test-drb December 2010

test-drb@ccmp.vtda.org

154 participants
208 discussions

by js＠cimmeri.com

Subject: Re: Using a Variac to revive power supplies From: Tobias Russell <toby at pdp11.co.uk> Date: Thu, 23 Dec 2010 19:06:04 +0000 To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> Ok, I suspected as much. So for a linear supply such as the 8/E's is a Variac a valid way to go or should I reform the capacitors individually as I've done previously? All the best, Toby ------------------------------------------------------------------------ Toby, I've found that removing every single electrolytic and reforming to full (or 10% over) capacity provides the best results. The Variac method -- while better than nothing -- doesn't limit your current... plus doesn't reform all caps to full capacity, nor tell you anything about their condition and leakage. 1. Remove cap. 2. Check ESR. If ok then.. 3. Reform with resistor and variable power supply while monitoring current... raise input voltage slowly to keep max current to no more than 1ma. Let current settle down every so often to check for leakage rates at various voltages... One method I use is halves... start out at 50% rated voltage, let settle, then 75%, settle, then 87%, 95, 100.... Checking leakage at each stage like this gives you an idea of cap condition.. so you can decide whether to replace or not. 4. Check ESR again. 5. Check capacity. 6. If capacity is within 10% of spec, ESR is what it should be, and your leakage rates are acceptable, then you're good to reinstall. Otherwise, replace! - John Singleton

13 years, 4 months

OT: Harris TS22 buttset repair

by dgriffi＠cs.csubak.edu

I had to pass up a gig because my buttset ran down its batteries. That's not much of a problem except that I found out that the Harris TS22 series has an irritating little problem of locking up if both the 9V and 3V batteries are both dead. Does anyone here know how to get a TS22L unlocked without sending it out for repair? -- David Griffith dgriffi at cs.csubak.edu

13 years, 4 months

Using a Variac to revive power supplies

by toby＠pdp11.co.uk

I've recently acquired a Variac (220V 10A) and was wondering what the collectives views are on using them to revive long dormant power supplies. Previously I have removed the electrolytics and reformed them with a bench power supply setup, slowly ramping up the voltage (as per http://www.vcomp.co.uk/tech_tips/reform_caps/reform_caps.htm). Am I right in thinking I can use the Variac to effectively reform the capacitors in circuit? I'm currently rebuilding one of my PDP-8/E's which has a linear PSU which I believe is ok, but will it also work with later DEC switchmode PSUs? All the best, Toby

13 years, 4 months

HP 10276A LSI-11 Logic Analyzer Probe Interface

by glen.slick＠gmail.com

HP 10276A LSI-11 Logic Analyzer Probe Interface I just picked up an HP 10276A LSI-11 logic analyzer problem interface off of eBay. It was listed simply as a 10269C but it looked like the attached card was a Q-Bus card so I bought it and it turned out to be an HP 10276A. I can't find any information about the 10276A on the net. Any chance anyone on this list has a manual for the 10276A? I posted some photos of the 10276A card here: http://sites.google.com/site/glensvintagecomputerinfo/ If I can get this card to work with my logic analyzer it might be useful to help debug why I cannot successfully install 2.11 BSD from a tape drive attached to a CMD CQD-200 while the installation works fine with a CMD CQD-220. Probably some sort of compatibility issue in the 2.11 BSD TMSCP driver. -Glen

13 years, 4 months

Bob Bishop, Apple R&D co-founder, speaking at KansasFest

by pneubauer＠bluerwhite.org

KANSAS CITY, MO -- December 17, 2010 -- Bob Bishop, co-founder of Apple's R&D lab, will be the keynote speaker at KansasFest 2011. Bob is part of the early history of the Apple computer and has developed numerous commercial software titles, worked side-by-side with Apple co-founder Steve Wozniak, written a book on assembly language programming, and published articles in most Apple II magazines. Bob has lived what most of us only dream about, and he has the stories to prove it. In 1976, Dr. Bishop knocked on Steve Jobs' door and ended up owning an Apple I. Soon, he bought one of the first Apple II computers. A few months later, the first graphical Apple II games, like Rocket Pilot and Star Wars, came from Bob's keyboard before Apple had even finished the documentation. Later, Bob brought speech to the personal computer with Apple-Talker and Apple-Listener. In 1978, Bob and Steve Wozniak founded Apple's research and development division. His program Apple-Vision was included on DOS 3.3 master disks, demonstrating the audio and video capabilities of the Apple II. Even after retiring in 1981, he continued using, programming, and writing about the entire Apple II line. The stories do not end with the Apple II. Bob has hosted a radio show using the "Mr. Logic" personality, written essays, founded a comic book club, designed a computer programming language, and written online riddles. Alas, Bob has not yet founded the fanciful "Subroutine Shack" stores "for supplying software components." Today, he lives in California, still "plays with computers," and laments that his Web site is forever under construction. KansasFest 2011, the 22nd annual Apple II conference, is set for July 19th through July 24th at Rockhurst University in Kansas City, Missouri. KansasFest was originally hosted by Resource Central and has been brought to you by the KFest Committee since 1995. Any and all Apple II users, fans, and friends are invited to attend this year's event. Registration details will be announced on the KansasFest Web site in early 2011. For photos, schedules, and presentations from past year's events, please visit the event's official Web site at http://www.kansasfest.org/. CONTACT: KansasFest 2011 http://www.kansasfest.org/ http://twitter.com/kansasfest/

13 years, 4 months

Micro Craft Dimension 68000

by aek＠bitsavers.org

I've put up some docs and software for this machine today. If someone has the schematic/rom/bios source kit that was available, I'm interested in adding that to the archive as well http://bitsavers.org/pdf/microCraft/ http://bitsavers.org/bits/MicroCraft/

