The error signal was wire-or'ed through up to four drives, so it must be terminated somewhere - IIRC there was a Unibus terminator in the last drive, but it has been 45 years since I worked on them, the little grey cells are fading _\:-)
cheers, Nigel Nigel Johnson, MSc., MIEEE, VE3ID/G4AJQ/VA3MCU Amateur Radio, the origin of the open-source concept! Skype: TILBURY2591 nw.john...@ieee.org On 09/07/2020 20:02, Robert Armstrong via cctech wrote: > I have an 11/04 with an RK11-D. I have a couple of RK05s, but I > wanted to test the controller before I start working on the drives. > The PDP11 Diagnostic Handbook says that ZRKJ?? "checks only the > drive-independent logic of the RK11 controller. no drive is > needed..." I assumed that meant it was a diskless test, but now I'm > not sure that's true. Can anyone confirm or deny this? Does anyone > have a listing of ZRKJE0? > > My RK11-D has the BC11 drive cable plugged into the backplane, but > the free end of the cable is just lying on the floor. No drive is > connected. The test fails with > > RK11 LOGIC TEST I > MAINDEC-11-DZRKJ-E > > REGISTER NOT CLEARED > PC REGADD RECVD > 002560 177402 100000 > > 177402 is the RKER register and bit 15 is DRE - "Drive Error". > According to the manual this bit is set when the AC power to the drive > is lost, which given that I don't have a drive at all, doesn't sound > unreasonable. Continuing ZRKJ?? also gives > > REGISTER NOT CLEARED > PC REGADD RECVD > 002560 177404 140200 > > RKCS ERROR > PC WROTE READ > 002636 000002 140202 > > 177404 is the RKCS register and the first two bits are ERROR and HARD > ERROR. These are both set by the DRE bit in RKER and aren't really a > surprise. > > I'm starting to wonder if this diagnostic really works w/o a drive > attached, or if these errors are expected. > > Thanks, > > Bob >
