[IMSAI Guy] has an old HP 3488A Change Control Unit that he wants to dismantle for components ( see online video beneath the split ). The 3488A is really uncomplicated as much as HP exam equipment goes — a chassis that can maintain different varieties of relay cards and is programmable about GPIB. He notes up entrance that these are plentiful and affordable in the utilised check tools sector.
All-around the back of the unit is a card cage that accepts up to five option cards delivering
- 4×4 matrix switching
- on/off SPST switching
- switching alerts to a widespread bus
- VHF switching
- Electronic I/O signalling
The teardown is an fascinating glimpse into the reliable engineering structure of 1980s HP exam products. The solution playing cards are very well shielded, and have an intriguing back panel connector that breaks out the signals to screw terminals and supplies strain aid. The brains of switcher was a Motorola 6809 and connectivity was supplied by an Intel 8291A GPIB interface chip. The energy supply is reliable, and many of its sections can be reused on other jobs, such as the transformer and a beefy 20W DC-DC converter by ST. [IMSAI Guy] also scores a bunch of latching relays from the selection cards which will no doubt appear in helpful on foreseeable future initiatives.
These kinds of programmable relays can be incredibly helpful when creating automated check fixtures. There have been other answers for this as properly, back again in the day. Metrabyte ( purchased by Keithley, bought by Tektronix ) was a person organization that made a total line of switching interface modules that hooked up to your PC’s ISA bus. Omron also made available comparable items. Have you at any time desired banking institutions of programmable relays for your assignments? If so, allow us know your answer in the comments below.
