test-drb

test-drb@ccmp.vtda.org

101090 discussions

Stupid AC wiring question (220-ish Volts...)

by derschjo＠gmail.com

I picked up a "large" machine* (for certain definitions of large) that's currently configured for 220-240V; my house at the moment lacks 220V receptacles. I was already planning to get an electrician out here to put in some beefier wiring at some point (I have a couple of machines that draw 15-20A off of 120V that I'd like to be able to run) but I wasn't yet planning on doing 220V unless I have to. (It looks like in theory it's possible to reconfigure the supply for 120V but I lack the docs to do so with any level of confidence...) I don't know if this machine works, and I'd rather not invest in 220V wiring quite yet unless it does. And, let's face it, I'm spoiled and I demand instant gratification and I'd like to know as soon as possible if this machine is a basket case or not. So: since all this stuff is in the basement, I'm just about 15 feet away from the dryer, which at first glance runs off an outlet that meets my needs. I even have a NEMA 10-30p plug here that I could wire up to the existing power cable for the computer. But looking into it I have doubts that it's actually that simple; in particular since this house was built well before 1996 and so the outlet is not grounded; there's a neutral lug and two hot lugs (I assume two 120V A/C lines out of phase?) and I'm guessing that might not sit well with the power supply in this computer. But then, I'm a rank amateur when it comes to house wiring and A/C and power supplies and all of that so I thought I'd ask the cctalk collective whether this can be made to work or if I should simply wait for a professional to take care of it... Thanks as always, Josh * An AMT DAP 610, if you must ask. It's an array processor from the late 80s, with 64x64 1-bit processors. If the machine doesn't run I'm pretty much SOL for spare parts, schematics, service manuals, or anything beyond customer-level documentation (which I've recently scanned, btw, if anyone's curious...)

11 years, 6 months

Did Dr. Marc Dean Design the IBM PC or was it Lewis Eggebrecht

by christian_liendo＠yahoo.com

Ok.. So Engadget wrote this article claiming Dr. Mark Dean was chief engineer of the 12-person team that designed the original IBM PC in the early '80s http://www.engadget.com/2015/02/06/mark-dean-pc-pioneer/ I had always thought it was Lewis Eggebrecht. I know there were three teams and one of them won and it was Eggebrecht's team. Did Dr. Marc Dean work on Eggebrecht's team or did he run one of the other ones?

11 years, 6 months

Fry's expansion? was: RE: Radio Shack

by tiggerlasv＠aim.com

On Fri Feb 6 15:09:42 CST 2015, geneb geneb at deltasoft.com wrote: > They're in Renton, WA as well. Now if they'd just keep the parts pegs filled... Yeah, that's been on ongoing issue for Fry's at all of their locations. I've been to Fry's in San Diego, Las Vegas, both Phoenix locations, Wilsonville, and of course the one closest to me in Renton. Great place if you need PC components; they have a lot of odd/unusual items that you might ordinarily only find on-line, or at PC swap-meets. You'll find some killer deals there as well. Several years ago, they were clearing out some 18-gig SCSI Cheetahs. I picked up 4 of them for $20 each. However, as mentioned by Gene, they are frequently out-of-stock on a lot of their electronic components. . . whether it is an obscure item or commonly-used components. I can never rely on finding the right value cap or resistor on their shelf. Another quirk that they have is product placement and pricing. You might find an audio adapter or cable by one manufacturer in the components section at one price, and in the audio section by a different manufacturer, at a significantly different price. I've also noticed that (at least in Renton) that their selection of generic cables has decreased, in favor of expensive brands like Monster or Belkin. Nowadays, I don't even mess with Fry's for A/V or computer cables -- I go straight to MonoPrice.com T

11 years, 6 months

Fry's expansion? was: RE: Radio Shack

by cclist＠sydex.com

On 02/06/2015 11:58 AM, Bill Sudbrink wrote: > Marc Verdiell wrote: >> Here in the Valley, Fry's Electronics took over, and then made it so >> much better. Fry's is where you stop at lunch time, for amateur or >> professional stuff alike, and get an instant replacement for your >> fried LM7805. > > A few years ago, there was a rumor that Fry's was going to expand out > of the Valley. I wonder whether that might happen now that RS is > on its way out. Where have you been the last few years? http://www.frys.com/ac/storeinfo/storelocator --Chuck

