test-drb September 2006

test-drb@ccmp.vtda.org

200 participants
374 discussions

by PLM3128＠aol.com

I am interested in the SN94281 do you still have and if so email me the price. Paul Moldenhauer email: _plm3128 at aol.com_ (mailto:plm3128 at aol.com) . thank you

17 years, 9 months

Need microprocessor trainer, oscilloscope advice?

by Billy.Pettit＠wdc.com

Dave McGuire wrote: On Sep 11, 2006, at 7:23 PM, Chuck Guzis wrote: >> Maybe, but there is one heck of a difference between working on an >> emulator and using (and modifying, interfacing, etc) the real >> hardware. >> And the OP wants to learn about hardware, I believe. > > Why not start with a "mostly on one chip" type of setup, say a Z8 or > 8051 > and work from there? There are plenty of small circuits published > using > them and, as the student's knowledge grows, other bits can be added on. This is a good idea. One can put together, using wire-wrap or point-to-point soldering, an 8752-based machine in an hour or two. Five chips, only one of which is a 40-pinner. Burn a copy of the well-known 8052AH-BASIC into it and you've got yourself quite a neat little machine. The BASIC interpreter has excellent I/O capability, interrupt support, and even floating-point math. If anyone wants to do this but lacks the stuff, I have 8752 chips and the means to program them. And the BASIC interpreter, of course. -Dave I agree with dave. But would add that some of the smaller PIC devices are also easy to work with and cheap. And there are several one line tutorials, as well as lots of supporting literature. Buy a couple of issues of Nuts and Volts to get started. And for a beginner, there is a nice book "Programmable Logic" that takes you through several of the basic I/O devices using simple logic interfaces, to demonstrate how easy they are to use and understand. I just found one on eBay for 99 cents, worth the price for getting started. Much more expensive, but Elektor did an outstanding beginners book on computers. Still available, but by time you import it, you're looking at $50 +. Billy

17 years, 9 months

Faulty keyboard on an Amstrad CPC 6128.

by austin＠ozpass.co.uk

A cheeky second post requesting assistance... I picked up an Amstrad CPC6128 today from an eBay auction. It is complete and came with a whole bunch of software. Unfortunately the keyboard has a few faulty keys and the 2? disk drive makes horrible grinding noises when I try to access a disk. Does anybody on the list have any experience of servicing these computers to give me some pointers before I tear it down? -Austin.

17 years, 9 months

Assistance required with an Acorn A3000, IDE Hard Disk

by austin＠ozpass.co.uk

Hello! Can anyone help me (off list, if necessary) with formatting an IDE hard disc, using a Castle Technologies IDE mini podule in an Acorn A3000 upgraded to RISCOS 3.11? Any advice gratefully received. TIA. Austin.

17 years, 9 months

13W3 adapters

by THX1138＠dakotacom.net

Hi, I need to make a 13W3 "extension cord" -- M-F *not* the M-M (or F-F, depending on how you look at it!) cables that Sun offered. I salvaged a sufficiently long video cable off of a <mumblemumble> Sun monitor -- so that gives me *one* end (and, one *sex*). The *other* sex is a bit more elusive (i.e. the gender that is present *on* the actual CPU). But, I found a <random> 13W3<->3BNC adapter in one of my goodie boxes. The 13W3 connector is "just right" (sex, form factor, mounting, etc.). So, the issue (and hence the question!) is: what sort of device might *want* this adapter (i.e. why should I *keep* it and not just salvage parts from it)? Note that the BNC pigtails are only a few inches long so I assume this would be attached to a 3BNC monitor and a "regular" Sun cable used to tether that to the CPU. Thanks! --don

17 years, 9 months

bad keys on terminals

by ajp166＠bellatlantic.net

> >Subject: Re: bad keys on terminals > From: "Dave Dunfield" <dave06a at dunfield.com> > Date: Tue, 12 Sep 2006 05:31:07 -0500 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > > >Dave > >BTW: I have similar vintage PETs with identical keyboards in >which the conductive rubber is fine ... anyone know what >conditions accelerate the deterioration of conductive rubber? > Ozone and other airborne contaminants. I have a old (30 years old) peice of black conductive foam that is stored in a large jar with cmos parts and some dessicant is in perfect condition. A peice >from the same block exposed to the air died (crumbled) over 15 years ago. I've also had several keyboards with foam backed pads (Cherry?) die on me. Same problem, either the glue dies or the foam. Allison

17 years, 9 months

CompuPro floppy controller differences

by ajp166＠bellatlantic.net

> >Subject: RE: CompuPro floppy controller differences > From: "Chuck Guzis" <cclist at sydex.com> > Date: Mon, 11 Sep 2006 09:19:56 -0700 > To: cctalk at classiccmp.org > >On 9/11/2006 at 8:02 AM Allison wrote: > >>The manual says two tracks on 8" and 3 tracks on 5.25 with track 00 being >>128 byte single density only. NOTE the manual says tracks not cylinders. > >All I can relate to you is the number of cylinders before the directory. >What CCS uses the extras for is anyone's guess. My 8" CCS sample is DS MFM >and reserves 4 cylinders for boot. > >Cheers, >Chuck Interesting, I have both SSSD, SSDD and DSDD media for my CCS system and none exceed 2 tracks for 8". I have no 5.25" so I cant speak for those. The DSDD media I have uses the first two tracks of side 2 for data and the organization if 2 tracks side 1 reserved and the next 75 tracks are data wrapping around to side 2 (77tracks). The software is as supplied from CCS to format that media. I wonder if CCS did a change or switch gears on their format? I do know it reads SSSD CP/M standard without issues. My CCS system is 2200 crate with 2501 backplane, 2810 Z80 cpu, 2710 4 port serial, 2704 bus terminator and 2422 FDC. The only non CCS part is the Compupro Ram16. It's a really nice system, well documented and very complete software when I got it. I was used for a development platform for another CP/M system. The most recent date code on anything in the crate is early 1981 so I figure it's from around then. I don't know if this is an early version or later. Allison

17 years, 9 months

Need microprocessor trainer, oscilloscope advice?

by reevejd＠mchsi.com

Hello All. I'm new to this list and would like some advice on learning the inner workings of vintage computers. I have some basic experience with electronics and some simple measurement tools (multimeter, logic probe). So far, I've repaired a couple of older machines (Kaypro's, Compaq portables) but this has amounted to swapping dead hard or floppy drives, replacing dead batteries, etc. So here are my questions: (1) Is there a "trainer" system good for learning about microcomputer design and operation, and (2) would an oscilloscope be useful for this purpose, and if so, what Mhz rating is needed to work on older machines? I've noticed the price is directly proportional to this number! Thanks, John R.

17 years, 9 months

Early/mid-1980s "Portable Computer" magazine?

by evan＠snarc.net

Does anyone have issues of "Portable Computer" magazine from the early-mid 1980s? - Evan

17 years, 9 months

weird C implementations?

by alexeyt＠freeshell.org

I was reading the C language spec (C99) and I got to wondring: are/were there C implementations that had no stack, or a rising stack? There's a falling stack in every implementation I've seen, but the spec doesn't require it. Alexey

17 years, 9 months

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test-drb September 2006