page 5-43, Paragraph 5-260, step d:
Change "bread ” to "lead ” .
Page 5-43, Paragraph 5-262:
Complete second sentence to read as follows: “ To isolate the the trouble circuit, perform following checks
in order given: 1) Timing Oscillator (Paragraph 5-268), 2) Decades (Paragraph 5-2 1), 3) Reset Preset (Para 
graph 5-26 ) and 4) Logic Comparator (Paragraph 5-269). ”
Page 6-33, Table 6-3, Option 001 Miscellaneous Replaceable Parts:
Change 05061-6061 to W26; 05061-6104; CABLE ASSY: FREQUENCY DIVIDER; 28480; 05061-6104.
Add in "Reference Designation ” column.
W2 for 05061-6062 cable assembly.
W31 for 05061-6068 cable assembly.
W32 for 05061-6069 cable assembly.
Page 8-11, Figure 8-9, Al Schematic Diagram:
Reference designators for C31, C32; CR36, CR3 ; and R 2, R 3 ;
Change C31 to C32 and C32 to C31.
Change CR36 to CR3 and CR3 to CR36.
Change R 2 to R 3 and R 3 to R 2.
Delete A1C39 capacitor (2500 pF) in the drain circuit of FET Q3.
Page 8-53, Figure 8-29, A16A1 Schematic Diagram:
Add "CR4 ” label to diode between U2 and CIO in A16A1 component locator illustration.
Change A16A1 schematic diagram by transposing A16R14 and A14C12. Capacitor C12 connects between
U2(9) and one end of R14. The other end of R14 goes to circuit board common.
Remove connection between A16A1Q3 collector and A16A1U2 pins 11 and 14. Add connection between cir 
cuit board common and A16A1U2 pins 11 and 14.
Page 6-33, Table 6-3, Option 001 Replaceable Parts:
Add A5; 05061-6118; MODULE ASSY: DIGITAL DIVIDER.
Page 6-30, Table 6-2, Option 002 Replaceable Parts:
Change "Description ” for BT1 to BATTERY 24V 2.2A-HR NI-CD WITH FLEX LEADS; 28480; 1420-0053.
Page 8-19, Figure 8-13, A5 BLOCK DIAGRAM:
Change A5 DIGITAL DIVIDER ASSY part number (top of diagram) from 05061-6011 to 05061-6118.
Change A5A1 POWER SUPPLY part number from 05061-6015 to 05061-6114.

MANUAL CHANGES MODEL 5061A Page 3
J 16
JIT
BRN
HEATER
ELECTRON MULTIPLIER
55M
BRN-ORN
HEATER
TO AI5(5)
COMMON
WHT-ORN
HOT WIRE IONIZER
J2 J6
£
LF coil
5
ORN-WHT
HOT WIRE IONIZER
5
W7
J3
15
C FIELD
SIGNAL
T
4
JI
14
THERMISTOR
J5 J4
COMMON
T< >T
9
WHT-RED
IO
W2I
J2
2SYNTH2
J3
W8
I3 HZ
WHT-BRN-YEL
B
3 22
21
BLU
TO AI ( 13)
J3
J2
MULT
JI
RED
JI
R
J3
SWEEP OUTPUT
J2
I37HZ
BRN q WHT-RED
19
J4
J2
WHT-RED
W4
+I8.7V(A> W-R
20
ON
o-
J5
=
WHT-YEL-GRY
OFF J6
6
AI7(34)
>
TP I
WHT-ORN-GRY
GRN
A 1 7(33)
GRN
>
WHT
W5
WHT-RED-BLU
o
7-1
V
-EFC
WHT-BRN
■o
TO AI7 17)
--0
| COARSE |
O
O
WHT-BRN-YEL
8
>
RED -O TP2
C,OFF O
WHT-RED
JI
+ I6V
J2(3) J2(6)
| LOOP OPEN~~|
A>-1
3
o 3
-I6V
J2(8)
J2(9)
■Q
OPER
WHT-RED
' ol
olJ
42(5)
LTC
5.
