At 10:24 PM 1/16/2009 -0500, you wrote: KD9VAX, what a great call for a classic computer guy. 73 de N9QQB ----- 535. [Love] What woman says to fond lover should be written on air or the swift water. --Catullus (B.C. 84?-54?) Carmina. LXX 3. --... ...-- -.. . -. ----. --.- --.- -... tpeters at nospam.mixcom.com (remove "nospam") N9QQB (amateur radio) "HEY YOU" (loud shouting) WEB: http://www.mixweb.com/tpeters 43? 7' 17.2" N by 88? 6' 28.9" W, Elevation 815', Grid Square EN53wc WAN/LAN/Telcom Analyst, Tech Writer, MCP, CCNA, Registered Linux User 385531

On Sat, Jan 17, 2009 at 11:33:12AM +0100, Henk Gooijen wrote: ... We had a PDP-8 given to us by the engineering department for our club station at university. We used it for sending rtty both 5 level and 8 level years ago. I got to write one for the -8, even getting it to read rad50 files off of the OS/8 fs. ;-) I wish I had have kept a paper tape of that. Ham and computers just go together so well. fldigi on FreeBSD here. ;-) - 73 Diane VA3DB -- - db at FreeBSD.org db at db.net http://www.db.net/~db

I was a ham nearly four decades ago. I'd thought about getting back into it, but a lot of the fascination I had then, getting cranky old equipment (all I could afford) to work, is the fascination I have now for getting cranky old computer equipment to work. I just got a VAX-11/780-5 up with VMS on TCP/IP.... -- Ian ________________________________________ From: cctalk-bounces at classiccmp.org [cctalk-bounces at classiccmp.org] On Behalf Of steve stutman [steve at radiorobots.com] Sent: Friday, January 16, 2009 8:31 PM To: On-Topic and Off-Topic Posts Subject: Re: hams on classiccmp Paxton Hoag wrote: KL7JT Did it 42 years ago, when I did have time for radio. hihi

