At 10:25 PM 5/5/99 -0700, Sellam Ismail wrote:
>
>Yeah, then I spray-painted it neon pink because I didn't like the original
>color. Core memory is cool.
No way. It wouldn't be Art until you made it into a dress, as a
commentary on the way technology has shaped our lives.
- John
I have an RL01 drive which isn't working correctly. I've opened up the back
end of the drive so I can see what is happening and what I see is this.
1. Drive starts to spin up, but it's obvious by looking at the spindle of
the drive motor, that the motor never reaches full speed.
2. After about 5 seconds, the drive slows some, and the heads attempt to
load.
3. The heads then chatter back and forth. They appear to move in about .25
inches and then retract.
4. This continues until I spin down the drive.
If I pull the pack out, and hold the switches closed manually, the motor
does reach full speed (although the heads never attempt to load).
If anyone has any suggestions as to what might be the problem, I really
apprecite some information.
Thanks,
Bill King
Hi Chuck,
-----Original Message-----
From: Chuck McManis <cmcmanis(a)mcmanis.com>
To: Discussion re-collecting of classic computers
<classiccmp(a)u.washington.edu>
Date: Wednesday, May 05, 1999 11:16 AM
Subject: More info RE: KA650 & uVAX
>Very cool, I actually picked up three UVAX38xx's in two of them were KA650
>cpus and in one was a KA655 CPU. All three have been "upgraded" to 32MB of
>third party memory. The "skunk" boxes were fairly trashed by the process of
>sparing them out. I'm guessing that they were part of a cluster.
Lucky day ;-))
> As for peripherals they all have TK70 tape drives, and the > associated
>controller,
starting to get envious ;-))
> one has a board pair M7164/M7165 connected by short cables
>across the top.
M7164/M7165 is the KDA50 SDI controller, not SCSI.
> And there is a drive hiding in one of them. (I've not
>identified it yet) they have what look like SCSI II connectors
> but a person
>suggested they might be DSSI connectors (which I know nothing about).
Could be SCSI, could be DSSI, tell us the type ...
>I'm going to see if I can bring one of the boxes to life, All are missing
>the panel that would have covered the card cage. If not I'll try to enhance
>the speed of my world box bases uVax II.
I would start with the ka655.
Not because she's faster, but the monitor program is better (sometimes the
ka650 have the same, but not always)
cheers & have fun,
emanuel
-From: Sellam Ismail <dastar(a)ncal.verio.com>
>
>Yes, I've got a complete system in my collection with the expansion
>chassis and manuals and such. I can try digging it out to make a copy of
>the relevant manuals and send them to you. Standard disclaimer on time
>applies :)
You are a veratible fount of goodies and generosity. What's in the
expansion chassis?
Thanks
- Mike
>> Flip flop should be easy too. This one looks rather like an ECL logic gate:
>>
>> +V DC
>> |
>> <
>> >
>> <
>> >
>> |
>> +--+--+
>> | |
>> (:) (:)
>> | |
>> A--+ +--B
>> | |
>> > >
>> < <
>> > >
>> < <
>> | |
>> GND GND
>>
>> Pull A to ground. Lefthand neon lights. Voltage on right hand neon too low
to
>> maintain discharge and it goes out. Same works for B - RH neon lights and
>> voltage at the common anode too low to maintain LH neon, which goes out.
>
> Nope! If left is not list then there is no current flow across the
> resistor. To ignite the left lamp a voltage (negative maybe 25V) would
> have to be applied at A. To extinguish left a voltage of +25(or more)
I see what you mean. (Careless of me!) A and B would definitely need pull-ups,
but I think it could work. The initial current when you apply the negative
pulse to one input should drop the voltage at the common anode sufficiently to
extinguish the other neon.
> volts would have to be applied. Generally this kind of logic is pulse
> coupled using transformers or capacitors. Note a bistable was done in the
> case mentioned with one Neon.
>
> Doing ascii logic from telnet seesion is far to slow for me to give a
> complete circuit.
Don't post a circuit yet - I want to think about the one-neon flipflop.
Theoretically possible, anyway - the two states are on and off (now why does
that sound vacuous?).
Philip.
Is this really off topic? It's really interesting anyway.
> Simple oscillator using NE-2:
>
> 90 VDC
> |
> >
> < 470K
> >
> <
> |
> +------+
> | |
> (:)NE2 _
> | - .1 uF 100V
> | |
> +------+
> |
> GND
Hmm. The capacitor charges through the resistor until the neon strikes. Since
the neon now draws more current than comes through the resistor, the capacitor
discharges through the neon until the neon extinguishes. Process repeats.
Neat. I suppose that if the resistor is too small, the neon doesn't extinguish,
but the capacitor merely discharges until it reaches the steady state voltage of
the neon at the current through the resistor.
I like it!
Flip flop should be easy too. This one looks rather like an ECL logic gate:
+V DC
|
<
>
<
>
|
+--+--+
| |
(:) (:)
| |
A--+ +--B
| |
> >
< <
> >
< <
| |
GND GND
Pull A to ground. Lefthand neon lights. Voltage on right hand neon too low to
maintain discharge and it goes out. Same works for B - RH neon lights and
voltage at the common anode too low to maintain LH neon, which goes out.
Don't know the component values though.
Outputs are also A and B. You may need pull-up resistors on them, depending on
what you're driving.
Fun.
Keep neons in light-tight containers, though! Are there circuits in which
optically coupled neons are useful?
Philip.
Hi all,
I would like to connect a Plessey disk drive to a PDP11 RK11-D controller.
The drive has a fixed platter and a removable platter, compatible to RK05 I
believe, and these numbers on it:
Plessey 3468-0231
PMDD/11B
700540-200217D
It has a 42 pin MRA 42 S mating connector, and same with a terminator. I
believe the 42 pin should be a Drive Bus, to be connected with standard
Unibus cable to controller slot 2A/2B.
Question: Would anyone have a maintenance manual for the Plessey drive
available ? Short of that, maybe the pinout of the connector, so that I can
make the cable ?
Of course, reverse engineering of the disk electronics should reveal the
pinout/RK11 compatibility, but having the docs just would save a lot of work
and be more reassuring !
Thanks and regards
John G. Zabolitzky
Ok, this one is puzzling me.
Everyone said "you need new memory for the KA650." Why?
The connectors appear to be identical, although the 650 supports ECC memory
(but does it require it?) Enquiring minds want to know!
--Chuck