11 years, 6 months

Fry's expansion? was: RE: Radio Shack

by rickb＠bensene.com

There is a Fry's in Wilsonville, Oregon -- They've already expanded out of "the valley". -Rick > -----Original Message----- > From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Bill > Sudbrink > Sent: Friday, February 06, 2015 11:59 AM > To: 'General Discussion: On-Topic and Off-Topic Posts' > Subject: Fry's expansion? was: RE: Radio Shack > > Marc Verdiell wrote: > > Here in the Valley, Fry's Electronics took over, and then made it so > > much better. Fry's is where you stop at lunch time, for amateur or > > professional stuff alike, and get an instant replacement for your > > fried LM7805. > > A few years ago, there was a rumor that Fry's was going to expand out of the > Valley. I wonder whether that might happen now that RS is on its way out. > > Bill S.

11 years, 6 months

It's time to restore the 11/45 - progress!

by jnc＠mercury.lcs.mit.edu

> From: Jacob Ritorto > I guess this crowbar thing tripping, is just its way of trying to > protect the rest of the system from overcurrent, right? Over-voltage. Voltage != current. :-) > And the dried up cap is one thing what could make it think there was an > overcurrent situation, correct? I think the concept is that the cap could have shorted out, thereby causing a too-high voltage to pass through it - or something like that! :-) In general, cause the circuit to mis-behave. > I don't know that I'm going to understand how to read the schematic. I struggle with the analog circuits too. Just keep plugging away at it, each will slowly start to make sense. (Not the most complicated/sophisticated aspects, but if you understand a lot of what's going on, I'm sure someone here can help on the tricky bits.) > Also going to try to find a manual that describes the power supply. DEC's maintainence/technical manuals are very good indeed for explaining how the analog circuits work - especially for those of us who can't just glance at a schematic and instantly, intuitively understand how the whole thing works. For me, reading them is really pretty much a must before trying to debug/repair analog stuff. > But what is a valid test once I find it? This is where you need test instruments; an ESR meter (although that's not a universal solvent), a capacitance meter, etc, etc. (Also an ohmmeter, to check for shorted caps.) > I don't have much electronics gear here. If you seriously expect to repair something like an 11/45, at a _minimum_ you need a decent 'scope. Don't even _try_ thinking you can do it without one. Fuhgeddaboutit. I like Tektronix 465's - they are common on eBay, and if you're patient, you can get one for $60-70. They are also a 'scope much used on these machines BITD. (We did.) Past that? Well, there are things that are nice to have (e.g. a de-soldering station), but you can often work around them (e.g. a pair of dikes and a solder sucker). A logic analyser would be nice, and I keep meaning to get one, but I haven't, yet, so they aren't essential. (Although for _some_ faults, a 'scope just doesn't cut it. If you can write a loop, fine. If not... time for a logic analyzer.) I'm trying to think what else is absolutely essential, past the 'scope (and the meter - you ought to buy your own, they aren't that much). Nothing comes to mind immediately - perhaps someone else here can add to the list. Noel

11 years, 6 months

Remember Coherent?

by lproven＠gmail.com

I could never afford it & figured I wouldn't understand it if I did. But it sounded really cool. Well, as of last month, it's now FOSS. http://www.nesssoftware.com/home/mwc/source.php -- Liam Proven ? Profile: http://lproven.livejournal.com/profile Email: lproven at cix.co.uk ? GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lproven at hotmail.com ? Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) ? +420 702 829 053 (?R)

