I have a CMD CQD-203/T (same board as the CQD-200, only with the S handle for the BA213) in my MicroVax 3900. This is a SCSI tape controller.
Is there any way to upgrade/convert this board into the /MT (disk/tape) version of the board? Is it just a simple EPROM replacement, or something more complicated/impossible?
In it's stock form, can this board work with a CDROM drive at all, or do I need the M or MT version for that?
Thanks!
-Ian
Jim Leonard writes:
> I was looking for a source of new diskettes and found Athana here:
> http://athana.com/html/diskette.html
>
> Anyone had experience with their product? I don't want to use these
> only to be wiping goo off of the inside of my floppy drives five years
> later...
I bought and recommended their 8" floppies and compatible RL02 packs
in the late 80's through mid-Lasnerian-90's. At the time I was
going through sizeable lots (500, 1000 at a shot.) Worked fine
back then... but it's been a long time!
Tim.
>
>Subject: powering up older machines - is it safe?
> From: "John F. Kuenzig" <jfk at kuenzigbooks.com>
> Date: Mon, 02 Jun 2008 18:21:02 -0400
> To: cctech at classiccmp.org
>
>Hi all - I'm new to the list, been lurking for a while. By way of
>introduction, back in the 80s I was a bonified software developer (wrote
>a mag tape locking device for an early version of UNIX back when there
>wasn't such a thing, did work in telecom test equipment and speech
>recognition for years) but these days I'm in the old/rare book business,
>technical books and all. I like old hardware, though don't have the
>storage space for much. When I was in high school I took apart a Friden
>computyper in my parents basement just to see what was in it. Still
>have the "core memory" board around here somewhere. I've tried to
>salvage manuals for old computers, component manufacturer technical
>books, and an IMSAI or two over the years. Still have 20 boxes of old
>components (everything from transistors, caps, resistors, etc to tubes)
>in the garage I've accumulated over the years when I'm buying old books
>from hobbyists - buried deep enough I don't even remember what's in them.
>
>Anyway, a friend asked me to try and sell a DEC Robin for him (he tells
>me it's a DEC VT180 with a separate drive unit that he tells me was only
>available to DEC employees), and my question is this:
;) have a few of them around.
>
>Is it safe to try and plug this machine in and try to power it up? I've
>seen various discussions about old capacitors dying, etc but I'm not
>sure if this machine is old enough to worry about. My plan was to try
>and power it up (my consignor also gave me some software with it, not
>sure if it's related or not yet), and see if it still ran ok, take some
>photos for the group (if anyone wants to see it) and my own records, and
>then try to sell it. It appears to be in good shape, in the original
>boxes, "monitor" in one box w/keyboard (looks to be a VT180), and a disc
>drive unit in the other. My consignor said it ran the last time he had
>it out many years ago. I've always enjoyed and preferred photographs of
>old machines with their startup screen displayed rather than a dark
>screen. Seems like they have more life with a live screen.
Generally yes in my exerience. The PS is a ASTEC switcher in the drive
and DEC in the tube/system case.
Customer could buy the second drive though when it was being sold it was
very expensive.
>Any pointers appreciated (on or off list) - what to do or check in what
>order would be great. Its been a long time since I blew up directional
>capacitors in lab...so long I don't even remember what they're called.
>Thanks in advance!<grin>
Generally every one I'd found powered up or was dead. The latter was
"it was dead when I got it" from the person before me and likely dead
>from the person before that.
Watch the VT100 monitor board. There is a cap that should be a higher
voltage part that fails in time taking parts. It's repairable if croaked
but people panic when they see chared board.
Allison
Framingham,MA exdigit.
>--
>Sincerely,
>
>John Kuenzig, Bookseller
>
>Kuenzig Books
>PO Box 452, Topsfield, MA 01983
>978-887-4053 9am-7pm Eastern Standard Time
>866-512-3053 tollfree 9am-7pm EST
>orders at kuenzigbooks.com (orders or inquiries)
>
>Important Books in Science, Technology and Speculative Fiction
>
>Secure ordering at http://www.kuenzigbooks.com
>Save time, money and earn other exclusive benefits.
>
>Members of:
>ABAA http://www.abaa.org
>MARIAB http://www.mariab.org
>ESA http://www.ephemerasociety.org
>
>Buying 18th-21st century books, manuscripts, ephemera,
>scientific instruments, artifacts, and related material
Subject: SuperBrain QD
past millennium."
Some of my systems are shown at www.8bit-matrix.net
<http://www.8bit-matrix.net/> . If you would like then do not hesitate to
have a look at you them there.
Superbrains and the related Intertube had terrible switching power
supplies. I would be very suspicious of the 5 volt line.
As an aside, the shop I worked in at the time had a picture of a
superbrain power supply on the wall, with the caption "component in
question is easily located by the charred area".
