test-drb January 2009

test-drb@ccmp.vtda.org

218 participants
340 discussions

by djg＠pdp8.net

>I was checking in case they fitted my ASR33 but it uses narrower ones. >I see lots of Teletype paper and paper tape on eBay but never ASR/KSR/ >RO 33 ribbons. Probably easy to get if you know what to ask the >suppliers for. > Teletype ribbons are standard typewriter ribbons of the type with rivets /eyelets at the end to automatically change the ribbon feed direction. Should not be difficult to find. Ones with Teletype on the box occasionally show up on ebay but I haven't seen one go by recently. The Okidata Microline 80 etc ribbons are the style you need for an ASR33 and may be easier to find in a search. Random matches from search http://www.officesupplyoutfitters.com/okidataml80.html http://cgi.ebay.com/Okidata-Microline-80-82-92-Ribbons-Qty-7_W0QQitemZ26015…

15 years, 11 months

Looking for a mac iifx and an apple 2e

by brianlanning＠gmail.com

Hi everyone. I'd like to add a mac iifx and a later model apple iie (or possibly a 2gs) to my collection. I might also be interested in a mac cube, a working IBM PC-AT (5170), or maybe more amiga hardware I don't have. For trade, I can offer up a working amiga 2000 with a hard drive (sans keyboard and mouse probably). I also have some video editing hardware that I believe is from the late 80s or early 90s. I have three giant professional JVC (iirc) VCRs, two playback and one record. I also have what I think is an abner 2 editing controller and a FOR-A FA740 time based corrector. I have no idea how to use the video editing stuff. This came out of a working video editing lab. I'm in the north suburbs of chicago. Let me know if you're interested. Maybe we can work something out. Thanks. brian

15 years, 11 months

Oxidation

by chrism3667＠yahoo.com

I don't know. You can use electrolysis to derust metal (loads of links available). Is there a similar process for other types of oxidation? --- On Mon, 1/19/09, Teo Zenios <teoz at neo.rr.com> wrote: Can't you buy an Aluminum Oxide stripper?

15 years, 11 months

Oxidation

by chrism3667＠yahoo.com

Well there's been some discussion about this. It is possible to *charge* a surface w/an abrasive, but usually this happens as a result of 2 metal surfaces coming into somewhat vigorous contact, w/an intervening abrasive. By comparison I would have to think the adverse effects are minor, but it might be a valid concern. I would think to make tiny flecks of metal or other substance imbed in a surface, you'd have to push pretty hard. But some loose particles could catch on porous surfaces possibly, though I'm not sure they'd tend to stick there permanently. But who knows. ?I have asked how you could test a surface to see if it was charged w/particles, but thus far no answers. Perhaps some type of fine paper or plastic if rubbed on the surface would alert to the presence of icky stuff. But then again how would you distinguish that from the jagged surfaces of metal itself? --- On Mon, 1/19/09, William Donzelli <wdonzelli at gmail.com> wrote: From: William Donzelli <wdonzelli at gmail.com> Subject: Re: Oxidation To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Date: Monday, January 19, 2009, 10:22 AM -----Inline Attachment Follows----- > Steel wool? No, using steel wool on many other metals will later result in more corrosion. Steel wool leaves behind tiny bits of metal embedded in the metal, and these can cause problems if there is enough moisture. -- Will

15 years, 11 months

Oxidation

by chrism3667＠yahoo.com

gingerly. Fine steel wool (uh, #000 or #0000) is available at craft stores. Scotch Bright pads also. Use a lubricant, light oil (even cooking/vegatable oils), or paint thinner/mineral spirits, even water (like when you wet sand a paint job). Be careful of the refuse that will result. I'm not familiar w/this equipment, might need to do some dismantling. Rinse the surfaces thoroughly. I'm no expert.. --- On Mon, 1/19/09, Roy J. Tellason <rtellason at verizon.net> wrote: From: Roy J. Tellason <rtellason at verizon.net> Subject: Re: Oxidation To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Date: Monday, January 19, 2009, 8:28 AM -----Inline Attachment Follows----- On Sunday 18 January 2009 11:23:42 pm Mike Loewen wrote: >? ???I'm in the process of rejuvenating an IBM model 29 keypunch, and a > couple of areas have some sort of oxidation on them.? The card drum is the > worst: > > http://sturgeon.css.psu.edu/~mloewen/CardDrum.jpg > >? ???The steel parts are fine, but the rest has a white material over most > of it.? I'm not sure what sort of metal it is, looks a bit dark for > aluminum but the white material looks similar to aluminum oxidation. I'll bet that stuff's galvanized (zinc-plated). > What's a good approach to cleaning it up? Steel wool? -- Member of the toughest, meanest, deadliest, most unrelenting -- and ablest -- form of life in this section of space,? a critter that can be killed but can't be tamed.? --Robert A. Heinlein, "The Puppet Masters" - Information is more dangerous than cannon to a society ruled by lies. --James M Dakin