This machine was one of a pair bought from a collector who bought from a collector who bought from...? It was interesting noting the differences between the two: for instance, on one the black foam was in fairly good shape (replaced it anyway), but on the other it was falling off in chunks. Both seemed in good mechanical condition. The next step was to ensure electrical integrity. So I replaced every electrolytic capacitor of consequence in the switching power supplies - five in one machine, six in the other - plus the LSI-11 boot machine and RX01 boot floppy. This was expensive! We used Mouser as our source because their stock and prices were the best we found among the established vendors. Even so, there were a couple of instances where it just wasn't possible to buy a large electrolytic with the exact same form factor as the original - the newer ones were smaller! Curse progress.... In one instance (the main filters in the switchers), it was necessary to ever-so-slightly reshape the holes on the circuit board so the new capacitor's posts would line up. Of course, I visually inspected each and every board in both machines to look for heat marks, obviously damaged bypass caps and the like. There were several instances of tin-plated IC sockets, so I did the rock-and-reseat maneuver just as a precaution. After all of this, we carefully brought up the machine. We had a challenge because 120V three phase doesn't seem to be usual practice in US wiring - we had 240V three phase, but that obviously wasn't going to do us any good! Carefully looking through the power distribution unit's engineering drawings, it became clear that DEC used three-phase simply to balance the current load among the legs - in fact, everything runs on 120V. So we used equal care in reviewing the wiring of the warehouse where we keep these machines and found three outlets that were (a) on the same side of the 240V mains and (b) not sharing a breaker and circuit. Those were connected to a three-phase outlet, the VAXen were plugged in and voila! NOTE: we have a team member experienced with commercial power circuits. Don't try this at home - or if you do, be very very careful and be certain that, from any of the three live blades to another, you don't have more than 120V. Now that the machines would power up, I scoped all the power supply voltages to ensure they were really DC, i.e. that I hadn't missed an important filter cap anywhere. All good, so I tried booting from the floppies we got with the machines. I was able to get the basic console to boot - hooray! - but was unable to get the microdiagnostics to run. We had agreed that successful execution of the low-level diagnostics was a precursor to any attempt to install the OS, so this was a roadblock. I learned a lot about the interaction between the LSI-11 boot device and the VAX-11 CPU. The Console Interface Board actually 'lives' in the LSI-11's memory space - it holds the boot ROMS, for instance. So if you remove the LSI-11 to test it, you can get an ODT prompt but that's it. There is a channel between LSI-11 I/O space and the VAX-11, too, and the two machines communicate during normal operation, which is how the LSI-11 serves as the console device. One thing that seemed odd was that when I tried to execute the microdiagnostics, the LSI-11 would halt at 070000. I finally found a listing for the microdiagnostic that showed a macro statement basing the program at that address - but after poking around a bit, I found out it was loading at 071000. I tried starting from there - no go. What I finally figured out was truly bizarre. THERE IS MORE THAN ONE VERSION OF THE MICRODIAGNOSTICS FOR A /785, and the floppy and program names are the same. The only thing that distinguishes them is the 'stock number', i.e. AS-A123 blahblah, and I never found a shred of documentation that associated one or another with a given machine or serial number series. I infer that DEC assumed you'd get your set of floppies when you bought your machine, duplicate them as needed for security, and that was that. They never anticipated people like us, doing 'archaeology' on obsolete machines.... After some investigation, I discovered a key characteristic: the version that didn't work with my machine had a zero-filled first block in the program files, and the ones that did work had some code in that block, beginning with a JMP instruction. We discovered the repository maintained by trailing-edge.com and perused those, together with the EVNDX file from bitsavers.org, and eventually found a full set of diagnostic disk images. We transferred those onto physical floppies using a PDP-11/03 and the TU-58 emulator program I found through Will Kranz's website. Now we were running microdiagnostics - but failing some. I started focusing on one of the two machines because it seemed in better health, but the memory test chains were failing. Of course, they identified themselves on the console as testing MS780A through -D, and we had a -H in each of our machines. It seemed quite possible, from the errors I was seeing, that it was that simple - but I still wanted a good memory diagnostic run. Searching some more, I found that there was a floppy designated RX3 