Pat said:
> On Thursday 13 September 2007, J Blaser wrote:
>> Lastly, be cautious around the head actuator. The heads and the
>> spindle (plate) are carefully aligned, and I wouldn't remove or
>> adjust either of these. Unless, that is, you have the printsets and
>> proper tools (which I don't).
> Actually, the RL02/RL01 is an embedded servo drive, so "head alignment"
> generally isn't critical, at least like it is with the RK0n drives.
Yes, excellent point.
I was thinking more in terms of the possibility of getting the
horizontal forward/backward 'tilt' a little bit off, that is,
when the heads are on the outer tracks versus when the heads
are extended to the inner tracks, is the flying height the same?
Also, I might add that I removed the platter brushes from
three of my RL01s last year, based on commentary here on the list
and other groups. I'm not sure if RL02s were ever produced with
brushes, but if so, it might be worth checking. The three RL02s
that I have in another PDP-11/23 PLUS never had them.
- Jared
Josh Dersch said:
> Just picked up an RL02 for a song. It's a bit beat up looking, but it
> seems pretty clean inside, so far.
Glad it was for a song, and not for money! ;)
> It's kind of a moot point at the moment, since I have no disk packs,
> cabling, or interface boards (so I can't use the darned thing until I
> complete a scavenger hunt...) but I'm wondering what I should check out
> on this machine before I power it on & (eventually) start using it...
Having been through four RL01 in the past 12 months, I might have
something to offer. By no means am I the RL0x drive expert, but
here goes...
For me, the very first thing that is done (after the exterior cleaning,
of course) is the reform the capacitors. These RL0x drives have
two capacitors of interest: a 66,000 uF 30V, and a 22,000 uF 40V.
I suppose it happens all the time, but I don't like to power up
anything until I've removed the capacitors and put them through
the reform(ul?)ation regime.
Don't want to be too pedantic, but here are the steps I took:
- remove the service cover (4 screws), then cartridge door/cover.
- clean the interior as required (vacuum, Windex)
- lift the DC servo PCB, make a note of the connections, disconnect
the power connector
- carefully lift and rotate the box above the head actuator to get
access underneath
- disconnect gounding wires to lugs on I/O PCB in service cover, and
the inside of the rear chassis. You may find another wire to the head
actuator 'box', too.
- remove the four screws on the rear panel to remove the power
supply (the whole rear chassis panel). Be careful as you loosen
screws since the rear panel is top heavy and my tilt out when you
least expect it.
- Now you have full access to the PS and can disconnect and reform
the caps.
While the caps are reforming, here are a few other things you should
consider:
- take a vacuum hose to the inside of the cabinet and then wipe
(windex for me) every surface.
- remove the front bezel/cover to get access to the switch assembly.
- your coarse filter is probably falling apart as mine were. I replaced
the filter with some new-fangled Dupont furnace filter (mumble the
name) which has three components: a rigid plastic stabilizing grid,
a very course filter, and a fine (10 micron) filter mesh. I cut a
rectangle of the fine mesh to fit and held it in place with the
stabilizing grid, alos cut to fit. It works very, very well.
- When the caps are done, put it all back together, and enjoy! :)
I have a couple of drives the sort of quietly squeal a bit when first
spun up, but I never found any information on lubrication, etc., and
they quiet up after about 30 seconds, so I don't worry too much.
Lastly, be cautious around the head actuator. The heads and the
spindle (plate) are carefully aligned, and I wouldn't remove or adjust
either of these. Unless, that is, you have the printsets and proper
tools (which I don't).
Good luck!
- Jared
Hi,
> PE (Practical Electorncc) 'CHAMP' system, in 1977 or so. It
>was built on stribboard (and IC postion layouts were given, but
>you had to work out where to run the wires from the shcematic).
>As was the assembly listing of the monitor ROM.
A couple of years later they produced the "System 68", a 6800 based machine
constructed on Eurocard sized PCBs (though using an edge connector rather
than a DIN-whatever connector).
IIRC circuit diagrams and PCB layouts were provided, along with a full
listing of the system monitor program. You could even buy ready made PCBs
(and kits of parts?) from a little company called "Newbury Data"....they
actually had an office a couple of miles down the road from here at the
time.
Not sure whether ETI published the PCB layout for the "Triton" (I'm pretty
sure they didn't, it was a fairly large, through hole plated PCB), but they
sure publisged the schematics and monitor listings.
Then there was the UK101.... :-)
TTFN - Pete.