J2(4)
_8
O
BLK
WHT-BRN-YEL
AI (3)
J
T
■O AITTP I'CONTROL'
WHT-RED-BLU
■O
WHT-BRN-GRY
,1 I
2
12
Figure 1. Signa Wiring Diagram (Seria Prefix 1740A)
k
MOD
S5
TO SIA(9)
(METER)
AI2PI7
*2 H-
O ’ 4
£Ft
WHT-
RED
+25V TO +33V
FROM AI7(40)
+25V TO +33V
FROM AIT(4I)
AI2PI6
BRN
OSC
OVEN
I
I
AI2
CESIUM
BEAM
TUBE
+25V TO +33V
TO AI7(47)
+I8.7V(A)
TO AI7(39)
+I8.7V(D)
TO AI7 49)
*
R2
I7.8K
ZEEMAN
MOD INPUT
R4
I OK
TEST
SIGNALS
FROM Al I JI (22)
CESIUM OVEN
CONTROLLER
FROM
Al IJI(2O)
FROM
Al I JI (23)
+I8.7V(A)
FROM AI7(48)
AI7R9
200K
AI7RI
IK
R5
IOOK
A8
PHASE DETECTOR
A9
OPERATIONAL
AMPLIFIER
R6
I2M
TO
SIA(8)
TO Ml THRU
SIB(8)
BEAM I
METER ADJ
AI4
LOGIC
CIRCUIT
+I8.7V(B)
FROM A1 7(37>
+I8.7V(A)
FROM AI7(50)
+ I 8.7V( A )
FROM AI7(49)
+I8.7V(B)
FROM AI7(37)
FROM
Al IJI(I5,I6)
FROM
AI I J I ( IT,IB)
FROM
AI7(21 )
FROM
AI7(29)
FROM
Al IJI(I3)
WHT-
GRY
5MHZ
TO AI3J2
BUFFER AMPL
FROM AI9(4)
-2500VDC
POWER SUPPLY
4* P3
+I8.7V
FROM A 17(43)
A3
MULTIPLIER
AIO
OSCILLATOR
A4
HARMONIC
GENERATOR
JI
R3 1
20K f
+18. 7V
TO AI7(37)
W-R
JI
L2
4MH
A7
AC AMPLIFIER
ALARM
I 1 —
!
§
!
C2
8UF
20,21
BLK
FROM A' (38)
+I8. V(D)
<>L I
I
_90MHZ
W23
T
, WI4
>T-e-
' 1 BLK
•T
W3
WIO
W9
W22
T
wht - red q blk
AI7(54)
A 17(22)
W30
WIT
t
WHT-ORN
A 17(3 I )
(GREEN)
W28
T
TP3
TP4
T
-IOV
FROM AlIJI(6)
| PHASE DETECTOR
OUT
WHT-VIO
A 17(32)
(AM8ER)
A 17(5)
- M
+20V
RED
W29
WHT-
I ORN
+ I5V
WHT-
BRN-
_ GRN
WBG
WHT-
BRN-
_ BLU
WBB
A 17(4)
□3
| LOGIC RESET |
BLK
J7
P3
IV
+24V
5MHZ
FROM AI3JI
BUFFER AMPL
“ TT
I 15VAC
TWISTED PAIR ■
TO A6J6
FREQUENCY DIVIDER
TO AI5(6)
E.M.REGULATOR RETURN
Al
SYNTHESIZER
+18. 7V
FROM AI7145)
+18. 7V
FROM A 17(44)
+I8.7V(D)
FROM AI7(53)
a X o
1 o
I _
S2B
WHITE DOT
ON COAX
.rJRT
CW2 250K
| WHT-
GRN
SYNTH
TEST POINT
AIT(TPT)
W-R
WHT- I
RED | WI5
+I8.7VID)
FROM AI7(38)
11
P2
+EFC
g274HZ
I I ----
1.2 >4 ----
k Al
k 5
J2
-Q- C control Z
CONTROL VOLTAGE
TEST SIGNALS
AC '
J 15
J3
3,8
|GRY.
