3.5" floppy jumpers

On 28/11/2008 04:39, Curtis H. Wilbar Jr. wrote: See if Google can find you a document called 3fd0020a.pdf -- that's TEAC's config sheeet for the whole FD235 range. There are lots of models with different jumpers. That one is one of the dual 720K/1.44M 3xxx (old) versions.

HO determines whether it outputs a signal to tell the host controller whether the disk is DD or HD, normally on pin 2. HI determines whether it accepts a density select input on pin 2. LHI and HHI are something to do with the density select input on pin 2. They're definitely related to HI, but I seem to recall having jumpers on all three on at least one drive. I'm pretty sure you jumper both or neither, never just one. I'm not sure what H on its own would be. HA tells the drive to determine density itself, from the HD hole sensor, instead of getting it from the host. Sometimes there's a number after the jumper name, like for DC. DC34 means the Disk Changed signal is on pin 34, while DC2 (on a few models) means it puts that signal on pin 2. FG is for Frame Ground; sometimes there's a jumper or solder link to connect it to the 0V DC supply. MD and MM usually refer to what turns the motor on: only when asserted with Drive Select, or any time the Motor On signal is active. Some Sony drives have jumpers to determine when they output index pulses (only when the drive is up top speed, or always). But if you only have a few, they're probably just the drive select jumpers.