> On Dec 8, 2017, at 5:17 PM, Aaron Jackson <aa...@aaronsplace.co.uk> wrote: >> >>>> On Dec 8, 2017, at 12:53 PM, Aaron Jackson via cctalk >>>> <cctalk@classiccmp.org> wrote: >>>> >>>>> On Fri, Dec 8, 2017 at 3:03 PM, Aaron Jackson <aa...@aaronsplace.co.uk> >>>>> wrote: >>>>>> >>>>>> Manual says it should be S1=off, S2=on for RX211 and RXV21 >>>>> >>>>> In the photo, I think S1 is on and S2 is off. Check them with an >>>>> ohmmeter if in doubt! >>>>> >>>>> -tony >>>> >>>> Yes - you are right. I switched them back to how they were when I got >>>> the drive. I think one of the switches was half down because XXDP >>>> actually does something now. >>>> >>>> Most of the tests now look something like this: >>>> >>>> CZRXFB0 DVC FTL ERR 00034 ON UNIT 00 TST 031 SUB 000 PC: 003476 >>>> SECTOR ADR - LGC TST >>>> SECTOR ADDRESS ERROR >>>> EXPECTED SECTOR=18. >>>> TARGET SECTOR=17. >>>> >>>> I suppose these should match? >>>> >>>> Starting to think I might need to confuse myself with my logic analyzer >>>> and the RX02 control board. >>>> >>>> Thanks, >>>> Aaron. >>> >>> To isolate the problem further, try to see if any of the errors follow >>> the media as you move them between drives. >>> >>> If the same errors occur on both drives, regardless of media then the >>> RX02 system board or perhaps the Qbus controller are at fault. >>> The field maintenance prints should allow you to trace the fault down >>> a bit further, with or w/o a logic analyzer. >>> >>> How many different types of errors do you see? >>> >>> Jerry >> >> Thanks for the info Jerry. >> >> I get read errors, data errors, density errors, sector addressing >> errors. Probably every kind of error xxdp can give :) >> >> Please see this link if you are interested: >> >> https://aaronsplace.co.uk/private/o/48859c14f6a619a5316d6af37d60579c.txt >> >> I will take a proper look through the field manuals tomorrow, and also >> try what you suggested with trying the same media in both drives. >> >> Thanks, >> Aaron. > > > When you have many errors it can be hard to separate the primary fault(s) > from the knock-on errors. > The M7745/M7744 or Media Errors dominate the entries. > > 1) Try to verify the media is a DEC 8 Inch formatted RX02 or RX01 if you do > not know the source of the > the disks. The disk should have only 1 hole punched for index on the > media itself. Even if it is > a DEC Brand, there’s still possibility that the media has been exposed > to strong magnetic fields. > > I have not seen much natural bit-rot on my floppy media, but YMMV. If > could find someone local > with RX02 drives to confirm your media, that would also help rule out > some things. > > Many third party drives and controllers that were DEC compatible also > had the ability to do a > low level format of media, something the native RX02 did not. So if > the media type is correct, but > the format is not, they may be salvageable (with complete loss of > original data). > > 2) Check the connections between the drives and controllers. Gently clean > contacts, especially anything > gold plated. Getting clean signals from the floppies is critical if the > RW electronics are to function. > > 3) Try and contrast to the other drive as previously covered. > > This will help rule out a few things and provide some better direction. > > > Jerry
Thanks Jerry. That was very helpful. Found a stray piece of metal lying across the board next to an AND gate, which is slightly disconcerting. Possibly a stray wire clipping. Both drives pass the diagnostics. It's strange though, if I try to dump using vtserver using a floppy which passed the diagnostics, it fails. So, not sure. Will have to investigate a bit more. Thanks again, Aaron.
