> > From: Aaron Jackson > > > I have tried three controllers, two r/w modules and two servo > > controllers. I'm beginning to think the drive is fine and there is a > > problem with the RLV21 controller. > > Err, think you mean RLV12 QBUS controller board, right?
Woops, yes! I get mixed up with the RXV21. > Anyway, you've already tried ("three controllers") swapping that out? As in the logic controller inside the drive. I only have one RLV12 unfortunately. Although a friend has recently purchased one, so hopefully I can test with that soon. > If you have, perhaps there's a problem with a cable and/or the terminator? > > > However, at this point, sub-system swapping is probably not going to be the > best way to make progress. I think you're going to have to actually debug the > problem; i.e. dive in and work out what's happening wrong, and why, and trace > it back to the origin. > > Luckily, for this generation (and before), DEC produced wonderful technical > manuals, which go into full detail of how the thing works. With that in hand, > the investigative process is a lot easier; you don't have to work out how the > thihg works by looking at the prints, it's all laid out in detail. And tech > manuals for both the RL02 drive and RLV12 controller (EK-RLV12-TD-001) are > available online, as are the prints (MP01282 for the RLV12). > > So, I'd sit down with the RLV12 tech man and read through the section on the > drive<->controller bus (section 3.3). Then start looking at what the two are > saying to each other on the bus, and figure out what's actually going wrong. > From there, you'll know where the source of the problem is, and can chase it > further. > > I know this sounds like it would be time-consuming, but when you think about > the time/energy you've already put into swapping things around, chasing this > problem, it won't be. > > Noel I have been studying the technical description manual, and the schematics in quite some detail. I think it is time I hook up a logic analyser to the cable between the RLV12 controller and the drive to try and see what is going on during the initial seek. I have already checked to see if there is a 4.1MHz clock signal (there is). Thanks, Aaron.