' YEL
ii S2C
-Lp — r*o
s
DIV
P4 I E
W6
_>X L d £GAUSS2 DEGAUSSING COIL
I TO JIS OPT 004 ONLY
„
F PINS G.H
1 FROM A1 8(5)
1 +3500VDC
1 POWER SUPPLY
; p
I MODE |
S2 Q
l S2A
-V-L
T< 1.2 <-r
c , I BRN-WT
T< 6.2 < T ------
' BLR
Y -H S2B
■k) ■ ; K )
TO AIT( I I)
I 2ND I
| HARMONIC |
rxicr T1i ~| 0)
*
Rl
7500
z 2ND
HARMONIC ERROR
SIGNAL SIGNAL
| -- *• JI8(K)
| WHT-RED-YEL
WHT-YEL-VIO
i ► JI8(J) ”
"P 1000
I CONTINUOUS I
| OPERATION I

MANUAL CHANGES MODEL 5061A Page 5
| CS OFF I
O
TP5
TP4
WHT
-e-
o
LTC
O
!
o
/77
I
L
L___
--- 1
TP3
A9AI
(WHT/RED/YEL)
+ I5V
TP I
(WHT/YEL/VIO)
-I5V
NC
+300V
II
AI7(3)
-300V
BLK
CHASSIS
O
+ I5V
GRN
(WHT/BLU~)
OUT
>-©■
CRI
CR2
(WHT/BLK)
rh
BLU
L
+ I5V
7
Lr
2
U2
OUT
3
-I5V
P2
DC
SIGNAL FROM
PHASE DETECTOR
A8J6
R6 *
I2M
R5
I00K
+ I6V
Al I 8>
-I6V
Al I (7)
TO
J I8(J)
P/0
P2
OPERATIONAL AMPL IFIER CIRCUIT BO ARD ASSEMBLY (0S06I -6 1 35) ( SERIES I74O)
Rl
75
R2
75A.
TEFLON STAND-OFF
INSULATOR
R3
IK
,CR3
I5V
R5
200K
R4
200K
R6
200K
C3
30PF
AI7TPI
•CONTROL*
AI7R9
200K
A I TRI
1 000
CONTROL VOLTAGE
TO AI4(2)
TO SIA(9)
METER
C ontrol :
ci _L
I.OUF 'T'
_ _ C2
■p IUF
FROM
CESIUM OVEN
CONTROLLER
Al I
C2
SUF
CT
C5
5UF
Hf-
P/O
S2B
I oS-
I
P/0
J2|
DC CONTROL VOLTAGE TO
5MHZ OSCILLATOR
AIO (PI)
■-EFC*
TP2
TO
JI8(K)
.1
■k p
k.k
i . i . i ;
T< 2 < t - NC
I
| P/0
1 J2
T< 5 ^T —
O P/0
______ J
A 1 (5)
! | LOOP OPEN~|
I | OPER
1
P/0
S2C
CT
i
° i
— s-
R4
I OK
C4
.04
HH
A9 OPERATIONAL Ak£LIFIER_ASSEMBLY_( 0506 1 J, 134HSERIES_1 40)
A 1 (22)
•K
| -I5V
P/0
1 1 i

MANUAL CHANCES MODEL 5061A Page
Change A1 R2* to 0 5 -0962;
Change A1 R3* to 0 5 -0959;
Change A1 R4* to 0 5 -09 2;
Change A1 R * to 0698-345 ;
Page 8-55, Figure 8-30, A1 Schematic Diagram:
Change R2* to 39K.
Change R3* to 30K.
Change R4* and R9* to 100K.
Change R * to 316K.
Page 5-10, Table 5-3, Assembly Designations:
Change A16 part number 05061-60125 to 05061-6125 and part number 05061-60136 to 05061-6136.
Page 5-2 , Paragraph 159, Cesium Tube 05061-60 Specifications:
Change Peak beam current to equal 0.8 X 10-8A.
Page 5-29, Paragraph 5- 0:
Delete first three sentences (approximately 8 2/3 lines).
Page 5-30, Paragraph 5-1 1b, third line:
Add "de ” between "impedance" and "voltmeter ” .
Page 5-30, Paragraph 5-1 1k:
Change power of 10 in formula from "1013 ” to "10-13 ” .
Page 6-1 , Table 6-1, All Replaceable Parts:
Change A11Q5 and Q6 from 1854-0613 to 05061-8013 in HP Part Number column.
Page 6-30 thru 6-32, Table 6-2, Option 002 Replaceable Parts:
Add "(SERIES 1 36) ” to Description for A2.
Add an asterisk (*) beside A2R2 and A2R64 reference designations.
Change “ Mfr Part Number ” for A2C to 150D10 X903052.
Page 8-13, Figure 8-10, A2 Schematic Diagram:
Change A2 series number, at top of diagram to 1 36.
Add an asterisk (*) beside A2R2 and A2R64 reference designators.