11 years, 6 months

DEC MKA11 and/or M8261/M8163

by pbirkel＠gmail.com

I don't understand the role of the M8162 "Port MUX A module" and M8163 "Port MUX B module" that the field-guide claims to be part of the MK11. They aren't part of the MK11 as far as any documentation that I've read regarding it. At least the M8162 has a pair of 20ma-style SLU connectors on it, but no UARTs that I can see. Do these modules really belong to the MKA11, rather than the MK11? Or to something else entirely? Is the MKA11 (which I can't find documented online) a revised MK11? The field-guide seems to imply this given its entry for the M8164 which basically reads like this: M8158 MK11 U Address buffer module M8159 MK11 U Data buffer module M8160 MK11 U Control A module M8161 MK11 U Control B module M8162 MK11 U Port MUX A module M8163 MK11 U Port MUX B module M8164 MK11/MKA11 U Data buffer module (Replaces M8159) It seems to me that something is incorrect in the field-guide, but none of my researches have identified where the error is and what the right answer(s) might be. Anyone here have any experience/knowledge with/of the MKA11 and/or the M8261/M8163? Thank you, paul

11 years, 6 months

ISA ( PC ) 8" floppy disk CONTROLLER ???

by gerardcjat＠free.fr

Thanks Shaun !! If you find the interface card and associated documentation, I would be interested. Please, let me know My philosophy : DBIT adapter is probably a very good product ..... but If I can stand with ** genuine ** "old stuff", I would love it . --- L'absence de virus dans ce courrier ?lectronique a ?t? v?rifi?e par le logiciel antivirus Avast. http://www.avast.com

11 years, 6 months

It's time to restore the 11/45.

by jnc＠mercury.lcs.mit.edu

> From: Jacob Ritorto > Can anyone understand and explain the unibus a / unibus b concept? I've never personally worked on a machine with them separate, but the picture on pg. 15 of the 11/45 Processor Handbook (1971 edition), and accompanying text, should make what's going on pretty clear. You have the 'normal' UNIBUS ("UNIBUS 1" they call it), controlled by the 11/45 CPU, on which regular memory, devices, etc live. The CPU also has access, via a special path (I guess this was later named "FASTBUS"?), to two _separate_ banks of high-speed memory. Those memories are _each_ dual ported; one port to the CPU's direct path, the other to a second UNIBUS, ("UNIBUS 2"). So something on UNIBUS 2 could be talking to one bank of high-speed memory while the 11/45 CPU talks to the other bank - while at the same time, a DMA device on UNIBUS 1 could be talking to memory on UNIBUS 1. I.e. three separate memory transfers all going on _completely_ simultaneously. UNIBUS 2 does not have a 'bus master' - one has to be provided by plugging some PDP-11 into it. One can either plug another PDP-11 into UNIBUS 2 (forming a primitive multi-processor, one in which the two machines share access to the high-speed memory on the 11/45); or one can 'jumper' the two UNIBI (is that the plural?) in the 11/45 together, at which point DMA devices on UNIBUS 1 can do DMA into the high-speed memories (which they do not have access to, if the two are separate). The way grants, etc, work is pretty simple. (You can skip this part if you don't care about the really gory details. :-) UNIBUS connectors include BGn and NPG - in at one end of the cable/jumper, out at the other. So that short section of UNIBUS 2 (it's actually just a chunk of the 11/45's main backplane) can either have: - a pair of UNIBUS cables (one in, one out) to make it part of some other machine's UNIBUS; - one UNIBUS cables (in), and a terminator at the other end, to make it the last thing on that machine's UNIBUS; - a UNIBUS jumpers (in) to make it part of the 11/45's UNIBUS, with the 'out' UNIBUS connector on UNIBUS 2 leading to the rest of the 11/45's UNIBUS If you don't jumper UNIBI 1 and 2 together, the 'UNIBUS out' cable to the rest of the 11/45's UNIBUS is plugged straight into the CPU's 'UNIBUS out' slot (i.e. where the jumper would have plugged in if the two UNIBI were united). > Should I eliminate all this fancy bipolar and core memory and just use > an m7891? For debugging, yes; simplest is always best. But if you have the fancy bipolar or MOS (not core; the fast memory path only supports the first two), don't pitch it, it's probably rare and unusual; and once you have the machine running, you may want to play with getting it running. > If I did, would it be on the fastbus, unibus a or unibus b and would it > even matter? Has to be on UNIBUS 1. (UNIBUS 2 becomes part of UNIBUS 1 if the two segments are jumpered together.) Noel

11 years, 6 months

Jump to page:

2026

2025

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

1999

1998

1997

test-drb