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HP 141T DISPLAY SECTION
EXTERNAL CONNECTIONS
These 2 special D-type connectors on the Rear Panel are labelled AUX A (J8) and AUX B (J10).

They are wired to J9 and J11 inside the 141T and mate with the HP 8553B RF Section, HP 8554B RF Section or HP 8555A RF Section. For details see HP 141T Display Section Internal Connections.

Externally, AUX A is connected to either the HP 8443A Tracking Generator Counter or the HP 8444A Tracking Generator and AUX B is connected to the HP 8445B Automatic Preselector.

Special cable 08443-60009 for connecting AUX A to the 8443A Tracking Generator. This cable is available from GLK Instruments.

Special cable 08444-60017 for connecting AUX A to the 8444A Tracking Generator. This cable is available from GLK Instruments.

Additional BNC to BNC cables are required to connect the 8554B (2 required) or 8555A (3 required) to the 8444A.

Special cable 08445-60007 for connecting AUX B to the 8445B Automatic Preselector. This cable is available from GLK Instruments.

Special cable 08445-20022 for connecting 8445B output to 8555A input. This is a rigid N-type coaxial cable. Very difficult to obtain!

RF & LF
 Plug-In Units 
Frequency
Range
Tracking
Generator
Special
Cable
8553B
RF Section
1kHz to 110MHz 8443A  08443-60009 
8554B
RF Section
 100kHz to 1,250MHz  8444A 08444-60017
8555A
RF Section
10MHz to 18GHz 8444A
 up to 1,300MHz 
08444-60017
8556A
LF Section
20Hz to 300kHz Included None
NOTE: Only the 8555A will operate with the 8445B Automatic Preselector.

AUX A Connections
J8 Top

8443A Functions
8444A Functions
A1
n.c. Guide Pin Guide Pin
A2
RD  1st Local Oscillator 
200MHz to 310MHz
 3rd Local Oscillator 
500MHz
A3
OR Scan Voltage
0V to 10V
Scan Voltage
0V to 10V
A4
YL 2nd Local Oscillator
150MHz
Local Oscillator
47MHz
A5 GY 3MHz IF * Sweep + Tune/Full
Scan -5V to -10V
A6 BL 3rd Local Oscillator
47MHz
Tuning Stabiliser
Enable
A7 VL Centre: Blanking
Shield: Zero Scan
Centre: Blanking
Shield: Zero Scan
A8  n.c.  Guide Pin Guide Pin
J8 Bottom   8443A Functions 8444A Functions
NOTES:
The connecting cable to the 8444A only uses the A2 500MHz connector.
A4 and A6 are terminated in 50Ω.
* The 3MHz IF is not used on S/N <1144A.

If the special cables to the 8443A or 8444A are not used, then the A2 A4 & A6 outputs at Aux A should be terminated with the 08553-60122 50 Ohm Termination. This applies for all the RF Sections but is not required for the LF Section.

AUX B Connections
J10 Top

8445B Functions
A1
n.c. Guide Pin
A2
WH 50MHz IF
Pin 1
914 'A' Bit Band Code
Pin 7
924 YIG Tune Voltage
Pin 2 915 'B' Bit Band Code
Pin 8 925 not listed
Pin 3 916 'C' Bit Band Code
Pin 9 926 not listed
Pin 4 917 'D' Bit Band Code
Pin 10 927 not listed
Pin 5 918 'E' Bit Band Code
Pin 11 902 +20V
Pin 6 923 not listed
Pin 12 0 +20V Return
A3 BL  Sweep + Tune/Full Scan -5V to -10V 
A4 RD Per Division Sweep
A5  n.c.  Guide Pin
J8 Bottom   8445B Functions
NOTES:
All these connections will be investigated further when the individual units are tested, especially the connections marked not listed.
On the 8445B the coax connections for A4 and A2 are not fitted in the D-type connector.