Page -1, Table -1, Manua Backdating:
Change second entry in left-hand column to the following:
"1 24A (-0138 and below except -013 8, -013 9, or -01384) with series 1 36 circuit board for A2
in Option 002 or 003. ”
Page -2, CHANCE 2:
Change CHANGE 2 to the following:
Page 6-30, Table 6-2, Option 002 Replaceable Parts:
Change A2 series number from 1 36 to 1512A.
Change A2CR5 from 1902-0041 to 1902-05 9.
Page 8-13, Figure 8-10:
Change Series No. (at top of diagram) from 1 36 to 1512A.
Delete asterisk (*) beside R2 and R64.
Page 2-2, Paragraph 2-14, Second sentence:
Change sentence to read "Parts necessary to convert the instrument for rack mounting are available
as a kit.
Page 8-55, Figure 8-30, A1 Wiring Diagram:
Change A1 terminal 3 connection to MODE switch "from S2B( ,8) ” to "from S2A( ,8) ” .
Page 1-3, Table 1-1, Specifications:
Change POWER: to 115V ±10%, 48-440 Hz; 230V ±10%, 48-66 Hz; or 22 to 30V de.
Page 8-11, Figure 8-9, Al Schematic Diagram:
Change Al part number from 05061-608 to 05061-609 and A1A1 from 05061-6088 to 05061-6098.
Page 5-13, Figure 5-6, Synthesizer Operational Check Setup:
Change model number of HP counter to 5345A.
ERRATA (Continu d)
Page 8-21, Figure 8-14, Part of A5 Schematic Diagram;
Page 8-23, Figure 8-15, Part of A5 Schematic Diagram; and
Page 8-25, Figure 8-16, Part of A5 Schematic Diagram:
Change A5 part number shown on top of diagrams from 05061-6011 to 05061-6118.
Page 6-23, Table 6-1, A1 (05061-6018) Replaceable Parts:
~ R: FXD ELM 39K 2% .125W; 28480; 0 5 -0962.
R: FXD FLM 30K 2% .125W; 28480; 0 5 -0959.
R: FXD FLM 100K 2% .125W; 28480; 0 5 -09 2.
R: FXD FLM 316K 1% .125W; 28480; 0698-345 .

■0
MANUAL CHANCES MODEL 5061A Page 8
j.
k.
I.
m.
n.
o.
P-
q-
8
9
10
12
13
14
beam current indi-
until current is halfway
— " " r making the
that the peak indication is obtained when the
' " t one encountered as
and then cw to t.._
to a peak of lower
peak indication on t>>«. «
was adjusted to ±0.1 Hz of 5 MHz, do the
ERRATA (Continued)
ss *. ...» .....
h.
i.
line between A13J2 and A3J3.
line between A13J1 and A1J1.
line between A1J3 and JT5 SYNTH.
line between A11J1 (15-18) and A12.
OVEN POWER line between A11 and A12.
Push A4 attenuator halfway in and lock in place.
Adjust A4R1 completely ccw, then carefully cw for a peak indicatio noni the de volt 'JJ^a^between the
halfway between peak and background.
Adjust A4 cavity tuning control (see Figure 5- ) for a peak indication on the de voltmeter. Tighten the
cavity Tuning Control Lock. If in step d., the oscillator frequency
first part of step d.
Keen locknut snug and adjust A4S5 for a peak indication on the de voltmeter. Be sure
cation never exceeds 5% of the peak value noted in step i. If it does, adjust A4R1 ccwu...
between peak and background.
Repeat steps 11 and 12 until no further beam current increase is attained by adjusting A4S5. When
final adjustment, tighten the locknut while adjusting A4S5, so t
locknut is tight (do not overtighten).
Loosen attenuator and push full in (maximum attenuation).
Adjust A4R1 full ccw, and then cw to the first peak indication on
Pull A4 attenuator out until de voltmeter peaks then decreases slightly.
and 15 on line from A12J1 1P1 ) and A J1.
on DC ERROR line at A8J6.
and 11 at A8J1 TEST.
at A J2 2N HARMONIC TEST.
at A8J4 13 Hz.
on line between S3 ON and A8J5.
location number for waveforms at the following points:
at A10J3.
at A10J4 (DIV).
on
on
on
on
on
Delete reference to “ Synthesizer time scale 0366. “ under waveform number 5.
the de voltmeter.
about 1 minor division of the voltmeter
qhisTthe ’ ’ opdmum beam current). Carefully lock attenuator set-screw.
