test-drb February 2010

test-drb@ccmp.vtda.org

175 participants
221 discussions

by root＠parse.com

I have now completed the detailed inventory of the museum. Please see: www.pdp12.org for the extensive list. I will be entertaining offers until Sunday, February the 28th for the entire museum in one lot. Contact me for details at rkrten at gmail.com. I will make a decision Monday, March 1st. Cheers, -RK -- Robert Krten

15 years, 2 months

cctalk Digest, Vol 78, Issue 47

by dm561＠torfree.net

From: Ethan Dicks <ethan.dicks at gmail.com> Subject: Re: Solderless breadboarding (and 68010 vs 68000) To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> <snip> >> [1] The local pound shop (a similar concept to dollar stores) was selling >> a camping lamp with 24 white LEDs for a pound. >I'd buy that for a pound! (and repurpose it, as you have). -ethan --------- Check your local Dollar store; I just happen to have a couple of those 24 LED lamps in front of me at this very moment that cost $1.50 ea. (modding and putting them under the kitchen cabinets). Lots of neat stuff in Dollar stores; amazing that they can sell a solar powered/battery backed scientific calculator for $1.00 these days, esp. considering shipping and several middlemen also making a profit... Button cells 5/$1, $7 ea. at the Shack... etc.

15 years, 2 months

Cross country hauling

by wdonzelli＠gmail.com

Again for 2010, I am crossing the country and am offering to pickup, haul, and deliver large items for list members. In mid/late April, I will be leaving New York, to arrive in California near the start of May, and I will be passing thru Chicago and Denver on the westbound trio, and likely Minneapolis on the eastbound. If business calls, I can hit other cities as well. I will have a van and a trailer, and can take fairly large items, like 6 foot racks. Weight is not much of an issue, with maybe a limit of 1200 pounds or so. Items hauled on my trailer are fully caccooned and tarped. Loading and unloading are included. I use the hauling to pay for my expenses on the trip (mostly fuel), so my rates are quite reasonable. Smaller items are welcome, of course. Some of my capacity is already taken for both the westbound and eastbound sections, but there is plenty of room for more. Also, from Denver to California I will be almost completely empty. Please inquire off list, please. -- Will

15 years, 2 months

Tubes & Computers of Olden Days

by roger.holmes＠microspot.co.uk

> > Gene Buckle wrote: >> On Thu, 18 Feb 2010, William Donzelli wrote: >> >>> >>> The chances of more tube computers coming out of the woodwork is very, >>> very slim, but it has happened in the past few years. It is actually >>> reasonable to think that someone could have an IBM 650 or Bendix G-15 >>> tucked away in a basement or garage. >>> >> Here's one that last I heard was in service with the RAF: >> >> http://199.254.199.10/BehindTheScenes/lockheed.html >> >> The company that owned it was bankrupted by the training market downturn >> after 9/11. It was sold in 2003. >> > I'm pretty sure Colossus is running again at Bletchley Park. I only > wish I could get over there to see it in person. There are some youtube > videos available. > Later, > Charlie C. To say it is running again is a little bit misleading. A huge amount of work was done by my fellow members of the Computer Conservation Society, including some of the people who designed Colossus in the first place and it is great to have it but Winston Churchill had the Colossi(?) broken up into small bits and so this is a replica, an extraordinarily correct replica but a replica all the same, therefore it is now running, not running again. Apparently they had less problems getting the difficult bits working as the plans had been released from UK government archives, than the off the shelf 'commercial' items, plans of which had long since been lost except for the odd hoarder like me and probably you. Also thing like switches were available off the shelf, with a high priority job they had first call on things and selected Spitfire fighter switches which were then being produced in good quantities and good quality. Roger Holmes

15 years, 2 months

Deep fried inductor...

by wh.sudbrink＠verizon.net

I've recently been restoring an H8/H17 system. Almost all of the problems involved capacitors, including a bad electrolytic in the H17 (diskette unit) power supply. I repaired the H17 supply using a dummy load but apparently the H17 was run with the bad supply before I got it. I say this because some of the tantalum caps on the logic boards of the Wangco model 82 diskette drives popped and/or burned when correct power was supplied to them. I've seen plenty of the "teardrop" tantalums pop, but I've never seen one of the "black suppository" types (used on these drives) go. I believe this was the result of bad ripple in the supply. Anyway, one of the Wangcos now runs perfectly and the other runs fine for a while but fails after about an hour of applied power. The difference between the two is that, on the flaky drive, a cap in series with an inductor did a slow burn, resulting in the inductor having a "nice brown toasty" appearance and a small split in one side that some red resin leaked from. By the way, the only way I know this is an inductor is that it is labeled "L5". It looks like a large beige resistor with too many color stripes on it. Inductors are a weak area in my electronics knowledge. How would you know for sure that one has failed? Does it fail open? Other info: When the drive fails, it can not read any data and, when seeks are attempted on it, it sounds "funny", not the nice sharp click it makes when operating correctly. The inductor does not feel hot to the touch when the drive has failed. I'm out of cool spray. Tonight I will try to apply an ice cube in a plastic bag to it to see if that gets it out of failure mode. Finally, assuming it is the problem, what do I need to replace it? The stripes on it are: Wide silver (covering one end) Red Yellow Brown Gold Thanks, Bill