that claimed to be a microdiagnostic diskette - the documentation for the microdiagnostics (from bitsavers.org) pointed you at RX1 and RX2. My study of the microdiagnostic system told me that it was smart enough to allow for extension, because it would look for files with names of a given structure when you told it to proceed. So I dropped in RX3, gave the DIAGNOSE instruction, and wonder of wonders: a memory diagnostic for MS780E-H began running! We passed that one just fine, and began working toward getting the OS installed. We had CDROM media for OpenVMS 6.2, the latest version certified for the VAX-11/785 - but of course, we didn't have any sort of adapter to talk to a CDROM drive. But we'd earlier made a judgement call to use the CI interface for the system device, and had ordered an HSJ50 setup from PSDS in Woodinville, Washington - really cool guys, by the way, I'd recommend them anytime. I anticipated we'd hook a CDROM into one of the SCSI ports, a shelf of RZ drives into another and we'd be off. However, I did not count on the embarrassment of riches we received from PSDS. They fully populated the HSJ with six shelves and configured RAID arrays up and down! It was great, but it didn't leave anywhere to plug in my CDROM. I played with it for a while, loathe to disassemble it, and finally developed a solution. One of the RAID arrays was 'short', with four drives instead of six; the other two were hot spares. So I pulled one of the spares, plugged it into a StorageWorks shelf on one of the MicroVAX 3100s in my personal collection, and copied the installation media onto it with BACKUP ddcu:/IMAGE/NOALIAS target:. I plugged that back into the HSJ, set it up as a single disk unit, and it booted into the install! I found that I actually needed TWO of these: one was the boot device AND target, the other served as the source media under the install program. When I finally installed the OS onto one of the RAID arrays, I used the same BACKUP command to install an image of the media, booted it, and used the single-disk copy as the source media. One diversion that is worth noting: I tried using the floppy based standalone backup floppies we're gotten with the machines. While I could go through the series, I could not get them to recognize the CI-based drives. Given all my other challenges with versions, I suspected this was just another such issue. I finally decided to simply use the CIBOO.CMD file on the boot floppy. However, I needed the 'station number' and 'device number' for the boot device. Station number was easy: our HSJ dual-redundant controller was set up as IDs 0 and 1, so I used the value 0x100 in R2. But device number had me stumped for a bit. I finally figured out the key: the unit numbers defined in the HSJ's configuration correspond to the device numbers! So 'D6' in the HSJ menu - what I'd called the single-disk unit with the install media copy - translated to 0x6 in R3, and things booted fine. Now we were cooking with gas. I had a valid VMS license but not a UCX license. We also had MultiNet media, but licensing looked like it was going to be a challenge. So I tried CMUIP. It installed with no problems, but wasn't finding an Ethernet adapter. I did some troubleshooting on this: the adapter was, of course, housed in a Unibus expansion cabinet, a DELUA. We had a spare and I tried that - no joy. The LEDs on the DELUA did not change with boot, but all stayed on. I scratched my head... ...and noticed that we had two Unibus cabinets, since I wasn't paying any attention to the other machine. I swapped them around - non-trivial, but not too difficult - and the Ethernet card fired up just the way Ken intended. Now CMUIP found the card and everyone was happy! I suspect the problem with the other cabinet is cabling - you know how ribbon cables can be. After a bit of scrabbling around in the wire closet, we had live Ethernet, plugged in a static IP address, and left the room - to go to another room and telnet into the VAX-11. Happy Dance! Overall, I'd have to say that the biggest challenge was overcoming the shortcomings in extant documentation. As I said, I don't think DEC ever anticipated someone like me would be trying to piece things together years after the machine was EOL. When diagnostics fail, the course of action is either 'replace the device' or 'call field service' - perfectly reasonable for the era, but not always a solution today. I also found that some key diagnostics were not in evidence - or rather, appropriate versions of them. For instance, I found a copy of the Ethernet diagnostics, but they would not run under my version of the Diagnostic Supervisor. It's quite possible there's another version of the DS that would run them, but I don't know if it will run on my hardware - perhaps one of these days when I'm really bored I'll find out, but for now I'm just happy to have a living VAX-11. -- isk ________________________________________ From: brad at heeltoe.com [brad at heeltoe.com] Sent: Saturday, January 17, 2009 4:11 AM To: General Discussion: On-Topic and Off-Topic Posts; Ian King Subject: Re: hams on classiccmp Ian King wrote: very nice. Can you describe how it went? Was the 780 previously in moth balls? -brad