CAUTION
In Step o, the beam current may decrease as the attenuator is pulled out.
Should this occur, lock the attenuator all the way in, and adjust A4R1.
Turn A4R1 maximum ccw, then cw until the de voltmeter indicates a peak (see figure 5-10a).
Continue turning A4R1 cw. The de voltmeter indication will remain the same, or decrease, then increase again
to the peak level of step o. This double peaking indicates saturation.
NOTE
If the "saturated ” double peak is not evident in steps p and q, pull A4
attenuator out slightly and repeat steps p and q (see Figure 5-10a). If saturation
cannot be attained with the attenuator pulled out all the way, realign A4
Harmonic Generator as described previously.
If A4R1 is turned further cw, the de voltmeter indication will decrease, then increase
amplitude than in step o.
Tkt rnrrprt neak is the first one encountered as R1 is turned cwfrom its maximum ccw position. Reset A4R1 by
burning R full ccw and then cw to the first peak. This completes Harmonic Generator A4 alignment.
Page 8-63, Beam l:Low, Troubleshooting:
rhanpp Stens "35/45 ” to read as follows:
"Remote P MP2 Check voltage at A4P2; should be >0.2V rms.
Pa ®dd"test' ,8Ure ‘ '"waveforms at the following points:
1
2
3
4
5
6
7

MANUAL CHANGES MODEL 5061A Page 8A
□
Change component locator to show an alternate location for C16. This capacitor appears at the lower end of IC between
R59 and CR32. The alternate position is between CR29 and R36.
□ Page 8-15, Figure 8-11, A3 Component Locator:
Add R38 callout for resistor located between C28 and Q5.
Add R39 callout for resistor located between C42 and L13.
Page 8-23, Figure 8-15, A5A2 Component Locator:
Change resistor designated R43 (midway between IC4 and IC5) to R42.
Change resistor designated R42 (adjacent to IC10) to R43.
□ Page 8-2 , Figure 8-1 , A6 Component Locator:
Change "C14 ” located between CR4 and R16, near T2, to C13.
Change "R4 " located between C36 and R39, near Q11, to R41.
□ Page 8-49, Figure 8-2 , A14 Component Locator:
Change "R36" located between CR6 and R33, near Q10, to R38.
□ Page 8-51, Figure 8-28, A15 Schematic Diagram:
ERRATA (Cont ’ d)
Page 8-9, Figure 8- , A1 Component Locator:
Transpose the reference designators for R59 and R60. R60 is adjacent to C24 and R59 is adjacent to CR31.
Page 8-5 , Figure 8-31, A15 and A18 Circuit Diagrams:
Change A15Q15 to 1854-0062.
Change A15R23 from 3300 to 33K ohms.
Change A18Q2 to 1854-0062.
Page 6-33, Table 6-3, Option 001 Replaceable MISCELLANEOUS Parts:
Change 05061-6034 to 05061-6100 in "HP" and "Mfr Part Number" columns.
Page 8-53, Figure 8-29, A16A1 Component Locator:
Add C5 over unidentified capacitor between upper end of U1 and C8.
Add C6 over unidentified capacitor between lower end of U1 and C8.
□ Page 3-4, Figure 3-3, Rear-Panel Controls:
Change "SYNC" in item "6." to SYNTH.
□ Page 5-10, Paragraph 5- :
Add attached page 5-10a Performance Check Test Card.
□ Page 6-6, Table 6-1, A3A1 Replaceable Parts:
Change HP Part Number for A3A1C33 and C36 to 0160-2225.
□ Page 8-4, Figure 8-3, Front-Panel View:
Change switch marked "S3" in front-panel view to S5.
□ Page 8-13, Figure 8-10, A2 Component Locator:
Change R28 to 10K and R32 to 4 00 ohms.
□ Page 8-53, Figure 8-29, A16 Schematic Diagram:
Add "10" by U2 pin labeled "SHUT" in A16A1 diagram.
Add a connection between Q1 through Q emitters in U2 and U2 pin 15 shown in A16A2 diagram.

MANUAL CHANGES MODEL 5061A Page 9
CHANGE 1 (1816A)
Page 6-13, Table 6-1, A9 Replaceable Parts:
Add "(SERIES 1816)" to Description of Module A9 and circuit board assembly A9A1.
