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HP 3488A SWITCH / CONTROL UNIT
For Sale
Four HP 3488A's were acquired as part of a 'Job Lot'. The 3488A consists of a mainframe, keyboard, display, power supply, controller and a computer interface.  

The mainframe provides 5 slots for optional plug-in cards and is used to switch various analog signals in R&D and Production applications. The 3488A can be operated either from a remote computer program via HP-IB, or manually from the front panel. These cost $1,400 each in 1987.
 
Front Panel
Rear Panel with HP-IB Card and slots for 5 plug-in cards
There are 6 plug-in cards available: 44470A 10 Channel Relay Multiplexer Card; 44471A 10 Channel General Purpose Relay Card (see below); 44472A Dual 4 Channel VHF Card; 44473A 4 x 4 Matrix Switch Card; 44474A 16 Channel Digital I/O Card; 44475A Breadboard Card; 44476A/B Microwave Switch Module; 44477A Form C Relay Module.


December 2011

Downloaded Service Manual with circuit diagrams and Operating, Programming & Configuration Manual. Stripped down and cleaned up units, all are in good condition and they are easy to dismantle.

Front Panel Display & Controls
Front Panel Controls
The front panel is connected to the backplane by a 34 way ribbon cable.
The HP-IB Controller Card is plugged into the bottom right hand side position next to the mains input, filter & fuseholder.
The HP-IB Controller Card
Backplane Connectors and Mains Transformer with Voltage Selector Switch
Power Supply Unit providing +5.1V at 4A max. This uses a ST Microelectronics DC-DC switching converter with thermal, short-circuit and overload protection. Downloaded a data sheet.

Powered-up and all 4 power supplies are working with the TEST button checking all the display characters then finishing with 'Self Test OK'.

One of the 3488A's had a HP 44471A 10 Channel General Purpose Relay Card fitted.
With the RF screen removed the 10 relays can be seen. Full details are in the HP Manuals.

The 3488A with the plug-in cards provides a useful switching system in local mode and also in remote mode with HP-IB (see HP-IB Interface Bus for details). 


August 2014 

These 3488A's provide a lot of useful parts for another project.  As I currently have no real need for these units they are FOR SALE.

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