Industry folks say that the lifetime of electrolytic capacitors is about fourteen years. Since the filter caps in our machines were significantly (i.e. TWICE) older than that (and some showed physical symptoms of degradation), we replaced them rather than deal with them one by one as they failed. In our experience with our PDP-10 machines, this was (despite its cost) cheap insurance against periodic failures, which can occasionally be catastrophic. The foam on the doors not only serves to cut down on dust into the machine, it also cuts down on the noise in the machine room. That makes me happy. :-) Yes, the machines can be run without it. But since our goal is restoration, we'll replace it - and yes, replace it again in ten or fifteen years. We *are* running the machine off three separate 110V single-phase circuits - apparently you missed that part. Despite your opinion that "it should be obvious", as good engineering practice I wanted to understand how the machine was using the input power before making assumptions. I'd rather spend some time in due diligence than in damage control - or fire fighting! Also, since our interest is historical restoration, we wanted to make use of the PDU as wired rather than try to bypass it with some sort of approach that would feed 110V directly to the various elements. You may be completely correct about how buildings are wired, but our building isn't wired that way. The EE on our team came up with an approach that's working for us. That raises an interesting point I forgot to mention: it's important to determine that the various subsystems are properly plugged into the PDU. When we first tried to bring up the machine, it would pop the main breaker. After some head-scratching, we determined that this was because the fan for the memory subsystem wasn't plugged into an unswitched outlet. If that fan isn't running, there's a signal from an airflow sensor that trips the main breaker! Yes, if the OS doesn't boot that means you have a problem - but what problem? DEC designed these diagnostics to tell you where that problem lies. I chose to minimize my variables. Chalk it up to a dozen years as a software quality assurance manager at Microsoft. Given the expectations of the people who sign my paycheck, I chose the conservative route. I disagree with your opinion on scoping the power supply outputs. In my colleagues' work with the PDP-10s we have, they found that 'weird' problems were often caused by an unexpectedly unfiltered DC line - and DCOK didn't cop to it. I have clean power - under load - to this machine. We have a valid 6.2 license, which is a 'period' OS for this machine. As to your assertion that we would be fine using the hobbyist license with 7.2: I'm not a lawyer, are you? I have used the 7.2 hobbyist release and PAKs for a number of years on several of my own VAXen at home. But this is not 'at home' and I know my 6.2 license is legal and proper. ________________________________________ From: cctalk-bounces at classiccmp.org [cctalk-bounces at classiccmp.org] On Behalf Of Patrick Finnegan [pat at computer-refuge.org] Sent: Saturday, January 17, 2009 12:06 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: hams on classiccmp On Saturday 17 January 2009, Ian King wrote: FWIW, if you can be sure you're going to operate the machine in a relatively clean environment (eg, no carpeting or other things to generate dust), I'd forgo the filter foam, as all it'll do is crumble and block airflow. This also seems unnecessary if the capacitors were still good. The 11/780 I got up and running has one bad psu (de-asserts DCOK every once in a while, and causes the machine to reboot) which may be bad capacitors, but everything else was ok, despite being stored for over 10 years. First, I want to point out that all of the power outlets on the PDU are 120V, 20A (NEMA 5-20R) outlets, so it should be somewhat obvious from that, that the machine doesn't need three phase power to run, no engineering drawings required. :) Also, your statements about three phase power aren't quite valid. You may have had three-phase 240V, but that is unlikely, the typical practice in the US for non-motor loads (lighting, general power usage) is 120/208V three phase or 120/240V single phase. In normal use, the three phase connections on the VAX PDU have 208V between them, and 120V to ground, which is a standard 120/208V three phase system. You can run the machine off of single phase power by chosing up to three separate 120V circuits - it's ok if they're on different phases, having 240V phase-to-phase is OK - and running each one to a different phase, and tying all the neutrals together to the neutral in the machine. In fact, it is a good idea to make sure that you have different phases, so that you minimize the neutral current, otherwise you may end up with melted wiring or fire, and selecting opposite phases will do this for you, as the netural current from opposite phases will cancel either other out. Fortunately, an 11/780 doesn't draw nearly the outlet/PDU rating; I think I measured around 24A total draw at 120V from all three phases on mine, and load didn't raise that too much. I've run it from three 15A circuits (in a building with 120/208V power that I'm not allowed to put in my own outlet for it ;), and it was ok, each phase was around 8A max. Fun. I'd suggest putting a scope (or even better a one-shot that triggers when they go off) "DCOK" and "ACOK" outputs from the PSUs as more important; checking voltages with a DMM is probably more useful. Your OS is probably the best diagnostic that you have. If it doesn't boot, or crashes, there's something wrong, which you can pick a precise diagnostic to examine the problem. Diagnostics sometimes find problems that don't really exist, and miss things that are show-stoppers. 7.x works fine. You should be able to use the hobbyist license, unless you're planning on running the machine commercially. Pat -- Purdue University Research Computing --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

