Power supply problem? Marc
> On Apr 30, 2024, at 8:58 AM, Dominique Carlier via cctalk > <cctalk@classiccmp.org> wrote: > > Hello everyone > > I need your help to identify an issue on my Diablo Model 40 Series. I don't > know where to look, it's so vast ! > > Here's the problem: > When RUN is activated, the drive begins its spin up and simultaneously > deploys the heads (normal) but instead of stabilizing them, the Head > Positioner receives a burst of reverse/forward micro signals. The heads > "vibrate", this creates an audible frequency "BRRRRRRRRRRRRRRRRRR", and it is > infinite, the heads are never loaded and the drive never reaches READY. > > At first I thought that perhaps the track zero sensor was defective or > something of the same order but when I disengage RUN mode, the drive unloads > the heads and they should be in a fixed position, here they continue to > reverse/forward but more slowly than in RUN mode. > Because the heads continues to mess around even in unload mode, this a priori > excludes alignment problems. > > Here is a video of that issue: > > https://youtu.be/HzzxLnSdEOg > > Other information, if I cut the power while the drive is in RUN mode, it does > not do an emergency retraction of the heads, related problem? > I was hoping for a power supply problem but all the voltages and even on the > main board cage seem ok (with a multimeter). > > If one of you had already encountered this problem of lack of head > stabilization and continuous reverse/forward on this type of drive? > > Thanks ! > > Dominique >
