PDP-11/94-E

[Rod Smallwood]

On 03/06/2016 14:39, Noel Chiappa wrote:
>      > From: Rod Smallwood
>
> Ah, sorry about the previous message - hadn't gotten to this one yet! :-)
>
>      > 2. This is then followed by a request to type a letter B for boot , L
>      > for list and so on.
>      > 3. You can type any letter you like and it always goes to the same
>      > screen.
>
> I wonder if there's a case issue - have you tried upper and lower?
>
>      > 7. The Unibus adapter appears to pass all of its tests.
>      > I have two and they both perform the same.
>      > 8. The next slot to the UBA is an RX211 .. It is set to the standard
>      > addresses. Again I have two and the result is the same in both cases.
>
> Now that's _very_ interesting indeed. That cuts out a lot of the simple
> explanations (broken RX211 or KTJ11 - unless both of one of them are busted).
>
> One thing to check (sorry if you've already checked this) - did the address
> switches somehow get inverted (i.e. 'off' where it should be 'on', etc)? I'm
> too lazy to work my way through all the inversions in the address recognition
> logic (the print set is available online, Google "MP00626") to see whether
> 'off' means '1' or '0'; I couldn't find a manual for the RX211, which would
> say explicitly (the RK02 manual doesn't seem to cover configuration of the
> RX211).
>
> If that's not it, it may be time to break out the 'scope / logic analyzer.
> Luckily we do have the RX211 prints. I can whip you up a short program to try
> and read the CSR which you can 'toggle' in through ODT, if you've got a
> 'scope, not a LA. First thing to check would be to see if there are even
> cycles getting to the UNIBUS.
>
>      > 9. The next three slots have bus grant cards
>
> In the right connector, and in the right way around? (I know, I know, but
> at this point, we're grasping at the proverbial...)
>
>      > 13. I have tried a couple of other controllers - same result.
>
> As in, other kinds of boards on the UNIBUS? That's also interesting.
>
>      > 13. ... I'd like to get both monitor and boot proms back to standard.
>
> I suppose it's _possible_ there's an error in the non-standard PROMs that
> somehow buggers up the KTJ11.
>
> According to the "PDP-11/94 System User and Maintainence Guide"
> (EK-PDP94-MG-001, available online), pg. 5.49, the KTJ11 has some
> maintainence registers which can be set to cause it to do strange things (I'm
> just trying to absorb them all now).
>
> One thing to note: 'Diagnostic Mode' is set at power-on, and when set, it
> "the UNIBUS is disabled". So powering the machine on with it set to 'Halt'
> (so the boot isn't run), and using ODT to poke UNIBUS registers won't work.
> You'd have to let the startup run (which presumably leaves the UNIBUS turned
> on - or maybe not, something worth checking) and then halt it to use ODT.
>
> Anway, it would be interesting to see what the KTJ11's DCSR (at 17777730)
> contains.
>
> 	Noel
----------------------------------------------------------------------
RX211

         + ++ +
           +  + +

                 ++
         ++++    ++++

+= this end depressed
----------------------------------------------------------------------------

KTJ11's DCSR 17777730/000210

R