Odd... I run machines considerably older than a VAX-11 and have not had to replace that many electrolytic caps. Yes, I've had the odd one fail, but by no means all of them. I think I've replaced a couple in HP desktop calculators and none at all in the PDP11s and the PDP8/e I would guess I'd replaced many more TTL chips than capacitors in all the machines I've restored. That depends, a lot, on the PSU design. Certainly SMPSUs can do some very odd things if a capacitor goes open-circuit or just high ESR. How much damage that does to the rest of the PSU or worse the rest of the machine depends on the design. I'll agree with you there. A lot of very obscure problems end up being traced to {SU problems, either low outputs, or excessve ripple, or spikes on the output, or.... I always stick a 'scope on them. -tony

On 18 Jan 2009 at 18:35, Gordon JC Pearce MM3YEQ wrote: Most of the electrolytic problems I've seen associated with age have been with the ones inside of sealed "wall warts" where the heat from the transformer eventually cooks the juices out of them. Short of cracking open a fused-together housing, the only viable alternative is to replace the whole thing. How I hate those things! No standard on the connectors--a wart putting out 20vac will often have the same plug as one putting out 3vdc, they often don't have the same brand on them as the device they're powering, take up 2 or more slots on a power strip and can't be reliably operated from a power strip mounted under a table top, lousy wire leads and hidden fuses. The nadir of 20th century technological innovation... Cheers, Chuck

On 18 Jan 2009 at 21:22, Tony Duell wrote: Screws, wow. I remember seeing the transition between wart-with-6- foot-ine-cord-and-screws to screwless-no-cord in Racal-Vadic modems during the 70's. I still have the screwed-together PSUs; all of the screwless ones failed and were discarded. (Old modem PSUs are particularly useful because they supply +/-12 and +5 regulated). The ones in the USA are supposed to be at least thermally fused--but most are made in China, so who knows what's really inside. Now SMPSU wall-warts with fused-together cases are becoming more commonplace. Shame that--they could be profitably repaired. Anyway, sorry for the topic drift. Good to see that someone else hates the bloody things. Cheers, Chuck

Chuck Guzis wrote: It's always surprised me that stuff like that's legal in the US, given the nature of the power outlets; it doesn't need a lot of weight for the device plugged into the wall to tilt slightly and risk the exposure of live metal contacts (heck, normal power cords and pets are a bad enough combination :-)

...and I much prefer that to any nanny-state nonsense that makes things so "safe" that there is literally no point to their existance. g. -- Proud owner of F-15C 80-0007 http://www.f15sim.com - The only one of its kind.

On 19 Jan 2009 at 12:20, Gene Buckle wrote: I have to admit that I'm undecided about that. If it's an item about which I can discover enough information to make an intelligent decision as to its safety, okay I'm with you. But wall warts are sealed units that give up none of their secrets on the nameplate, nor is the contents of the black blob documented. On the other hand, I bristle when I see "No customer-serviceable components inside". How do they bloody know what I can service? Cheers, Chuck

'No user serviceable parts inside' is, I suppose technically correct. On the grounds that when I am servicing or repairing it, it's broken, and therefore I can't be the user of it. :-) If you really want to get me fuming, then simply say 'You're not trained to repair <foo>'. No, I am not. Iv'e never been on any training course in my life. On the other hand, I am darn sure I can repair any electrical or mechancial device given the necessary informaion. Period. I do not need 'special training' to fit a gear in a piece of office machinery, when, I've been working with gears since before I went to scheol, and darn it, I could cut said gear from scratch if I had to. -tony

Fortunately I understand the use/mention distinction :-) -tony

Alas you're right. As I've said before. if a company made a quality machine, with full tehcnicla and service doucmentation (think : those great old DEC and HP manuals) and parts backup, they'd get my business. Alas there's aren't enough peole like us in the world to make that a viable business Oh, I'm happy with a commerically-built supply if I've seen the schematics, know it has adequate protective devices and know the components are adequately rated. I don't have to build it myself. You may find those SMPSU blocks will work from either 115V or 230V mains with now user adjustments. In which case all you need to do to sell the product in any country is supply the correct mains lead [1], which is probably easier than having to have a different wall-wart with the correct outputs for the product. I assume the input connector on the SMPSU is either an IEC plug or one of those figure-of-8 connectors, or at least something stnadard. [1] Don't get me started on moulded mains leads. I have about the same affection for those as I do for wall warts, and for much the same reasons. -tony