Les Hildenbrandt
Hi, this my first message here on the list and so I may say
"Hello, It is nice to be able to join so uncomplicated to this list and to
be able to exchange itself with you over the miraculous computers of the
past millennium."
Some of my systems are shown at www.8bit-matrix.net
<http://www.8bit-matrix.net/> . If you would like then do not hesitate to
have a look at you them there.
But now my actual problem.
I have a SuperBrain in my collection which has an electronically problem. So
I need the schematics for repair. I found some on the net but these are
really unreadable because they are scanned in very low resolution an
quality.
When I have gotten the system the keyboard decoder chip (KR3600-XXX) was
death. After I have installed a replacement the SB becomes running. After
few minutes this chip was broken again and the screen driver was possibly
gone with it.
I have some experience and equipment to figure out electronically problems
for repair. But without a readable schematics it would cost to much time.
So I'm full of hope that someone here supports me to getting back this
system to a proper and running state.
By the way, is there a replacement (self-made GAL-XXX eg.) or source to get
one original KR3600-XXX chip?
Regards
Juergen
I was just browsing the web for some advice about HP Pascal 3.25. You
were mentioning it while looking for HFS initialisation. Were you
successful?. I have Pascal 3.2 or BASIC 6.4. Both support HFS.
Did you find PASCAL 3.25 ???
Greetings. Jo
------------------------------------------------------------------------
Dr. Joachim B?hrmann-Schulz
Hardyweg 8
14055 Berlin
jobs at gmx.de
> This is not relevant to this particular rescue, but I know nothing
> about these systems and am curious. What type of OS and app software
> do machines like this run?
990's are 16 bit computers heavily influenced by the architecture of the pdp-11.
The main difference is the working registers were kept in memory, allowing very
fast context switches, at the expense of register access performance. Later machines
cached the register sets.
There was a small single-user floppy disk based os (for the 990/4 based on the TMS9900),
but the main OS was DX-10, which was replaced by DNOS on the 990/12 series.
Their primary use was in small buisiness, they had COBOL, FORTRAN, BASIC, and things
like rje, data base and forms management packages, and networking.
It seems they were widely used in inventory and parts management systems. The history
of the 990 says the system was originally developed as part of a hotel management system.
dave pitt's site (as well as bitsavers)
are good sources of information
http://www.cozx.com/~dpitts/ti990.html
Ade,
I think you mean the small transformer with 6 wires attached, this
transformer has 2 * 9VAC outputs and one AC-line input (230 or 110V depends
on region) This transformer is the supply for the regulator IC's in the PSU
the regulators are places on two small PCB's, on the large PCB there is a
rectifier (Greatz) witch you have to check.
If thats alright you have a reasonable change the PSU works after replacing
the transformer with a similar type 2 * 9VAC 3 to 5VA.
Rik
-----Oorspronkelijk bericht-----
Van: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
Namens Ade Vickers
Verzonden: woensdag 28 mei 2008 18:38
Aan: 'General Discussion: On-Topic and Off-Topic Posts'
Onderwerp: Transformer repairs
I was messing around with my SX-64 (which is on ePay as a working unit)
yesterday, having located some software & a joystick for it. I was going to
take a few photos of the new bits, etc.; for adding to the listing.
Then: *sharp snap/crack noise*, lights go out.
Aaaargh!
OK, first things first: There was no burning smell, and no (visible) magic
smoke released. The fuse wire in the glass fuse has been vapourised; the
mains fuse survived. I replaced the fuse, which has not since blown, but the
PSU is deader than a dead thing that's been dead for a week.
Some careful poking around with the multimeter (before the multimeter went
bang - ffs, I must have an anti-midas touch this week), then the
oscilliscope, reveals that a secondary transformer on the PSU has failed. I
presume it went dead short, then burnt itself + the fuse out simultaneously;
hence the reason the replacement fuse hasn't blown.
So, what I need to do now is replace the transformer, or get it repaired
somehow (ideally before Sunday, when the ePay auction runs out - or, to
definitely know it is unfixable in that timescale & thus cancel the
auction).
What I DO have, which might make a repair feasible, is a second SX-64; the
only difference is, this one has a US (117v) PSU. Obviously, the primary
transformer windings are going to be different, but is it possible/likely
that the secondary transformer will be the same? Going by the part nos. I'm
not terribly hopeful:
UK Part no: TDK 68-0409 B8326A
US Part No: TDK 68-0407 B8309A
A quick google on any of those numbers reveals nothing...
I don't have the means to create 117v 60hz power, so I can't test that way -
and even if I could, it turns out that the US PSU has taken a wallop at some
point, breaking the circuit board. :(
Hey ho... any help gratefully received.
TIA!
Best Regards,
Ade.
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