The table also shows that the AT35670A A100 FDD +5V supply and an additional DISK IN line are via wires used for Ground connections on a standard FDD ~ As all grounds on a standard FDD and the Gotek are connected together this would short the +5V if these devices were fitted unmodified The table above was derived from data for a standard FDD and sections 9≣4 and 9≣5 of the HP35670A service guide ~ Apart from the introduction of the additional connections marked in Magenta the difference between the FD325HF C558 A100 Disk Drive and the Gotek standard FDD pinout is simply a reversal of the 34pin connector It fitted okay and did not look out of place apart from red LEDs but it needed a 5V supply and checking the pinout of the Gotek and the FD325HF(C558) revealed. The front top edge of the emulator was fitted with some 2mm black foam tape to close an odd looking gap This is the Gotek emulator fitted on the HP35670A FDD carrier ~ The data connector is offset to the middle and further forward and although the ribbon cable reached from the mother board it was tight so white heat shrink was fitted over the tab shown because it was surprisingly sharp edged for an internal part

The Floppy Drive is a TEAC model FD235HF C558 which is a special version that has a +5V power supply within the data cable as described in this advert under 'Another option'Įarly versions of the HP35670A may have a standard FDD ~ I once had one of the first HP prototypes which was full of 'cut and strap' connections but I can not recall if the FDD had a separate power connector or not ~ it was long ago Pictured is the FDD in my HP35670A which is actually a later Agilent version made in Malaysia with a black fronted FD which you may have noticed has no 4pin power connector on the left side Using a USB memory stick directly on the analyser as if it were in a FDD should be a good feature but in practice getting the 'cheap' Gotek emulator to work was not that simple ~ Apart from a non standard FD interface on my HP35670A the Gotek emulator has little support and the green LED indicated nothing useful Several years ago I managed to get the 16bit windows 2000 programs I use with the HP35670A analyser to run in 64bit windoze 10 using WineVDM and retired an old desktop that had a floppy drive ~ I then stored 35670A files in the analyser and down-loaded them via a USB GPIB lead but the analyser had to connect to a PC via a USB cable It's 2020 and corona virus lockdown in the UK lets me start and sometimes even finish some long overdue projects like putting a USB Floppy Disk Drive emulator in my trusty HP35670A (Agilent AT35670A) FFT signal analyser ~ What should have been a simple purchase and fit project turned out to be more interesting due to a non standard TEAC Floppy Disk Drive (FDD)

Usb floppy emulator program