NOTE: The Wiring Diagram (Page 8-5, Figure 8-5), A9 Schematic Diagram (Page 8-5, Figure 8-20), and A1 Sche 
matic Diagram (Page 8-55, Figure 8-30) apply to instruments with Serial Prefix Number 1816A or higher.
Page 6-24, Table 6-1, CHASSIS & MISCELLANEOUS Replaceable Parts:
Change F1, F2, and F3 fuseholders (1400-0084) to the following:
2110-0564; FUSEHOLDER BODY; 28480; 2110-0564.
2110-0565; FUSEHOLDER CAP; 28480; 2110-0565.
2110-0569; FUSEHOLDER MTG NUT-PLASTIC, HEX: 28480; 2110-0569.
CHANGE 2 (1840A) (STANDARD INSTRUMENT)
See NOTE at end of CHANGE 10.
Page 6-23, Table 6-1, A19 Power Supply:
Add (SERIES 1840) to "Description ” for A19 (05060-6092).
Page 8-5 , Figure 8-31, A19 (05060-6092) Schematic Diagram:
Change series number at top of A19 schematic from "1240A ” to 1840.
Change minimum output voltage range at A19 pin 4 from "-1800V" to "-1250V".
Instrument serial prefix number changes from 1816A to 1840A with this change for A19.
CHANGES (A5 SERIES 1840) (OPTIONS 001 or 003)
NOTE: The following change for A5 series number does not affect the serial prefix number of the instrument in
which A5 is installed. Module assembly A5 is added for Option 001 or 003. Consequently, the A5 series
number may not be the same as the instrument serial prefix number.
Page 6-33, Table 6-3, Option 001 Replaceable Parts:
Add "(SERIES 1840)" to Description of A5 (05061-6118) Digital Divider Module.
Page 6-35, Table 6-3, Option 001 Replaceable Parts:
Add “ (SERIES 1840)" to Description of A5A2 (05061-6014) circuit board assembly.
Change A5A2C13 from 0140-0202 (15 PF) to 0160-219 ; C: FXD MICA 10 PF 5% 300VDCW; 28480; 0160-219 .
Page 8-21, Figure 8-13, A5 Block Diagram:
Change A5 series number to SERIES 1840.
Page 8-21, Figure 8-14, Part of A5 Schematic Diagram;
Page 8-23, Figure 8-15, Part of A5 Schematic Diagram; and
Page 8-25, Figure 8-16, Part of A5 Schematic Diagram:
Change A5 series number at top of diagrams to SERIES 1840.
Page 8-23, Figure 8-15, A5A2 (05061-6014) Schematic Diagram:
Add SERIES 1840 at top of A5A2 schematic diagram.
Change value of A5A2C13 from 15 to 10 pF.
CHANGE 4 (A2 SERIES 1848) (OPTIONS 002 or 003)
NOTE: The following change for A2 series number does not affect the serial prefix number of the instrument
in which A2 is installed. Circuit board assembly A2 is added for Option 002 or 003. Series 1848 circuit boards for
A2 will not be the same as the instrument serial prefix number.
Page 6-30, Table 6-2, Option 002 Replaceable Parts:
Change A2 series number from 1 36 to 1848.
Change A2C5 and A2C from 0180-2614 to 0180-0113 under "HP Part Number ” and "Mfr Part Number ”
from 150D10 X903052 to 109D10 C2030T2.
Page 8-13, Figure 8-10, A2 (05061-6019) Schematic Diagram:
Change A2 series number (top of diagram) from 1 36 to 1848.
CHANGE 5 (1852A) (STANDARD INSTRUMENT)
See NOTE at nd of CHANGE 10.
Page 6-5, Table 6-1, A3 Replaceable Parts:
Add "(SERIES 1852) ” to Description of A3 (05061-6108).
Add "(SERIES 1852) ” to Description of A3A1 (05061-6106).
Change A3A1C12 from 0160-093 (1000 pF) to 0160-05 3; C: FXD CER 4 00 pF ± 20% 100 VDCW; 28480;
0160-05 3.
Add A3A1C54; 0160-2055; C: FXD CER 0.01 pF +80-20% 100VDCW; 28480; 0160-2055.
