Not that I condone the replacement of the original power supplies with PC supplies (I don't consider PC supplies any more reliable), but basically your wall outlet supplies 15A at 110v (in the US anyway) which is 1650 watts (P = VI). The power supply converts the 110v at 15A to 5v at 30A (don't know if they really have 30A PC supplies or not), which is only 150 watts. --tom At 12:32 PM 7/31/01 -0500, you wrote:

Ethan Dicks wrote: Well, according to the schematics, each 5V power module supplies only a part of the backplane. So if one goes south, then that would mean that the machine would simply stop due to loss of (logic) signals. The power modules are not connected in parallel. If that would be the case, I guess that the modules would burn themselfs up due to minute voltage differences and exchange current between them. True, the modern PC PSU's are not up to the highest standards, but they deliver 5V@30A and are easy to get. If I would use PSU's from old, well known brand PC's then I'm not stuck with inferior stuff. It also allows me to switch them on one by one, so that the inrush current is not flipping the switch on my automatic fuse. Ed -- The Wanderer | Politici zijn gore oplichters. quapla(a)xs4all.nl | Europarlementariers: zakkenvullers http://www.xs4all.nl/~quapla | en neuspeuteraars. Unix Lives! M$ Windows is rommel! | Kilometerheffing : De overheid '97 TL1000S | weet waar je bent geweest!

On 31 Jul, Bill Bradford wrote: Ahhhmmmm. Yes. ;-) The current by itself is not important, you have to see it in relation to the voltage. This means you can suck a given amount of _power_ out of a wall socket. Power = current * voltage. So you will get with 230V and 15A a power of 3450W out of the wall socket. A power supply is a device that transforms a (usual) higher (AC) voltage into a lower (DC) voltage, thus increasing the current, as the power is constant. So you will get 690A at 5V if you max out the _power_ capacity of a wall socket. But you have also to consider, that the internal components in a power supply will limit the amount of power that can be transported through the power supply. As the output voltage is fixed at 5V (or 12V or what ever) the limitation applies to the current. -- tsch??, Jochen Homepage: http://www.unixag-kl.fh-kl.de/~jkunz/

To make things worse, most European power companies provide a wall voltage of 220V, not 110 as is common in the US. GZ At 12:39 PM 7/31/2001 -0700, you wrote:

I don't normally endorse this rag in any way, but in Newsweek's Aug 6 issue pg 8 (Periscope dept.) "Trading Pickup Lines in COBOL" VCFs and Sellam get a nice little token mention and are charactertured to boot! Congrats Sellam! ;) - Mike: dogas(a)bellsouth.net

I disagree for a few simple reasons: First, there aren't enough systems worth the kind of money that would interest an investor/speculator. You need to get into a five-figure value range and then have a history of value growth over years. The only computer I can think of in that class is the Apple I. Investors want to buy a few things for a lot of money that will appreciate over time. Otherwise, it's too much work and overhead. Second, buying computers as an investment is not like collecting, say, art. If not cared for, many of the most valuable systems deteriorate over time, and with them their value. A speculator would have to invest in maintenance. And then there are the storage and transportation issues involved with larger systems. Finally, no infrastructure exists to broker the buying and selling of investor-level systems (even if they did exist in number). eBay is really just a big yard sale. You don't have the equivalent of a Sotheby's auction house or even of a high-end antique dealer. It took decades for this type of infrastructure to develop for the antique auto hobby. As the hobby grows (and it will whether we like it or not), it will attract attention from mainstream media and people who think they can make a quick buck. (and a buck is about all they will make). The bozos among them will be a nuisance, but in the long run greater awareness of the hobby will result in more systems being saved. --Mike Michael Nadeau Editorial Services 603-893-2379 ----- Original Message ----- From: "R. D. Davis" <rdd(a)smart.net> To: <classiccmp(a)classiccmp.org> Sent: Tuesday, July 31, 2001 6:56 PM Subject: Re: Newsweek mentions VCFe and Sellam issue get animals: & such

On Tue, 31 Jul 2001, Sellam Ismail wrote: [...] Sellam, while I understand this, and agree with you in theory - and know that you've got the best interests computer preservation in mind, I'm not convinced that the world works like that. Does anyone know for certain that more systems will be saved because of a greater awareness of the hobby? Many people are aware that some collect and restore old cars, but that hasn't stopped our idiot governor, Paris Spenddenning, and our state Senatocrats, here in Maryland, from passing laws coercing junkyards to destroy any car over 10 years old within a few days or so of its arrival. -- Copyright (C) 2001 R. D. Davis The difference between humans & other animals: All Rights Reserved an unnatural belief that we're above Nature & rdd(a)rddavis.net 410-744-4900 her other creatures, using dogma to justify such http://www.rddavis.net beliefs and to justify much human cruelty.

