RQDX3 problems

Stacy Minkin stacy at asia.uznet.net
Mon Mar 16 17:00:16 AEST 1998


Hi pdp people!

Few days ago I wrote about my hardware problems and asked
for hardware guru. Now I've solved some of them -
I checked my backplane and it was 18-bits I wired 
insufficient A19-A21 signals and my CPU acessed memory and
now it runs ok. But! I still do not know what happens to
my RQDX3! 
I know that this question has little relation to UNIX 
and apologize for that.

I hardly suspect circuitry fault but may be some
other reasons. It looks like this:
-My RQDX3 is now connected to simple 5-inch floppy drive
when I power up the machine I see no activity on ANY
pin of RQDX3 to RQDX SIG. DIST. 50-pin connector! I mean 
there is no triggering signals hence my floppy 
also does nothing. When I try to execute bootstrap or
simply debug RQDX3 registers from console it looks like this:

RESET
CLR @#1772150
<checking 1772152 - it holds 5500 - kinda normal>
MOV #100000,@#1772152	; controller passes INIT step 1
			; no ints enabled, no vector specified,
			; UDA OWN bit set. Rings are zero length
<checking 1772152 - it holds 10000 - step one passed>
MOV #xxxxxx,@#1772152	; controller passes INIT step 2 
			; specifying low address bits
<checking 1772152 - it holds 20000 or something alike - 
		    no error bit is set - I'm sure- step2 passed>
MOV #0,@#1772152	; controller passes INIT step 3 - specifying
			; high address bits>
<here we can wait for eternity!!!!!!!! Step 3 will never complete>

Does anybody know what does it mean? I also have TMSCP TQK70
controller but no tape drive for it. When I try to run it there 
is absolutely similar situation - I think this happens each time 
[T]MSCP controller tries to powerup without any drives connected to it.
So I'm looking for help from somebody who can give a hint
about which signal should i check to assertain in absence of hardware fault.
I have no drawings for RQDX3 neither user's guide. It can even be caused
by wrong setting of switches/jumpers - I dont know.


Stacy.

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