exxos's Atari, Amiga & retro forum

rubber_jonnie wrote: 09 Feb 2022 13:52 Is that a crystal/oscillator hanging off the edge of the PCB? Looks a bit ropey!!

BennehBoy wrote: 09 Feb 2022 13:58

rubber_jonnie wrote: 09 Feb 2022 13:52 Is that a crystal/oscillator hanging off the edge of the PCB? Looks a bit ropey!!

Yup, I think it's a factory mod too.

Good news is I resoldered the wire and now have comms with the drive. Bad news is that the spindle motor doesn't run, not sure yet if that's an electronics issue or the motor itself.

BennehBoy wrote: 09 Feb 2022 16:31 Been having a bit of a scope on the drive, the motor board (this is a direct drive motor) is getting +12v & +5v. I can also see that the motor activation line is getting driven high by the VIA chip when any activity is required, but the motor does not spin up.

A quick eyeball doesn't show anything obvious, but I'm going to check all the caps, diodes, resistors etc next. Fingers crossed it's not a motor winding - I'll figure out how to continuity check those later.

PXL_20220209_162716934.jpg

BennehBoy wrote: 09 Feb 2022 18:08 Afraid I don't have a spare to test, and yes I guess it is controlled by that IC. None of the passive stuff seems b0rked, and the motor coils have continuity. Without any schematic I'm a bit at a loss tbh.

BennehBoy wrote: 09 Feb 2022 19:10 I found this datasheet for that IC -> https://www.datasheetarchive.com/pdf/do ... rm=HA13431

Pin 2 seems to be what should initiate the motor starting or stopping, low=start, high=stop. So an inversion of what's coming from the CIA control line, tracing that line it looks to run through a transistor of some sort, and I never see the line be anything other than low at the motor IC (which you'd think would mean it would spin constantly?). I'll see if I can pull that transistor and test it.