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8643a_synthesized_signal_generator

HP 8643A

First Catalog 1992
Last Catalog 2001?
Frequency Range 0.252 - 1030/2060 MHz
Amplitude Range -137dBm to +13dBm

See Manuals section below

The 8643A signal generator is closely related to the 8644A/B, 8645A, 8664A, 8665A/B .

In that family, the 8644A, 8645A and 8665A were all released together in 1989 (see also HP Journal issue from October 89). The 8665B appeared in the 91 catalog. The 8643A, 8644B and 8664A appeared in the 92 catalog :

The HP 8643A 1 GHz/2 GHz and HP 8644B 1 GHz/2 GHz RF signal generators are replacements for the HP 8644A. […]

signal_generators:8643a:8643a_front.jpg

Specifications

  • 252 kHz to 1030 MHz
  • Electronic attenuator (PIN diodes)
  • AM, FM, pulse modulation
  • +13 dBm to -137dBm ; up to approx +15dBm overrange (increased harmonic distortion)

Options

  • 001 High stability time base with EFC
  • 002 2060 MHz doubled output
  • 003 Rear panel input/output
  • 004 Low noise option
  • 005 Electronic attenuator (N/A with Option 002)
  • 008 Pulse modulation
  • 009 Specified VOR/ILS
  • 010 Reduced leakage configuration
  • 011 2 GHz internal frequency counter
  • 907 Front handle kit (5061-9690)
  • 908 Rack flange kit (5061-9678)
  • 909 Combined front/rack flange kit (5061-9684)

(these two are from some test equipment vendor's page, I could not find an official source)

  • H02 Improved Performance from 252 kHz to 1030 MHZ (?)
  • H05 Improved Max Power / AM / FM / Pulse Operation and Firmware
  • K01 ??

Manuals

  • HP 8643A, 8644B Quick Reference Guide. First edition 08643-90019 / 08643-90020 Download @Keysight
  • HP 8643A, 8644A/B, 8645A, 8664A, 8665A/B Assembly Level Repair , PN 08645-90145 . (Serial numbers: <= 3246A (8643A), <= 3203A (8644*/8645), <= 3744A (8664/8665*))Download @Keysight, or Download here
  • HP 8643A and 8644B Synthesized signal generator. (Serial numbers 3147A and above). User's guide, PN 08643-90019 (why is it the same PN the quick ref guide ?) Download @Keysight , or Download here
  • HP 8643A, 8644B, 8664A, 8665A/B Data Sheet , 5091-2580E, Download here
  • 08643-90022 Installation notes, Firmware Upgrade Kit 08643-61018 for the HP 8643A Synthesized Signal Generator Download @Keysight

Firmware versions

Revision code Date code1) ROM Partno 08643-X Reason for change
3.3.0 2908 87001-87004 Original release of the firmware.
4.0.0 3203 87101-4 Adds firmware to control the new timebase configuration. Corrects the following special functions: 160, 162, 171, 320, 331. Adds special 328: user enabled transient error interrupts.
4.2.0 3409 87201-4 Fixes center frequency accuracy in FM Mode. Corrects counter diagnostic error 18999.
4.2.1 3449 87301-4 Corrects the calibration error due to the differences between the ALC EEPROMS. Added a diagnostic latch to the ALC module. Fixed a potential divide-by-zero error in the attenuator driver module.

8643A DCU ROM 4.2.1 @ KO4BB

repair & misc info

  • The DCU card has a Ni-Cd battery pack, prone to leaking and damaging PCB. Symptoms of memory loss : unit does a self-calibration (5-7 minutes) on every power-up.
  • The RAM battery voltage is routed through the motherboard, so removing the DCU clears RAM automatically (and causes a self-calibration on next powerup).
  • A few RIFA caps, and leaky LXF / TXF electrolytics in the power supply modules.
  • Look out for shorted tantalum caps (Kemet T396 series, 3 legs) where subjected to inrush current (i.e. power entry in the various modules)
  • The attenuator card has an EEPROM holding calibration data

Youtube repair videos :

Photos of internal modules

signal_generators:8643a:8643a_inside.jpg signal_generators:8643a:8643a_dcu_08645-60101.jpg signal_generators:8643a:8643a_attenuator_08644-61109_or_08643-60205.jpg

1)
XXYY: year=1960+XX, week=YY
8643a_synthesized_signal_generator.txt · Last modified: 2022/01/07 21:59 by fenugrec

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