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Thread: RX02 Difficulties

  1. #1

    Default RX02 Difficulties

    Hi all,

    New to this forum - usually over on classiccmp mailing list.

    I was recently sent an M8029 RX02 controller which I have installed in my PDP-11/73. To test things I have been trying to dump the contents of some disks with VTserver. Originally VTserver would immediately throw an error, but this turned out to be incorrect DIP settings on the RX02 controller board (inside the drive). For the M8029 they should be 1=off,2=on, so now I am little further. So, now I get:

    Code:
    Tape record n from device xx is written as xx(0,0,n)
    Disk drive xx is written as xx(0,0,0)
    
    Enter name of input record/device: rx(0,0,0)
    Enter name of output record/device: vt(0,0,1)
    
    Opened copy.out read-write
    and then it just hangs. The disks are definitely spinning since the small registration(?) hole on the floppy rotates out of sight.

    Here is the status of the CSR and the error register after an init:

    Code:
    17777170/104040
    17777172/10214
    The most significant bit of the CSR would suggest that there is an error but I am not too sure about the second register. I attempted to decode it and it said density error. These are RX02 drives and RX02 floppies so I am unsure!

    Can anyone offer any advice?

    Thanks,
    Aaron.

  2. #2
    Join Date
    Jan 2010
    Location
    Central VA
    Posts
    3,405

    Default

    I'd start with the RX XXDP routines. My RXV21 (M8029 on the handle) ended up having a bad CSR latch, the XXDP routines caught it pretty much immediately. You can boot them off of simulated TU58. AK6DN has bootable TU58 images on his site, you should be able to find one with the RX routines.

    Keep in mind the UNIX conventions for RX drive naming are a bit funny. From the `rx.c` source:

    Code:
      31:  *	Layout of logical devices:
      32:  *
      33:  *	name	min dev		unit	density
      34:  *	----	-------		----	-------
      35:  *	rx0a	   0		  0	single
      36:  *	rx1a	   1		  1	single
      37:  *	rx0b	   2		  0	double
      38:  *	rx1b	   3		  1	double

  3. #3
    Join Date
    Nov 2014
    Location
    Chicagoland
    Posts
    119

    Default

    Quote Originally Posted by asj View Post

    and then it just hangs. The disks are definitely spinning since the small registration(?) hole on the floppy rotates out of sight.

    Here is the status of the CSR and the error register after an init:

    Code:
    17777170/104040
    17777172/10214
    The most significant bit of the CSR would suggest that there is an error but I am not too sure about the second register. I attempted to decode it and it said density error. These are RX02 drives and RX02 floppies so I am unsure!

    Can anyone offer any advice?

    Thanks,
    Aaron.

    A quick lookup of the RXDB register is that you have an AC LOW, Drive Ready and INIT Done are set. The AC LOW is an indication that the RX02 Subsystem may have power problem, either RXAC L line is asserted or perhaps a cable issue. A common problem is to have a cable accidentally reverse connected on one end.

    Jerry

  4. #4

    Default

    Thanks both - I'll try XXDP tonight when I get home and give an update.

    Aaron

  5. #5

    Default

    Okay so I have just ran the the logic diagnostics ZRXFBO on XXDP.

    Code:
    DR>STA
    
    CHANGE HW (L)  ? N
    
    CHANGE SW (L)  ? N
    
    CZRXFB0 SYS FTL ERR  00040 ON UNIT 00 TST 011 SUB 000 PC: 003476
     CSR BITS - LGC TST
      AC LOW FATAL ERROR
          REG ACTUAL=000000
          REG EXPECT=000000
    
      POSSIBLE FAILING "FRU'S":
                INTERFACE - M8029
    
      UNIT#0 RXCSR=000000 RXESR=000000 CMD=000000 ->
     ->NO PWR, CABLED BACKWARDS, STRAPPED RX01, PDP-8
     DROP UNIT#0 FROM TEST
    
    PASS ABRTD THS UNIT
    CZRXFB0 SYS FTL ERR  00040 ON UNIT 01 TST 011 SUB 000 PC: 003476
     CSR BITS - LGC TST
      AC LOW FATAL ERROR
          REG ACTUAL=000000
          REG EXPECT=000000
    
      POSSIBLE FAILING "FRU'S":
                INTERFACE - M8029
    
      UNIT#1 RXCSR=000000 RXESR=000000 CMD=000000 ->
     ->NO PWR, CABLED BACKWARDS, STRAPPED RX01, PDP-8
     DROP UNIT#1 FROM TEST
    
    PASS ABRTD THS UNIT
    CZRXFB0 EOP    1
        2 TOTAL ERRS
    First drive 0 clunks and then drive 1 clunks, so I am pretty sure the cable is not backwards. I've checked power on my Q-bus backplane, healthy 12v and 5v rails. Checked the power in the RX02 drive, healthy 25v, 5v and -5. So, not sure if it is right about "AC Low". Makes me wonder if there is an issue with the controller?

    Advice much appreciated.

    Thanks,
    Aaron.

  6. #6

    Default

    Also, here are some images of the insides.

    http://aaronsplace.co.uk/private/pic...sides/full.jpg
    http://aaronsplace.co.uk/private/pic...ides/logic.jpg
    http://aaronsplace.co.uk/private/pic...driveboard.jpg

    I can't find any documentation about how things should be wired, and things are fairly ambiguous. For example, the four black connectors at the top of the logic board have gaps between them, and one is more to the right than the other. There are the other pins, which say HD0 and HD1 near them. No idea.

    Although, based on what XXDP said I wouldn't be surprised if there was an issue with the M8029, but I am unsure because the drives made nice clunking sounds when it started the tests.

    Hopefully my posts will stop getting stuck in the moderation queue soon...

    Thanks!
    Aaron.

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