Gotek and 7417 IC replacements

[davisgw]

Hello all,
I've been modifying my 2 Superboard II systems to be compatible with GOTEK floppy emulators. The reason this could be problematic is that all my floppy drives have removable resistor packs and when removed present minimal loading on the control lines, whereas the GOTEKs that I have do not have removable resistors, making them incompatible with a floppy or a second GOTEK because drive select lines are overloaded. So rather than modify the GOTEKs I decided to add more robust drivers to the floppy interface cards...except that 7417 ICs are scarce and expensive when you find any (also replacements for the 600 and 610 boards might be needed). Eventually I decided to try 7407 ICs as replacements since they are pin compatible, cheap, and easy to find. My first upgrade went smoothly and works great! So I am currently modifying the second system.

[Thomas]

The pull-up resistor inside the GOTEK is 1k. A very "light" pull-up.
In addition, Ohio Scientific spend two 7417 in parallel for each select lines, so plenty of driving capacity.
I never had any problems with my 610 and two GOTEK's attached.
Maybe one of your 7417 was damaged and caused this effect. But good to hear, that a more common 7407 is a good replacement.

[davisgw]

No, the problem is with a Gotek AND an old floppy drive on the same interface. And I was driving the Motor ON and Drive Select 1 lines with a 7400 IC because I had no open collector drivers. That worked fine with 2 floppies with pullups removed. That was solved with the 7407 open collector drivers.
I just thought some of the new owners of Superboards might know about 7407 as replacements to the 7417....