If you think about big crook investors (*1) you're maybe right. But Investment on a 100USD up to a few thousand is still a thing to considere. Think about investment in Stamps or old coins. The situation is (collector/investor wise) quite similar. 90% of the items collected are of low value, and not very interesting investor only people. Of the remaining 10% again 9/10th are only of some worth - none of them as a single unit interesting as a big investment (but maybe as a collection). Only in the remaining 1% you'll find units where a single unit may represent significant value to Joe Average. Now we are talking about sums of the 4 to 5 digit range. And among all these zillions of various coins and stanps only a few, a number almost indistinguishable Similar in Computers: For most units the scrap metal value (what a scrap dealer will pay) is higher than the collectors value (what a collector is willing to pay) - as in Coins, where for most coins the value is around the metal value. And the most units, where a price higher than this is possible it's in a low range - and as for Coins/stamps, they are of no value for investment (*2). Now there come in the few systems where a price may be obtained, reasonable higher than average: e.g. Chicklet PET, Altair, SOL, IMSAI, etc. And these are the systems where investment outside of the hobby scene may take place. As a last category we have again the exceptional pices like an Apple 1. In my eyes out of scope for reasonable consideration. (*1) It shouldbe noted that most forms of art investment are _not_ going for the few Rembrands or Van Gochs - these are just the ones who make the news (*2) If I talk here about Investment I always refer to pure money orientated and 'chart' driven investment - not Investment where you'd need some expertise to see a future gain. Now here you miss some of the most important factors in art collections. Just hanging the picture along the wall and waiting for a higher price is the best way to lower your value. Art work of most kind requires a constant maintanance and repair. Even more when you think about 'modern' art forms - 'stuff' made by artists like Beuys or other 'contemporary' artists require extensive skills. And their 'work' was sold for more than a few bucks. Jep, I belive these things will show up during the next 10-15 years. Agreed. Ciao H. -- VCF Europa 3.0 am 27./28. April 2002 in Muenchen http://www.vcfe.org/

On Tue, 31 Jul 2001, Sellam Ismail wrote: I refuse to answer that on the grounds that it may incriminate me. ;-) Don't worry, I'm not; my father is my mother's husband. BTW, who's Wayne Green? -- Copyright (C) 2001 R. D. Davis The difference between humans & other animals: All Rights Reserved an unnatural belief that we're above Nature & rdd(a)rddavis.net 410-744-4900 her other creatures, using dogma to justify such http://www.rddavis.net beliefs and to justify much human cruelty.

to cynical bastards.

Rumor has it that Gene Buckle may have mentioned these words: As was HotCoCo; especially in the early years... "Merch" -- Roger "Merch" Merchberger --- sysadmin, Iceberg Computers Recycling is good, right??? Ok, so I'll recycle an old .sig. If at first you don't succeed, nuclear warhead disarmament should *not* be your first career choice.

As the former editor-in-chief of both 80 Micro and Hot CoCo, I'm flattered. Thank you. BTW, I don't remember Wayne helping out much with article assignments, editing, writing, etc. Not that I'm complaining... --Mike Michael Nadeau Editorial Services 603-893-2379 ----- Original Message ----- From: "Fred Cisin (XenoSoft)" <cisin(a)xenosoft.com> To: <classiccmp(a)classiccmp.org> Sent: Wednesday, August 01, 2001 2:29 PM Subject: Re: Newsweek mentions VCFe and Sellam

Do you liike 'Microcomputing'? Isn't it Kilobaud but later? David Greelish was selling some for $0.50 at the VCFE I picked up two (7-81,1-83). John A.

wanderer wrote: Here are the measurements from my own system I made a while back. Since I am in the U.S., this is a 110 volt configuration. System configuration: PDP-11/70 CPU KB11-C w/FP11-C, 0 RH70's, 1 DL11W, 1 RX211 MK11 1024KW BA11 w/1 DZ11, 1 RL11, 1 KLESI, 1 DELUA, 1 UDA50 RX02 SA72 w/4 RA72 RL02 TU81+ LA120 The entire system is fed with a single 220V 30A circuit which is split into two 110V 30A circuits through an 861-D power controller. Configuration Run current Peak Current L1 L2 L1 L2 CPU only 5.8A 5.2A 6.2A 5.7A CPU+MK11 5.8A 8.9A 6.2A 10.5A CPU+MK11+BA11 9.9A 8.9A 14.7A 10.5A Full load at idle 12.1A 14.1A 17.4A 17.5A Full load with all 12.2A 15.4A disks spun up, tape loading, CPU running EMKA diag. The total current draw would be the sum of the values from L1 and L2. These are observed values from my own system. Your system will never be exactly the same as mine. Don't under-estimate the AC circuits to the equipment. -- Doug Carman pdp11(a)bellsouth.net