Add A3A1R40; 0 5 -0924; R: FXD ELM IK OHM 2% 0.125W TC= 0±100; 24546; C4-1/8-TO-911-G.

MANUAL CHANGES MODEL 5061A Page 10
CHANCE 5 (1852A) (STANDARD INSTRUMENT) (Continu d)
of R20 and the junction of L2 and C12.
Tabe 1. A5A4 Part No. 05061-6152 Repaceabe Parts
DESCRIPTION HP PART NUMBER
05061-6152
0140-0196
1820-1437
1854-0005
0757-0280
0757-0283
0757-0442
2100-0896
ASSY: SWITCH CIRCUIT BOARD (SERIES 1904)
C: FXD MICA 150 pF 5% 300VDCW
IC: TTL DUAL MONOSTABLE MVB/SCHMITT-TRIGR
TSTR: NPN SI 2N 08
R: FXD FLM 1K OHM 1% 1/8W
R: FXD FLM 2K OHM 1% 1/8W
R: FXD FLM 10K OHM 1% 1/8W
R: VAR WW 15K OHM 1-TURN TOP-ADj
REFERENCE
DESIGNATION
A5A4
A5A4C1*
A5A4IC1
A5A4Q1
A5A4R1
A5A4R2
A5A4R3
A5A4R4
Page 8-19, Figure 8-13, A5 Schematic Diagram:
Change A5 from SERIES 1840 to SERIES 1904.
Replace A5A4 schematic diagram with diagram in attached Figure 3 for A5A4 Part No. 05061-6152 (SERIES 1904
circuit board assembly.
Replace A5A4 component locator illustration with new illustration in attached Figure 4.
Page 8-21, Figure 8-14, Part of A5 Schematic Diagram:
Page 8-23, Figure 8-15, Part of A5 Schematic Diagram; and
Page 8-25, Figure 8-16, Part of A5 Schematic Diagram:
Change A5 series number at top of diagrams from SERIES 1840 to 1904.
NOTE The new A5A4 circuit board assembly uses a potentiometer for adjustment in place of a variable capacitor.
The adjustment procedure given in the Operating and Service Manual for A5A4 is the same for either
assembly.
Page 8-15, Figure 8-11, A3 Schematic Diagram:
Change "(SERIES 1640A)" at top of A3 and A3A1 schematics to (SERIES 1852).
Add 0.01 pf capacitor (C54) in parallel with electrolytic capacitor C10.
Add 1000 ohm resistor (R40) in series between the arm
Change the value of C12 from 1000 pF to 0.004 /xF.
CHANGE 6 (1904A) (STANDARD INSTRUMENT)
See NOTE at nd of CHANGE 10.
Page 6-12, Table 6-1, A8 Replaceable Parts:
Add "(SERIES 1904)" to A8 (05061-6095) Description.
Add "(SERIES 1904) ” to A8A1 (05061-6096) Description.
Change "HP Part Number" for A8A1C9, C10, and C22 from 0180-0113 to 0180-2614.
Change "Mfr Part Number ” for A8A1C9, CIO, and C22 from 109D10 C2030T2 to 150D10 X903052.
Page 8-33, Figure 8-19, A8 Schematic Diagram:
Change "SERIES 1244A" at top of A8 schematic to "SERIES 1904".
Add SERIES 1904 at top of A8A1 schematic.
Page 6-24, Table 6-1, Replaceable Chassis Parts:
Change C5 from 0180-0090 (1000 /xF) to 0180-28 ; C: FXD ELEC 2400 /xF + 5-10% 50VDCW; 28480; 0180-28 .
Page 8-51, Figure 8-23, Schematic Diagram:
Change C5 from 1000 to 2400 /xF.
CHANGE 7 (A5 SERIES 1904) (OPTIONS 001 or 003)
NOTE: The following change for A5 series number does not affect the serial prefix number of the instrument
with A5 added for Option 001 or 003. The series number on the A5 module assembly may not be the same as the
instrument serial prefix number.
Page 6-33, Table 6-3, Option 001 (A5) Replaceable Parts:
Change A5 (05061-6118) series number from 1840 to 1904.
Page 6-3 , Table 6-3, Option 001 (A5A4) Replaceable Parts:
Change A5A4 (05061-6033) and all components for this assembly with A5A4 Part No. 05061-6152 and com 
ponents in attached Table 1.