13 years, 4 months

HP-85 score

by legalize＠xmission.com

Picked up an HP-85 the other day, including the HP7470A plotter, GPIB interface for the plotter, ROM library with a couple ROMs, 16K memory expansion, carrying case, manuals, and DC100 tapes. The thing is in very good physical condition, obviously having been cared for by its previous owner. I bought it from the owner's ex-wife for $50. Pics: <http://picasaweb.google.com/legalize.slc/HP85> -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://legalizeadulthood.wordpress.com/the-direct3d-graphics-pipeline/> Legalize Adulthood! <http://legalizeadulthood.wordpress.com>

13 years, 4 months

Service bureaus (Was: Tek 4051 firmware listing

by jonas＠otter.se

On Sat, 18 Dec 2010 19:10:13 +0000 (GMT), Tony Duell wrote: >> UofO teaches mostly football, it seems. It's been suggested that it >> be renamed Phil Knight University. Last year construction was >> finished on an academic center for athletes (big glass cube). Now, > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Isn't that a >contradiction in terms? Now now, Tony, you are being unfair. I don't know about those Americans who play that game where they run around in padded suits and helmets, wrestling each other to the ground (I think they call it football for some reason), but not a few European athletes are intelligent people who do very well in ordinary careers when their athletic career is over. And you do know of course that Dolph Lundgren has a master's degree in chemistry? And he has studied at MIT... Brawn doesn't preclude brains. /Jonas

13 years, 4 months

PDP-11/45 power cords

by wdonzelli＠gmail.com

This past Saturday at the Retro Computing Society's mill space we took a good hard look at a PDP-11/45, with hopes to get it running. It is in pretty good shape, and has been upgraded quite a few times over its career running some chem lab equipment. We did, however, find that pretty much every line power cable in the system had started to decay (did DEC buy a bad batch of cords?). They are covered in extremely sticky goo, and every solvent we threw at it would not clean the cords up. I think the cords need to just be replaced., as clearly they have started something that can not be good. So...RCS is looking for official DEC 120 VAC 14-3 power cords with the early/mid 70s type molded-in power connectors, in nice condition, of course. Do you have some DECjunk with these power cords? We are interested (and will make it worth your while) if you can disconnect them - decently long lengths would be nice. Let me know of list. Thanks! -- Will

13 years, 4 months

DiscFerret: speed-ups, API improvements and a mailing list

by classiccmp＠philpem.me.uk

Hi guys, I've spent the past two days working on the Python API and Firmware for the DiscFerret. This work has resulted in a few enhancements... Firstly, I've made the RAM access routines a heck of a lot faster. How much faster? About SEVEN TIMES. The 001A firmware can access RAM at about 30Kbytes per second (peak is ~31KiB/sec during a RAM read). Upgrade to Firmware 001B, and this increases to ~220 KiB/sec, or very close to the theoretical limit of the Microchip USB engine (which is about 250KiB/sec). I'm looking for other ways to boost the transfer rate, but I think this is as far as it's going to go. To put this in perspective, if we assume that it takes one second to read a disc track, and that we get 128Kbytes of data from that read... 80 tracks double-sided = 160 tracks 160 * 128 = 20,480 KiB = 20MiB 20480 / 220 = 93 seconds to transfer the data (only!) Disc rotates at 300RPM. 60 seconds / 300RPM = 0.2 seconds per revolution If we wait for the second index pulse before reading, that's a maximum wait of 0.4 seconds, plus 0.2 seconds to read each track = 0.6 seconds per track, excluding seek 0.6 * 160 = 96 seconds 96 seconds + 93 seconds = 189 seconds... or three minutes and nine seconds. If you reduce the clock rate from 80MHz to 40MHz, that halves the amount of data which needs to be transferred, thus bringing the time down to 141 seconds, or two minutes and twenty-one seconds. Did I mention that -- at full speed -- this is about 30 seconds faster than the SPS Kryoflux analyser? If you're happy with Catweasel-level accuracy (~20MHz acq frequency), then you can get this down to 117 seconds... a shade under two minutes per disc. Admittedly, to get this speed-up, you need to reflash the firmware -- short the BOOT jumper, plug in the power cable and USB, then use mphidflash to upgrade the firmware. Unplug the cables, remove the jumper, then plug the USB and power cables back in. Simple! Next up -- the Python API now handles RAM access chunking. Tell it to read 512K of data, and it'll run off and figure out how many READ commands need to be sent, and how to read those bytes from the hardware in the fastest way possible (i.e. how many bytes it can stuff in each packet). It's also fully backwards compatible with the 1A firmware, although you'll hit the 30KiB/sec speed limit... I've also set up a mailing list -- it's open-access, sign up and you can post, or you can skim the list archives as much as you please. I'll be posting news about software updates, answering questions, and helping out with hardware issues. The mailing list homepage is: http://mail.discferret.com/mailman/listinfo/discferret-l_discferret.com If for some reason you don't like the Mailman web interface (or it refuses to play nice), you can also subscribe to the list by sending an email to discferret-l-request at discferret.com with the subject "subscribe" (no quotes). I'll be posting a slightly longer message there in a few minutes detailing exactly what you need to do to upgrade a Release 1A DiscFerret to Release 1B, including a new firmware HEX file. I should probably turn the DiscFerret site into a semi-closed Wiki (some pages protected, others open, "if you're on the mailing list you can edit the Wiki"), though that's a job for later... I'm also toying with the idea of offloading data separation onto the DiscFerret FPGA, meaning that you'd be able to program the data separator, then just grab a stream of clock and data bits instead of the timing stream. Less effort if all you want is an ADF file, and less data to transfer too... Enjoy! -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

13 years, 4 months

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test-drb December 2010