11 Jan
2019
11 Jan
'19
12:48 p.m.
On 1/11/19 3:34 PM, Jerry Weiss wrote:
On 1/11/19 11:28 AM, Bill Gunshannon via cctalk
wrote:
Nothing but CPU and memory at this point. And there will never be
drives as I will be using SCSI and 6 of them sit in a box of their
own just waiting for the PDP-11 to wake up and smell the coffee.
Well, it has been so long since I had to put
together an
entire system I forgot what fun it can be.
With almost documentation I was able to configure 4 1meg
memory modules and I tested them all in my 11/23+ box.
KDJ11-B with 4 different (but similar) memory cards.
"MAP" option of the KDJ11 shows 4 meg (minus the I/O
Page) and all the right CSR's for the first four blocks.
Really wanted to make this a deskside so I moved the
cards to a MicroPDP box (Yes, I have a coule of the
deskside pedestals). Power on, Memory CSR error.
Move then back to the 11/23+ works fine. If I only
put the first three in the MicroPDP box it works.
But as soon as I try to put in a fourth module I
get the memory CSR error. Tried different cards
(although working in the 11/23+ box would make me
think it is not a problem with the card) no help.
Anybody care to take a stab at what might be causing
this problem?
1) You might want to check your power supply loading.?? You have a
lot
of memory of chips to feed. ? The H7864 output at +5V is 36 amps.
Between the KDJ11-B and 4 memory boards you may be using between 20-25
amps. Add a? disk controller, disk drive and any other Q-bus devices
might bring you close to the limits for either +5V or +12V from an aging
supply.
2) Are the CSR addresses between 17772100-06?? Have you tried to move
them above this range just to see if the behavior changes?
CSR's are right. As I said, the combo worked until I moved it
to a different backplane. I think Allison has the idea. I am
going to go back and look into bus grants. But I would have
thought they would be alright as the likelihood of these being
in a serpentine A-B box seems much to likely for them to not
be capable of it.
bill