15 years, 2 months

Solderless breadboarding (was: Re: HP-IB, Amigo/cs80 was Re: hp 9153 floppy & disk)

by joachim.thiemann＠gmail.com

On Wed, Feb 17, 2010 at 13:49, Tony Duell <ard at p850ug1.demon.co.uk> wrote: > The main problem is that those breadboard are terrible. It's not the > clock speed that matters, it's the swtiching time of the IC. Most modern > ICs have ouptus that switch so fast that when you combine them with the > stray capacitances on the breadboard and the relatively high impedance > power connections, you get power and ground lines bouncing all over the > place. Without a _good_ 'scope it's impossible to know why your circuit > doesn't work. If you stick to 4000 series CMOS you'll be alright, but > modern 74xxx familes are pushing it. Really pushing it. But if you're just learning high speed don't matter, even with full computer prototypes. Incidentally, I just saw this: http://blog.makezine.com/archive/2010/02/building_a_cpm_68k_computer_from_s… Crazy, but I'm cheering for him! Retrotastic! :-) Joe. -- Joachim Thiemann :: http://www.tsp.ece.mcgill.ca/~jthiem

15 years, 2 months

Mountain View, CA

by mcguire＠neurotica.com

Is there anyone in or near Mountain View, CA who would be willing to pick up a light PC-tower-sized box and ship it to me? If so, please contact me off-list. Thanks, -Dave -- Dave McGuire Port Charlotte, FL

15 years, 2 months

BBC S.E. news classic computer feature

by roger.holmes＠microspot.co.uk

I'll keep this short, if you are in S.E. England my 1962 mainframe will be on BBC S.E. regional news somewhere between 6:30 and 7pm.

15 years, 2 months

cctech Digest, Vol 78, Issue 24

by jonas＠otter.se

> Message: 12 > Date: Tue, 16 Feb 2010 20:33:58 +0000 (GMT) > From: ard at p850ug1.demon.co.uk (Tony Duell) > Subject: Re: HP-IB, Amigo/cs80 was Re: hp 9153 floppy & disk > To: cctalk at classiccmp.org > Message-ID: <m1NhU7P-000J43C at p850ug1> > Content-Type: text/plain > > some of them may even end up as products :-( I am sure I've told you > how > I once showed a so-called designer who wanted to use a microcontrolelr > module + input interface modules + ... as part of a control system that > his problem could be solved using few lengths of wire and otherwise > unused contacts on his relays and swithces. Hmmm... > > -tony > I used to work for Volvo, developing the maps for ECUs for engine control. One of my colleagues wanted a simple indicator showing the injection time, i.e. for how many milliseconds each engine revolution the injectors were open, to see how his mapping was working out in practice when test driving. He asked for help from the electronics lab, who came up with a proposal for a digital display, all-singing, all-dancing precision device which would cost $$$$$, come in a nice 19" case and take months to design. He went off and made his own indicator instead, using a 555, a moving-coil meter and some passive components. Quite a number of his devices were built for everybody else in the department, IIRC. /Jonas

15 years, 2 months

Living Computer Museum attending the DEC Legacy Event, Windermere, UK, 17-18 April 2010

by RichA＠vulcan.com

Just wanted to let the European readers of CCtalk know that Ian King and I will be at the DEC Legacy Event in Windermere in April, and have been invited to give a presentation on the work we are doing at the Living Computer Museum. Details on the event are available at http://declegacy.org.uk We're looking forward to meeting lots of people there. Rich Alderson Vintage Computing Sr. Server Engineer Vulcan, Inc. 505 5th Avenue S, Suite 900 Seattle, WA 98104 mailto:RichA at vulcan.com mailto:RichA at LivingComputerMuseum.org http://www.PDPplanet.org/ http://www.LivingComputerMuseum.org/

15 years, 2 months

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test-drb February 2010