11/44 scare

From: John Lawson <jpl15_at_panix.com>
Date: Sat Nov 9 18:01:00 2002

On Sat, 9 Nov 2002, Tony Duell wrote:

> > BUT: I have doc! I have Processor Manuals! I have the Technical Manual!
> > And, using ODT, I found that the system was trying to boot the ESDI drives
> > and failing. I'm so proud of myself - decoded the error codes, followed
>
> OK, what does the error code in from the ESDI controller's registers
> translate to?


  Unknown and unobtainable at this time; the card fails to respond at all
and the CPU times out and falls back into ODT. The failure indications led
me to the card, but I couldn't go farther. Such gross failures are usually
obvious, though... rather than the 'once every other third Tuesday except
April and leap years' type of fault.


>
> Does the ESDI controller manage to select a drive? (Meaning the bus
> interface and probably the on-board processor are working). Move the
> heads? Read anyting from the drive at all?
>

  As above (so below). It is possible that the address decoding circuits
have failed, or something in the grant chain, though I doubt that, due to
the fact that calling for a boot from an alternate drive (the RL02)
functioned normally. Otherwise, cabled to the drives or not, the CPU
traps out when this card is in the system. It's identical twin is now
performing properly in the machine, all is well.


> It might still be something has come loose when moving the machine. Have
> you re-seated any socketed ICs? And jumpers?
>

  Not yet, although I *do* have a recently-purchased quad-height extender
card (Thanx Bruce Lane!) so, at some future date, I will essay it's repair
and refurbishment. Also, I must launch a full-court-press search for the
documentation for this card, though parts of it are pretty obvious from
the chips and their placement on the board.

  Anybody got any info on a Dilog 626 ESDI Unibus Card????


  Thanks, Tony!

John.
Received on Sat Nov 09 2002 - 18:01:00 GMT

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