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On Wed, 1 Aug 2001, Doug Carman wrote: Actually, you need not short them out to be in trouble. Just hook enough of those suckers end to end and the wiring in the first one gets almighty hot - and perhaps incandesent. A friend did it to himself a number of years back. Rather exciting for a while, what with fire engines and all that. Rather embarassing later trying to explain to his fellow engineers how it happened! - don

On Tue, 31 Jul 2001, wanderer wrote: Grats! My own personal 11/70 is still being elusive, but it's out there somewhere. I'll find it someday! -- Jeffrey S. Sharp jss(a)subatomix.com

On Tue, 31 Jul 2001, Jeffrey S. Sharp wrote: On Tue, 31 Jul 2001, Master of all that Sucks wrote: Is it *available*, or are you just torturing me? :-) P.S. If it is available, e-mail me directly instead of replying to the list <evil grin>. -- Jeffrey S. Sharp jss(a)subatomix.com

wanderer wrote: Actually, I find the 5V regulators easier to work on than the typical PC power supply, although not nearly as efficient. I am not sure that the timing of the ACLO and DCLO lines could be retained if you use alternate supplies. The current from the PC supplies may drop off much faster than the H7420's when AC fails. In practice, I have never had much trouble with the power supplies on my 11/70. Of course, I also have spares just in case I ever do. Yes, H744 K & L can be removed if there are no RH70's. Good idea. Also check the output of the 5V regulators, they must be +/- .1V of 5.00V. The output is very dependent on the stability of the AC input voltage. The biggest thing that is likely to need replacement are the fans. Typically, the 4 in the bottom of the CPU burn up or seize up quicker than the rest. Since there are a total of 17 fans between the CPU and the power supplies, it is almost certain that you will be replacing some. Mine was well cared for before I got it, and I still replaced 6 of the fans. If any look at all questionable, replace them with the highest CFM fan that you can find. I use NMB 4715FS-12T-B50 110V fans as replacements in mine. Make sure you install bus grant cards where needed and check the NPR grant continuity on all the slots that may have had their NPG jumpers cut. Since you said it was all in one rack, I assume the UNIBUS is terminated in the CPU and does not extend to another shelf. Sounds like you have MK11 memory? Be careful about the cabling to the MK11 shelf. Several DEC documents have the connectors mis-labeled on the drawings for the MK11. If you disconnect them, make your own notes first about how they are connected. (I got burned once by following the diagram that was wrong.) Disconnect the battery backup units from the MK11 if the batteries are no longer any good. Also, since you said it is all in one rack, if there is anything mounted anywhere above the CPU in the H960 rack (MK11?), don't install the covers on the front of the rack or the back door. You will not get enough airflow to cool the CPU. DEC really didn't intend for anything to be mounted above the CPU (except for a few shallow components that don't restrict airflow). As far as I know, all later 11/70 configurations in H960 racks required a minimum of two racks, with the MK11 in the second rack. Airflow will be even more important if you don't have it in a controlled environment. Good luck to you. I am glad to see another 11/70 in the hands of someone who will care for it. -- Doug Carman pdp11(a)bellsouth.net

Tony Duell wrote: Good point, I have also experienced this and have gone back to find they need adjustment. . While I admit that I still have some of the original fans in my 11/70, most that I replaced were beyond any repair. I have a local electronics surplus store that sells the cooling trays that US Robotics used to sell with their access servers. These cooling trays had never been used and were made up of nine of the very high quality ball bearing NMB fans that I mentioned. These fans are used by many electronics manufacturers today and are a direct replacement for the original fans in the KB11 CPU. I found that if you have gone to the trouble of taking the system apart to the point where you can get the fans out, you realize that you don't want to do it often :) -- Doug Carman pdp11(a)bellsouth.net

If you do get a chance to look through the VT180 stuff, I could easily drive down to Nashua to pick up a copy of the disks. I'm just in Bedford. Thanks, David Betz dbetz(a)xlisper.mv.com ----- Original Message ----- From: "Megan" &lt;mbg(a)world.std.com&gt; To: &lt;classiccmp(a)classiccmp.org&gt; Sent: Tuesday, July 31, 2001 6:37 PM Subject: Re: DEC VT180 (Robin)