Of course in general SMPSUs are lighter than linear supplies of the same output power. So if these brickes seem light, they're probably switchers. 'Figure of 8' is the common (although incorrect for many reasons) name for the normal 2 pin main connector you find (found?) on cassette recorders, radios, etc in the 1980s. I've seen it caleld a 'Telefunken connector', although I suspect that name is dubious too. -tony

On Tuesday 20 January 2009 05:25:38 pm Paul Koning wrote: I've not seen either of the latter two (yet). Of the two laptops here, I have one of each of those, this Sony having the two-pin variant and the Dell I was using before that having the three-pin variant. At one point I had the Dell with me but not the cord (and the battery on that one is unusable) and I had no difficulty in finding one to use. -- 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

Gordon> On Wed, 2009-01-21 at 06:37 -0500, Roy J. Tellason wrote: Gordon> "Figure 8" leads will fit "cloverleaf" sockets anyway, at a Gordon> pinch. Since the PSU is double-insulated it makes no Gordon> difference whether the earth is connected. Odd. The usual assumption is that the presence of an earth wire means grounding is required, and using the device without one is a violation of safety regulations. Then again, it's certainly possible that it merely violates regulations, not reality. paul

On Wednesday 21 January 2009 07:43:36 am Gordon JC Pearce MM3YEQ wrote: Well, yeah, but I didn't own this Sony at the time, unfortunately... :-) -- 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

On Wednesday 21 January 2009, Pete Turnbull wrote: Also, it's used on DEC BA213 cabinets, like a DECserver 500 and VAX 4000/300. Pat -- Purdue University Research Computing --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

On 20/01/2009 21:39, Tony Duell wrote: That is an IEC 320 C7 connector (the original Telefunken design is almost the same) rated for 2.5 amps, and it's very common even today. It's often found on things like laptop power bricks, and digital camera chargers. There's a slightly smaller and much less common version, without the notches that lead to the "figure of eight" name, which is IEC 320 C1. There's one other in not-quite-common use; a C5 is kind of like the C7 but with a third pin -- the earth -- above where one of the notches would be on C7. It's rated for 2.5 amps as well, and sometimes found on laptop power bricks. The common 3-pin plug (without a notch) sometimes quite wrongly referred to as a "kettle connector" over here, is an IEC 320 C13 connector. It's usually made of soft(ish) plastic. The version with the notch (which everywhere except in the States is rated for higher temperatures but not higher current, and is called a "hot condition" connector -- it really is a kettle connector, amongst other things) is a C15 and is usually made of hard plastic (for heat resistance), and the bigger rectangular one is IEC 320 C19. -- Pete Peter Turnbull Network Manager University of York

Do you think that the designers of this stuff have learned which approaches they might want to stay away from? :-) -- 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

On Monday 19 January 2009 03:02:03 pm Tony Duell wrote: I would suspect that a younger crop of engineers coming up might have some bearing on this too. :-) Yes, this point is hammered on pretty well in my "8085 Cookbook", which is one handy reference I have that talks about multiplexing displays a lot. Right, I remember that being one suggestion as to how to deal with it. There was something not too dissimilar in my Oki 92 printer, as well. They used something like 10V for a motor holding voltage, and 30V to kick it -- but apparently you couldn't run them on 30V continuously, as the little protection circuit they put in there would integrate the applied voltage and if it saw too much over too long of a time a crowbar would go into operation and trip a breaker. I suspect that the answer to that one is probably "too many". :-( -- 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

On Monday 19 January 2009 05:11:27 pm Jim Battle wrote: Well yeah! Old phart working my way toward full curmudgeon status... :-) No argument there. There are those who would argue that the market demands cheap crap, too, and that there isn't much of one for quality product that's built to last. I've been arguing that one for decades. I consider the cheap stuff to be a real waste of not only my time and money but also resources like the materials it's made of and the production capability and so forth. And I try to avoid it whenever possible. That's why I like a lot of this older gear so much, it's better made. -- 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

On 20 Jan 2009 at 11:13, Fred Cisin wrote: I'm repeatedly surprised at the number of average folks who can't do math in their heads--or long division on paper. Whippersnappers! Cheers, Chuck