15 years, 11 months

xenix redux (or, how to bring back a dead xenix pc)

by brad＠heeltoe.com

This is a short story about getting data off an old xenix pc. delete now if that is not interesting :-) A while ago friend brought over an old pc which was dead. It's a 386 Compaq, very old. It had been running xenix and it was never turned off but one day the power failed. When the power came back it would not boot - the clock battery was long since dead and had lost it's disk setup. Inside is a 386 with about 4mb of ram and a Compaq ESDI controller. And a dead Dallas clock chip. I dremel tooled the Dallas clock chip and soldered in a new battery pack. I got a floppy disk image to reset the bios from someone here (thanks!) But despite many tries it would not boot. The diag program would not let me set the disk parameters exactly the way they needed to be set. most frustrating. So, I yanked the controller (ESDI), changed the jumpers and put it in another old pc which had linux on it. I booted linux and gave it the disk geometry via the command line ("hdc=1224,15,34") Once in linux I made an image of the disk using dd. It turns out that the "conv=" option is very important. I used "conv=noerrors,notrunc,sync". Originally I use "conv=noerrors" and the resulting image was bad because the disk had errors. dd conv=noerrors,notrunc,sync if=/dev/hdc of=disk.img I then put the resulting disk image on another linux box and wrote a tiny C program to search for valid sysv super blocks. It found 3. I then used "dd" to copy part of the image, with an offset (the start of the first superblock), to a new file. dd if=disk.img of=d4 bs=512 skip=2040 With that I had a valid sysv file system in a single file. I then mounted the new file using the loopback option: mount d4 /mnt -t sysv -o loop and viola! I could see all the files and could make a tar file of the root directory. Flush with success (don't you just love it when things actually work? :-) I decided to try and boot it. I used a recent copy of qemu and told it the geometry of the original disk qemu -hdachs 1000,15,34 -boot c -hda disk.img Much to my shock, it booted xenix, cleaned the file system and gave me a login prompt. Now I just have to clean up the mess in my office :-) Man that thing had a lot of dust and dirt in it. -brad

15 years, 11 months

Running 3 phase 780s on single phase power (was RE: hams on

by bob＠jfcl.com

>Roy J. Tellason (rtellason at verizon.net) wrote: >Ah, THAT was the missing piece... >Now I understand what the concern is with this stuff! Right - the issue is with the original PDU, which Ian specifically said they did not rewire. That means one neutral, both inside the PDU, in the power cord, and in the power plug. The loads inside the 780 (which are single phase, as Ian said) have nothing to do with the issue. So, the 780 PDU has a three phase wye power cord (five conductors, including ground). I'm betting that they have a 220V split phase circuit to run it from, so they've wired two of the three phases together for one side of the 220V circuit, and the third phase to the other side. Best case, assuming the loads inside the 780 are balanced, that would make the neutral current the same as one of the phase currents. But that's not really a safe situation - if any of the internal loads within the 780 is turned off, disconnected, or blows its own breaker, then the neutral current will _increase_ due to the imbalance. Worst case in this situation the neutral current would be 2x normal. They probably get away with this because the PDU isn't loaded to anywhere near it's rated capacity. And let's hope they really aren't running it from three separate circuits on the same phase. Were it my 780, I'd rewire the PDU to be 220V split phase (just redistribute the third phase's outlets amongst the other two). The result would only have 2/3rds the current carrying capacity of the original, but it'd be a safe arrangement. Bob

15 years, 11 months

Running 3 phase 780s on single phase power (was RE: hams on classiccmp)

by roger.holmes＠microspot.co.uk

> >> Ian King (IanK at vulcan.com) wrote: >> We *are* running the machine off three separate 110V single-phase >> circuits > - >> apparently you missed that part. > > People need to understand the danger in this - in any multiphase > power > system, the neutral current is the DIFFERENCE of the current in the > individual phases. If the load is perfectly balanced, then the > neutral > current will be zero. > > But, if you run the same load from three separate single phase > circuits > and (worst case) the three circuits are all the same phase, then the > neutral > current will be the SUM of all three phase currents. That's 3 times > what it > would be otherwise and runs a serious danger of melting the neutral > and > starting a fire. I agree with all but the last bit, because if he's running it from three separate supplies, surely he will have three neutral conductors, so no problem. Roger Holmes (Who has a 440v three phase computer drawing 13kVA which has three phase bridge rectifiers to generate fairly ripple free DC)

15 years, 11 months

Wall warts; was: hams on classiccmp

by jeff.kaneko＠juno.com

-- "Chuck Guzis" <cclist at sydex.com> wrote: On 19 Jan 2009 at 3:15, jeff.kaneko at juno.com wrote: >> I don't bother fixing Nokia wall-warts, for example. I do have >> one here on my desk made for Motorola (13.5V @1500mA), though, >> that has been taped together. I do what I have to to keep stuff >> working around here . . . . > >I wonder if you could fuse the pieces back together with a little >methylene chloride... Oh yeah, also MEK, Brake Part Cleaner, 'Super Glue' :^P. But then I'd have to split it again if I pop the fuse again. If I *really* worry about the mechanical integrity, I use a zip tie . . . ____________________________________________________________ Click now and find huge savings on quality rechargeable batteries. http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw1XmCze37rl1hX3xGNCO2sN103…

15 years, 11 months

Wall warts; was: hams on classiccmp

by jeff.kaneko＠juno.com

-- "Teo Zenios" <teoz at neo.rr.com> wrote: >> I probably should try to repair the ones that have switchers in >> 'em, but I have neither the time nor the expertise . . . (sigh). > >I toss mine and get them from the local thrift for $1 or so, can't >stand split open plastic cases. Actually, I don't like it either, but alot of times I have to deal with wall-warts that either have strange voltages, strange plugs, or a particularly high current rating. These usually aren't readily available at the local thrift (although I have gotten lucky). I don't bother fixing Nokia wall-warts, for example. I do have one here on my desk made for Motorola (13.5V @1500mA), though, that has been taped together. I do what I have to to keep stuff working around here . . . . ____________________________________________________________ Click to get free information on how to copy DVD's. http://thirdpartyoffers.juno.com/TGL2141/fc/PnY6rw2oHlnHrAuwX0fE4ZNUDUYIuz0…

15 years, 11 months

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test-drb January 2009