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How can I clear the memory on an 8566B, 8567A, or 8568B Spectrum Analyzer for security reasons?

The 8566B, 8567A, and 8568B Spectrum Analyzers are two-section instruments, each consisting of an RF Section (85660B, 85670A, and 85680B, respectively) and an 85662A IF-Display Section. The main processor for each instrument is an 8 MHz, 16-bit Motorola 68000, which is located in the RF Section along with:

32 kBytes of nonvolatile CMOS RAM*

  • 4x64 kbits CMOS Static RAMs
  • approximately 24 kBytes of CMOS RAM* are user-accessible for downloadable programs (DLPs) and trace arrays
  • RAM contents preserved for >3 years by 3.5V Lithium battery

96/128/192 kBytes of EPROM*

  • spectrum analyzer main processor firmware stored in UVEPROMs
  • EPROMs can be 6x128 kbits, 4x256 kbits, or 6x256 kbits

The display processor for each instrument is located in the HP 85662A IF-Display Section and includes:

  • 18 kBytes of PROM (128 kbits + 16 kbits)*
  • 8 kBytes of CMOS RAM (64 kbits)*

* measured as 8-bit bytes

The EPROMs and PROMs contain the instrument's main processor and display processor firmware, and determines instrument functionality.

The non-volatile (battery-backed) RAM is used to store the seven SAVE/RECALL registers, downloadable programs (DLPs), and instrument calibration data (values for error correction, preselector peaking, and harmonic mixing conversion loss). Approximately 24 kBytes of this non-volatile RAM are reserved for downloadable programs and trace arrays; this block is called User Memory. RAM located in the 85662A is called Display Memory, and is shared by the main processor and the display processor. This RAM is cleared when the instrument LINE switch is set to STANDBY and when the 85662A IF-Display Section is disconnected from LINE power.

Display Annotation Blanking

[SHIFT] THRESHOLD [OFF] (KSo) blanks the annotation on the CRT display. Display annotation blanking is not retained in or affected by the SAVE/RECALL registers. Keying in [SHIFT] THRESHOLD [ENTER]

(KSp) re-enables the display annotation. [INSTR PRESET] or [2-22 GHz] re-enables the CRT annotation and writes over the present state with the instrument's preset state.

Display Blanking

[SHIFT] TRACE B [CLEAR-WRITE] (KSg) turns off the CRT beam, blanking the entire CRT display. Display blanking is not retained in or affected by the SAVE/RECALL registers.  Keying in [SHIFT] TRACE B [MAX HOLD] (KSh) re-enables the CRT beam. [INSTR PRESET] or [2-22 GHz] re-enables the CRT beam and writes over the present state with the instrument's preset state.

Frequency Offset

[SHIFT] [CENTER FREQUENCY] (KSV) specifies the frequency offset for all absolute frequency readouts such as center frequency. Frequency offsets are retained in the SAVE/RECALL registers. [INSTR PRESET] or [2-22 GHz] clears any frequency offset and writes over the present state with the instrument's preset state.

Clear SAVE/RECALL Registers and User Memory

The ERASE command clears all seven SAVE/RECALL registers and any downloadable programs (DLPs) in User Memory. To manually execute the ERASE command, key in:

  1. [SHIFT] ) [RECALL]
  2. [SHIFT] E [AUTO]
  3. E [AUTO]
  4. R [MKR => REF LVL]
  5. A [AUTO]
  6. S [SIGNAL TRACK]
  7. E [AUTO]
  8. [NORMAL]
  9. [SHIFT] 1 [kHz/mV/msec]
  10. [SHIFT] 1 [Hz/uV/usec]

The instrument's preset state is then written into each of the SAVE/RECALL registers, and the present instrument state is overwritten with the instrument's preset state. Note that the ERASE command does not clear instrument calibration data (stored values for error correction, preselector peaking, and harmonic mixing conversion loss).

The DERASE command (8566B firmware revision 10.10.89 and later) is a more complete version of the ERASE command that clears all RAM by writing all 1's and then all 0's into each memory location. This clears the display (trace) memory, the seven SAVE/RECALL registers, all instrument calibration data (stored values for error correction, preselector peaking, and harmonic mixing conversion loss), and any downloadable programs (DLPs) in User Memory. To manually execute the DERASE command, key in:

  1. [SHIFT] ) [RECALL]
  2. [SHIFT] E [AUTO]
  3. D [AUTO]
  4. E [AUTO]
  5. R [MKR => REF LVL]
  6. A [AUTO]
  7. S [SIGNAL TRACK]
  8. E [AUTO]
  9. [NORMAL]
  10. [SHIFT] 1 [kHz/mV/msec]
  11. [SHIFT] 1 [Hz/uV/usec]

The power-up self-test is initiated, and then the instrument's preset state is written into each of the SAVE/RECALL registers and the present instrument state is overwritten with the instrument's preset state. The BATTERY message will appear in the spectrum analyzer display, indicating that non-volatile RAM has been cleared.

Deleting the 8566B/8567A/8568B Battery

The internal lithium battery can be removed (unsoldered) from the A15 Controller Assembly to cause all RAM memory to be cleared when the spectrum analyzer LINE switch is set to STANDBY or the RF Section is disconnected from LINE power. A jumper wire must be added to ensure that the RAM memory clears in a reasonably short period of time. The BATTERY message will appear on the spectrum analyzer display at turn-on after RAM has been cleared.
    
For A15 Controller Assembly, Part Numbers 85660-60209 and 85680-60180: unsolder battery A15BT1 and replace A15CR1 with a short jumper wire.
    
For A15 Controller Assembly, Part Numbers 85660-60245, 85660-60263, 85680-60182, 85680-60202, 85680-60217, and 85670-60002:
unsolder battery A15BT1 and replace A15Q2 with a short jumper wire connected between the emitter (+5VF) and the collector (VRAM).

Security Recommendations

Cleared Operator in a Controlled Area:

Use annotation blanking or display blanking to conceal classified information.

Operator in Proximity to an Uncontrolled Area:

Use annotation blanking or display blanking to conceal classified information. If no downloadable programs (DLPs) have been stored in user memory, preset the spectrum analyzer ([INSTR PRESET] or [2-22GHz]) and save the spectrum analyzer's preset state into each SAVE/RECALL register to declassify the instrument. If downloadable programs (DLPs) have been stored in User Memory, execute the ERASE (or DERASE) command to declassify the instrument. If the internal battery has been removed (Special Option F11), the operator can set the LINE switch to STANDBY to declassify the instrument.

Uncleared Operator in an Uncontrolled Area:

A local lockout may be programmed over the GP-IB to disable the spectrum analyzer front panel so that the operator cannot alter any of the parameters.

The spectrum analyzer must have the internal battery removed. Use annotation blanking or display blanking to permanently conceal the classified frequency information. Set the LINE switch to STANDBY to declassify the instrument.

Moving a Spectrum Analyzer from a Controlled Area to an Uncontrolled Area:

If no downloadable programs (DLPs) have been stored in User Memory, preset the spectrum analyzer ([INSTR PRESET] or [2-22 GHz]) and save the spectrum analyzer's preset state into each SAVE/RECALL register to declassify the instrument. If downloadable programs (DLPs) have been stored in User Memory, execute the ERASE (or DERASE) command to declassify the instrument. If the internal battery has been removed, the operator can set the LINE switch to STANDBY to declassify the instrument.