test-drb October 2002

test-drb@ccmp.vtda.org

261 participants
654 discussions

IBM 5120 (was Re: My First S-100 System)

by vassilip＠dsl.cis.upenn.edu

"Scarletdown" <SecretaryBird(a)SoftHome.net> wrote: > I might just build a very minimalist 386 or 486 system from spare parts > I have lying about here, set it up with FreeDOS or MINIX, and make that > the console. [...] Actually the easiest way to build a 386-based terminal is with MSDOS (or DRDOS) and kermit. Kermit supports most serial cards and even some ethernet cards (so you can telnet over TCP/IP). There is even DOS-based software for mouse support (so you can cut & paste text). Kermit or DOS can take care of most input and output conversions so you can talk to almost any system that support telnet or async serial. BTW since most IDE disk have a spin down feature, you can spin down the disk just after you load kermit, so you don't even have to listen to the hard disk. Many systems of that era didn't have PSU fans, so spinning down the disk made the system totally quiet. **vp

22 years, 2 months

Rise and fall of MS-DOS floppy FORMAT program

by healyzh＠aracnet.com

> Sounds like motivation to keep a bootable DOS5 system around, with both > 3.5" and 5.25" drives.... And don't forget to have an ethernet card, and either a copy of PCTCP, or anotherbootable OS on the system that has a TCP stack. One of these days I'm going to build such a system. I've managed to collect all the parts, and even a nice small PC, I just haven't found the time (or really a place to put it). Zane

22 years, 2 months

Rise and fall of MS-DOS floppy FORMAT program

by Fred.van.Kempen＠microwalt.nl

> What's to know? Still.. > How available is it? Dunno. Technically, I shouldn't have it, right? Then again, MS dropped DOS quite a while ago, so... pfff... Fair Use for retro-hackers ? :) --f

22 years, 2 months

Rise and fall of MS-DOS floppy FORMAT program

by Fred.van.Kempen＠microwalt.nl

> This may have been the very first (for me at least) of the by now > innumerable MS Gotchas Dunno about MS-DOS V6.22; I'll look it up in the format.exe source.. (yes, we have the source, and no, we're not gonna fix it ;-) --fred

22 years, 2 months

Favorite terminal

by ken＠seefried.com

> >Isn't this the commercial version of the Blit? > Yup. > >Does anybody actually have one? > Nope. I last had my hands on one circa 1988. Never seen one on eBay... > >"Ken Seefried" <ken(a)seefried.com> wrote: > My most favorite was the AT&T 5620 with a host running layers. >

22 years, 2 months

Epson HX-20 repair details

by M.Clemence＠exeter.ac.uk

Hi there, I have a two Epson HX20's (which we use in our reasearch lab - yes still - to control some equipment) one of which has sufferred a failure of the power supply on the main CPU board (details below) and I need to get hold of a schematic if one exists. I beleive that Epson produced a repair guide - does any one know where I might be able to source this information. I have had a plough through the archives to this list and there are some very helpful people out there and maybe if anyone has some experience with this machine and can give me pointers - the following might help ... The batteries and external adaptor are good (new) charging correctly and delivering 4.8 V. However, the power switch has no effect (no LCD, no beeping) The main power rails seem to be off - there is 4.8 v at one test point 0 at another an 2.8v scattered around the board. There seems to be no 17 V which I beleive is needed for the LCD. The previous owner reported a burning smell so component failure is suspected, but no obvious signs on the transistors. A previous writor in the archive (Tony Duell) suggests that a volatge should be present on the collector of Q8, this is absent. Thanks in advance Yours Matthew Clemence

22 years, 2 months

Parts for Teletype ASR35 needed

by stefan＠softhome.net

Hi, I have here a half working Teletype ASR35. I am missing some parts, namely the plastic hood, manuals and some lightbulbs. Also the ASR35 isn't working properly, I am missing half of the keyboard sorta speak, you can type uptil the letter H or so and then if you continue it starts with the A again. So any help with that is also welcome. Thanks!! Stefan.

22 years, 2 months

HP 9915A (industrial version of HP 85A)

by gil＠vauxelectronics.com

Hi Joe: I subscribed and posted to cctech, but found your response in the cctalk archive. This list is new to me -- do you think I should I subscribe to cctalk instead of cctech? >>>I have three or four 9915s and a keyboard... I don't know what the difference is between an A and a B model... I did make a schematic of my keyboard but I haven't seen it in a while... >>> As I understand it, the 9915A is compatible with the HP-85 (aka HP-85A), while the 9915B is an 85B. IIRC, the 85B has built-in mass-storage and i/o roms, and more ramdisk memory than the 85A. I'd sure appreciate any keyboard info you may run across -- I could program a little pic to convert a serial keyboard. If this keyboard is used with other HP machines, other folks might find an adapter handy too. >>>You need to use the HP composite monitors. IIRC the PN is 82912 and 82913. These are used on the HP 86 and commonly used on the 9000 220 (aka 9920) and are pretty common. >>> >>>There were software developement kits available that let you write programs in assembler and burn them into EPROMs that plugged into a HP-85 type plug-in cartridges (called a Hybrid ROM or something like that) or directly into the 9915. The EPROMs that are in it are probably Matrix and/or I/O ROM IIRC. That seems to be standard in the 9915s that I'm aware of. >>> Yes, I have a programmable-rom-module and assembler rom (but have not tried them yet). A buddy of mine has managed to read 85 roms and burn them into eproms for the prog-rom-module. The original 85 roms seem to be special, and cannot be simply duplicated. I opened up a rom, hoping to find a standard package, but found a chip covered in a blob of epoxy, attached directly to a small board. I opened the rom drawer card, and found that all six sockets are wired in parallel (no individual enable lines to each). Then I looked at the signals connected to the rom card connector (using the serial manual's connector pinout as a reference). The roms have +12V, +6V, and -5V power. There is an 8-bit bi-directional bus, and four non-overlapping 12V clock signals. There is a "load-memory-address" line, a "power-on" line, "read" and "read-control" lines, and even a "write" line (I don't know why write is available on a rom). This all leads me to believe the roms are pretty specialized. Since there are no lines to enable a specific rom socket, I think the 85 must poll for roms using fixed address ranges or something -- this implies that the roms contain address qualification circuitry of some sort. I'm just speculating, but it would make the roms very difficult to duplicate, since this is not a standard address-bus/data-bus (or even a typical multiplexed addr/data bus). Thanks for the info Joe, gil ;----------------------------------------------------------- ; vaux electronics, inc. 480-354-5556 ; http://www.vauxelectronics.com (fax: 480-354-5558) ;-----------------------------------------------------------

22 years, 2 months

Computer Garage - 'Garage Sale' update

by jimw＠agora.rdrop.com

Quick note: some new items in the 'Garage Sale'! http://www.rdrop.com/~jimw/Gsale -jim --- jimw(a)agora.rdrop.com The Computer Garage - http://www.rdrop.com/~jimw

22 years, 2 months

Model 100

by Econsulting＠earthlink.net

Is your Radio Shack Model 100 still for sale? How much?

22 years, 2 months

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test-drb October 2002