I just came across pictures on the LCM website about their SDS Sigma installation there.
On the pictures, one can see 10-platter disk packs in the corner and stored on the disk drives.
Did the LCM ever had these in operation, either for data retrieval or even demo purposes?
I know of the Jim Austin Computer museum where they fixed a CDC 9766 drive but it suffered
a head crash after a few hours according to their description which led to giving up the operation
of these drives.
Anyone on the list have a VT-180 a.k.a "Robin"? I got one for free a while back, but no disks. Wondering if anyone's in a position to make copies of their working disks and mail them to me -- I could have blanks sent, of course. I'm in the SF bay area.
As you know I've recently restored a couple of CP/M luggable
computers. I also have many other machines with floppy disk drives,
3", 3.5", 5.25" and 8"
The machine I connect to the internet with is a more modern laptop
runnng Windows 8.1. Essentially its only interfaces are USB ports.
I would like to be able to :
Download disk images (I assume in .IMD or .TD0 format) and write them
to real floppy disks to use in my old machnes
If possble, for the more common filesystems like MS-DOS or CP/M, be
able to work with these images on the modern PC at the file level. For
example, if I download a CP/M progam as a .COM file I'd like to be
able to put it into a disk image of a Philips P2000C disk, then
transfer that image to a real floppy and put it in a drive on the
I understand there are designed based on a modern microcontroller that
connecct to a USB port and a disk drive. Software on the PC translates
between the disk image and the accurately-timed pulses corresponding
to flux transitions on the disk. This unit links to a real disk drive,
you run the software and it reads/writes a real disk in said disk
Now... I can handle a 'scope. I can handle a logic analyser. I can
handle a soldering iron. I can handle an engineer's lathe. I can
rebuld and align floppy disk drives. I can program most 8-bit micros
along with PERQ microcode, PDP11 mahine code, etc BUT I don't have a
clue when it comes to modern PCs, modern microcontrollers or USB
So what I am asking is for people to describe what to do as in :
Buy this microcontroller board
Buy this blank PCB and solder the components given in the BOM to it.
Download this software and install it by doing this.
Connect a standard floppy drive to this connector
Run the software, specify the disk image file and sit back.
I'd rather not put a customer through the throes of sending a 10.5" reel
of tape written on a S/370 mainframe through international shipping.
Anyone in the Barcelona area with the equipment and ability to handle
reading this thing? Besides, I'm up to my ears in work.
I have an HP 2875B paper tape drive that I want to interface to. It has
a 50 pin block connector (using well under 1/2 the pins). The connector
manufacturer was Continental.
I have already discovered, the hard way, that it is not a winchester
connector - the pins on the 50 pin Winchester connector I just obtained
via ePay that otherwise fits are too small in diameter and won't make
contact. I *could* increase their diameter using solder - but -- yuck.
The other connectors of this sort I am familiar with that have the same
general overall size and pinout were made by AMP. Does any one know if
the AMP connectors and the Continental connectors would be compatible?
As some of you may be aware I am trying to find a fault in a Rainbow H7842
PSU. I am using Tony Duell's schematic from here
I have been testing the Control Module by using a bench PSU to supply 15VDC
to the input of the 7812 regulator (p2, PSU Sheet 1).
My diagnosis shows that the control module is shutting down the PWM (p6,
Control Module Sheet 2) because it is detecting an overcurrent in the -12V
side (E3d on Control Module sheet 1, although I have determined that it is
This seems to be because I measure a steady 0.6V on pin 6 of the transformer
(p4, PSU Sheet 3). I just can't imagine where it might be coming from as the
chopper won't be running. I had previously removed the transformer and there
are no shorts between the pin 5-pin 6 winding and any of the other pins on
the transformer. I checked all the DC outputs of the PSU when powering the
7812 from the bench, both on a working PSU and the non-working one. They are
all at zero except the -12V output on the non-working PSU, which is +0.6V.
But the voltage can't come out of nowhere.
I am stumped and would appreciate any suggestions.
On 5/28/23 09:17, Tony Duell wrote:
> I've come across the former and have the datasheets. From what I
> recall it was common to use it a control store sequencer and have
> microcode ROMs wider than the 8X300 needed, the extra bits were used
> to directly control hardware.
Power hog (well, it was bipolar) with a 3-bit opcode and a somewhat
strange programming model. You could usually spot one by the 50 pin
cerDIP and the external pass transistor. I think I still have a loose
one in my hellbox--and at least two in old systems.