>
>Subject: EPROM Question
> From: "Zane H. Healy" <healyzh at aracnet.com>
> Date: Fri, 14 Sep 2007 12:26:46 -0700 (PDT)
> To: cctalk at classiccmp.org
>
>I've been trying to google up an answer, but have had no luck. What is the
>difference between a 27256 and a 27C256 EPROM? Can a 27C256 EPROM be
>substituted for a 27256?
>
>Zane
Yes, gernerally. If your programming it limit Vpp to 12.5V otherwise
the same.
Allison
After putting it off for many, many years, I've decided to break down
and do it. I'm in the market for a device to read and program
EPROM's such as would be found in DEC or Commodore 64 hardware.
Something that can also handle other chips (Such as PAL's) that I'd
find in DEC or Commodore hardware would be nice.
I'm looking for something that is either dirt cheap, or that I can build.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
I'm playing with a Computer Logics PCTD-16 Pertec tape drive
interface board and my Fujitsu M2444AC drive. I can perform tape
motion commands just fine, but data commands begin and do not seem to
complete. I've checked that IDBY (J2 38 or W) comes ready at the end
of a read or write, so my next guess is that I've got the cable wire
wrong somewhow. My reference has this pin connected to pin 24 on the
DC62 connector to the controller.
Here's what I'm using:
http://www.sydex.com/overcbl.html
Have I missed something? Can anyone double-check this?
Thanks,
Chuck
>
>Subject: Re: 8-bitters and multi-whatever
> From: "Roy J. Tellason" <rtellason at verizon.net>
> Date: Thu, 13 Sep 2007 17:33:33 -0400
> To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org>
>
>On Wednesday 12 September 2007 07:43, Allison wrote:
>> Mine started when I needed to get stuff from the various CP/M systems
>> that even when they had disks were incompatable hard sector to soft
>> or 8 and 5.25. I started with serial peer to peer as in pipmodem and
>> similar.
>
>Pipmodem? That's a new one on me, though the name is pretty suggestive.
PIP has an area that the user can modify as an aux device outside
those in the bios (or part of the bios). Try doing a google on it.
>
>> Later I did a two system resource sharing that grew to allow up to a
>> potential 256 systems. In '82 the whole thing peaked with a multiprocessor
>> S100 crate with intercommunications via pooled memory.
>
>How was that handled in the hardware, particularly with regard to contention
>for access? I vaguely recall running across some multiport memory chips,
>but their capacity wasn't anywhere near what was currently in use that didn't
>have that feature.
Real simple the pooled memory was often just a block of ram in common space
and each cpu had it's comminications area and a doorbell register to signal
that it needs to check it's pool. The protocal was A writes to Bs com area,
A hits Bs doorbell, A waits for doorbell and goes back to check As comm area.
Since S100 bus arbitration allowed only one bus master and none of the areas
overlapped it was very robust. It relied on bus mastering, a clear protocal
and the "doobell register" to do attention requested signaling and keeps the
message block from read part way while being written. By assigning buffers
that do not overlap it made sure one cpu didn't corrupt anthers message.
However for systems without bus master arbitation other schemes existed too.
S100 IEE696 had bus master arbitration and Compupro and others used that
scheme. It was by no means the only way.
For example Ampro (AmproLB+) used the SCSI/sasi bus for it's communications
between CPUs.
Allison
Some ultra-rare laptops I picked up recently:
- Teleram T-3000 with external disk drive and manual (1982)
- MicroOffice RoadRunner (1982)
- Dulmont Magnum with manual (1983)
What'd I spend on these? Don't ask, or my bank account might revolt
against me. :)
My collection of early laptops now includes, but is not limited to:
1982:
- Grid Compass 1101
- Teleram T-3000
- MicroOffice RoadRunner
- Epson HX-20
- Grundy NewBrain model AD
1983:
- Kyocera Kyotronic KC-85
- Gavilan (eponymous.)
- Dulmont Magnum
- Sharp PC-5000
I'm currently borrowing a Casio FP-200 (1982) from a friend, and I own a
Convergent Workslate (1982/3), but I can't decide if those are large
handhelds or small laptops. It is a dilemma!
Still looking to acquire a Sord IS-11 and a Xerox 1800 "Sunrise".
Hello,
I saw an old post by you where you were looking for Hal Hardenbergh. Did you ever find
anything out? My name is James Shaker. I worked for him for about 5 years during the
DTACK Grounded era.
James
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