HP 209A Operating And Service Manual page 47

AppendixC
~MANUAL
BACKDATING CHANGES
Model209A
Sine/Square Oscillator
Manual Serial Prefixed: 818-
This manual backdating sheet makes this manual applicable to earlier instruments.
Instrument-eomponent values that differ from those in the manual, yet are not listed in
the backdating sheet, should be replaced using the part number given
in
the manual.
Model209A
I nstrument Serial Prefix
Make Manual Changes I nstrument Serial Prefix Make Manual Changes
818-00800 and below No.1
818-00950 and below No.l,2
818-01876 and below No.1, 2, 3
CHANGE NO.1 (818-00800 and below)
Table 6-1: Delete Al C30*.
Figure 7-1 : Delete Al C30*.
CHANGE NO.2 (818-00950 and below)
Table 6-1 :
Change AICR6 to "Diode: silicon" -hp- Part No. "1902-0041.
Change Al R43 to "R: fxd, 18 kilohms" -hp- Part No. 0684-1831.
Figure 7-1:
Show Al CR6 as a conventional diode.
Change the value of Al R43 to 18 kilohms.
NOTE (818-01776 and below)
Replacement of Al CR12
Tunnel diode (-hp- Part No. 1912-0009) is the replacement part for -hp-
Part No. 1912-0026. The ANODE and CATHODE connections of the new
diode are reversed with respect to the discontinued diode (see below
figure).
ANODE--Q:J-- CATHODE ANODE--[]-- CATHODE
..... 4 _ - - - - D O T PC BOARD---.............
NEW DIODE
(-hp- Part No. 1912-0009)
Case Marked IN3712GE
DISCONTINUED DIODE
(-hp- Part No. 1912-0026)
Case Marked TD712GE
The replacement diode should be placed in the circuit with the case
(CATHODE) away from the dot on the Al printed circuit board.
www.HPARCHIVE.com