Fred Cisin wrote: Umm $9.95 or $9.99. :)

On Tuesday 20 January 2009 02:28:27 pm Chuck Guzis wrote: Used to be that using a calculator was considered *cheating*. Now they recommend specific models... :-( -- 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

I wonder if part of the change is that the people who buy and use very complex products now are not technically-minded at all. 30 or 40 years ago, I would guess a lot of small-ish computers were ought by engineers or scientists who had some idea as to what went on iside, and could appreciate a good design. And they were prepared to pay for said good design, so that's what got built. Now the average PC owner wouldn't recognise good engieering if it lept up and bit them, they are swayed, alas, by price alone. So guess what gets made... It's a great pity there aren't enough people out there who would pay for a good design for such a product to be comemrically viable. -tony

- 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. Actually I thought the DEC power controllers had a circuit breaker in the neutral leg too just to prevent somebody from doing something like this. The split phase models do - are the three phase power controllers different ? Bob

Um, let's clarify something: there are NO three-phase components in a VAX-11. The switchers, the fans, ALL of it are single phase. Oh, there is one component that's "three phase": the power supply in the PDU itself, which generates the voltage to run the relay that switches the switched outlets. That's fused separately. And yes, the neutral leg has a breaker, too. And yes, this IS a "full config", with RH780, DW780, CI780 and (lucky us!) FP785. -----Original Message----- From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Patrick Finnegan Sent: Sunday, January 18, 2009 9:43 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: Running 3 phase 780s on single phase power (was RE: hams on classiccmp) On Sunday 18 January 2009, Bob Armstrong wrote: This is exactly the point I was trying to get across. I *think* that it does, but without opening one up or digging through bitsavers, I can't remember for sure. I do seem to remember though, that the breaker has the 3 phases, neutral, and a shunt-trip run through it for thermal overload/lack of airflow. Anyways, in my experience on my 11/780 (which isn't a full config), the CPU, memory box, unibus controller, fans, 11/03, and RX01 together draw no more than a total of 24A at 120V, so it may be possible to run the system off of a single 120V supply, but I wouldn't recommend it. Adding anything like a second memory box, DU780, an RH780 or something else to the CPU (does the LSTTL in the 785 draw more or less power than the 780's cpu at their respective clock speeds?) Pat -- Purdue University Research Computing --- http://www.rcac.purdue.edu/ The Computer Refuge --- http://computer-refuge.org

Yes, it's a ganged breaker. Plus there are breakers to each outlet on the PDU, plus there are breakers on the switchers (and other items like the LSI-11, RX01 and BBUs). Those electrons had best behave themselves.... -- Ian -----Original Message----- From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Paul Koning Sent: Monday, January 19, 2009 10:45 AM To: cctalk at classiccmp.org Subject: RE: Running 3 phase 780s on single phase power (was RE: hams on classiccmp) Ian> Um, let's clarify something: there are NO three-phase components Ian> in a VAX-11. The switchers, the fans, ALL of it are single Ian> phase. Oh, there is one component that's "three phase": the Ian> power supply in the PDU itself, which generates the voltage to Ian> run the relay that switches the switched outlets. That's fused Ian> separately. And yes, the neutral leg has a breaker, too. Ian> And yes, this IS a "full config", with RH780, DW780, CI780 and Ian> (lucky us!) FP785. Some peripherals are real three phase, though; the RP06 comes to mind. A breaker in a neutral is odd. I guess it's legal IF it's part of a set of tied-together breakers, so that tripping the neutral breaker also opens the phases. I wonder why they didn't use 3-phase power supplies; that would save space for the filter capacitors. paul

Bob Rosenbloom wrote: ... is temped to upload a photo of Mis Piggy ... The biggest Ham I can think of.

On Sat, 2009-01-17 at 13:44 +0000, Dave Caroline wrote: The UK Foundation licence is 20 quid, and doesn't expire. You need to validate your licence on the Ofcom site periodically but that bit is free. You know you want to. Gordon