test-drb

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101090 discussions

by bobvines00＠gmail.com

On Wed, 07 Jan 2015 23:41:59 +0100, Simon Claessen wrote: > > well, > > Good news always has some bad news as well. After careful examining of > the 952 (no, not 850...) pins, I found 52 broken ones. As they are made > of a gold plated springy metal wire, I needed to find a replacement. > Size: 0,5mm diameter. > > Guitar wires are out. They are way to flexible. I opted for fosfor > bronze wire, but could not find it in the shops in Amsterdam. Then I > stubled upon a shop selling beads and stuff to make bracelets and > earrings. They sell "memory wire", A very tough silver coated wire of > 0.6mm. I have no idea what the alloy is, but the mechanical > characteristics are not bad. > > The first clip I made fitted surprisingly good. now to find some time to > bend another 51... > > Oh well. > [snip] Simon, "Memory wire" is also known as Nitinol, a nickel-titanium alloy <http://en.wikipedia.org/wiki/Nickel_titanium>. The Wikipedia page might give you the characteristics you may need. Bob

11 years, 7 months

Resurrecting RK05

by michael.99.thompson＠gmail.com

> > From: Johnny Billquist <bqt at update.uu.se> > Subject: Re: Resurrecting RK05 > > There was also a version of the RK8 controller which did a binary unit > selection. I don't remember the designation of that controller off my > head at the moment. > > Johnny > I believe that it is the RKS8 controller that can access 8 drives. -- Michael Thompson

11 years, 7 months

Broken H724 power supply from PDP-8/e

by michael.99.thompson＠gmail.com

The H724 power supply in my PDP-8/e works OK for about 5 seconds and then the +5V output goes to about 3.0V. If I leave it on for a few more seconds it will blow the 20A fuse for the +5V output. I have the power supply partially disassembled and disconnected from the chassis. I don't see anything obviously fried. There are three ring terminals with two wires each connected to the + side of C205. Two of the wires get hot in just a few seconds. I have not disassembled the wire harness, but I suspect that they are the wires that go to the fuse holder. C205 is the output filter for +5V. The capacitor resistance goes above 3k Ohms if I leave the VOM connected for about 20 seconds, so the cap is not the 20A short. Should I just keep disassembling the power supply and tracing the warm wires? Anyone have experience repairing one of these power supplies? -- Michael Thompson

11 years, 7 months

Stromberg/Carlson, Okuma, Benning, and Computer Autumation Docs

by useddec＠gmail.com

I'm going through boxes of documentation and have a pile 3 or 4 feet high that I don't need. My plan is to try to list some several times a week until it's gone. It varies, but most print sets have manuals and repair notes with them. They came from a repair depot. The pile of Stromberg is 6 to 8 inches high. I keep finding more. i can go through specifics over the phone, but don't really want to type everything. Feel free to contact me off list if you have any interest. There will be a few foot pile of DEC items, but i want to finish this first. Thanks, Paul

11 years, 7 months

Identifying a 16k by 16 core memory board

by kylevowen＠gmail.com

Does anyone know what this board would go to? It's a California Data Processors board, ca. 1978. http://imgur.com/a/AEfWX It was found packaged in a Data 100 Corporation cardboard box, but I am not convinced it really belongs in there. Thanks, Kyle

11 years, 7 months

Another PDP-8 on eBay

by jnc＠mercury.lcs.mit.edu

Another one (an 8/L) starting at a reasonable price: http://www.ebay.com/itm/181630674348 Non-functional, but sounds like it might be close to running. Noel

11 years, 7 months

Weekly Classic Computer Trivia Question (20150105)

by jnc＠mercury.lcs.mit.edu

> From: Rich Alderson > Kanji are *LOGOgrams*, expressing *words*, not *ideas*. Since this is a list about antique computers, not about the technical minutiae of written languages, I elected to use the word that would be familiar to non-specialists, i.e. 'ideogram' (with the common meaning, not the specialist one). >> There is something called the 'iroha' ... It was used to teach writing > this poem was no longer used in schools Which would be why I said it "was used to teach writing", not 'is used to teach writing'. Noel

11 years, 7 months

Weekly Classic Computer Trivia Question (20150105)

by jnc＠mercury.lcs.mit.edu

> From: Chuck Guzis > I suspect that other languages have similar exercises, though > I don't know what the Japanese do in Kanji. Err, think you mean kana, right? (Kanji are the ideograms, there are over a thousand in common use.) There is something called the 'iroha': http://en.wikipedia.org/wiki/Iroha which is a poem which uses every element of the Japanese syllabary - and exactly once! It was used to teach writing, no idea if it's used for the keyboard thingy. Noel

11 years, 7 months

Catweasel support for N*

by snhirsch＠gmail.com

Does anyone have a version of 'cwns' more recent than 0.01? It looks like Andrew Lynch wrote this, but Google did not turn up any work since 2007. It would be great to have a way to generate N* floppies on the CW card. Alternately, has Dave Dunfield's NST ever been ported to work on the Advantage? Google turns up nothing other then references to Kermit (not helpful for disk image transfer) or the Central Point Matchpoint card (unobtanium). I did find a disk image for Advantage N*DOS on Dunfield's site, which may have the ability to run the NST stub, but it presents a recursive problem in that I have no means to write it to a DS N* floppy. I do have a Horizon, but it's fitted with SSDD drives. Any suggestions or workarounds I'm overlooking? Steve --

11 years, 7 months

Understanding DECsystem 5100 Self Test Failure

by bobvines00＠gmail.com

On Mon, 05 Jan 2015 13:24:17 -0700 (MST), you wrote: [snip] > On Mon, 5 Jan 2015, Robert Jarratt wrote: > >> Have you tried buying a DS12887 as a replacement? They are supposed to be >> drop-in replacements, and if yours is already socketed then it should be >> pretty simple to try. > > Yes, I have two of them here. That will be the first attempt and fortunate > then I will be able to stop there if I am lucky. > > -- > Richard Loken VE6BSV, Unix System Administrator : "Anybody can be a father > Athabasca University : but you have to earn > Athabasca, Alberta Canada : the title of 'daddy'" > ** richardlo at admin.athabascau.ca ** : - Lynn Johnston > Richard, Those chips have "battery-backed static RAM" according to their data sheet. Does your system store anything critical in them? If so, you may want to read & save that data so that you can put it back before you install the replacement chip (and add an external battery in a location where leakage won't cause serious damage in the future). I know that some Tektronix 'scopes store their calibration values in the (DS1297 or equal) chip's battery-backed RAM and it is critical to read the info and transfer it to the new chip *before* the original battery dies. Otherwise, you have to either pay ($$$) for or perform the entire re-calibration procedure yourself, if you have the necessary calibration equipment. However, since you said your battery was already dead and you have to reinstall VMS every time the system is powered down, I guess that your system doesn't store anything *critical* in that RAM. Bob

11 years, 7 months

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