test-drb February 2009

test-drb@ccmp.vtda.org

196 participants
309 discussions

by RodSmallwood＠mail.ediconsulting.co.uk

Hi Sounds like capacitors. Alhough it's a switcher any high voltage/high value capacitors in the PSU might well need reforming. Quite often you will see caps with a pair if incised lines on top. This makes them go pop instead of bang. You would not want to see a PSU where they have gone bang. Rod Smallwood The DEC Collector -----Original Message----- From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] On Behalf Of Robert Jarratt Sent: 21 February 2009 19:17 To: 'General Discussion: On-Topic and Off-Topic Posts' Subject: RE: Powering up a 20-year old MicroVAX II > -----Original Message----- > From: cctalk-bounces at classiccmp.org [mailto:cctalk- > bounces at classiccmp.org] On Behalf Of Robert Jarratt > Sent: 20 February 2009 22:45 > To: cctalk at classiccmp.org > Subject: Powering up a 20-year old MicroVAX II > > I have just collected a MicroVAX II which has been in storage and has > not been powered on for 20 years. This is my first machine of such an > age, unfortunately I am not particularly knowledgeable at the > electronics level (I studied circuits academically 25+ years ago and > can solder a bit, but that is as far as it goes). I know I will need > to treat it carefully in order to get it working again. I plan to open > it up and make sure I clear out any debris etc, but beyond that I need > advice from those with the experience and knowledge that I lack on how > to go about powering it up carefully. > > > > Thanks > > > > Rob After removing all the boards and leaving just the disk and tape drive for load I impetuously decided to try powering it up. I knew the PSU (model H7864) was set for 110V and made the switch to 240V (I am in the UK). When I connected the power cord, after a few moments there was a loud pop, followed by another before I could pull out the power cord, smoke rose from the PSU. This sounded just like when I had once accidentally made a 110/240 mix-up. The question is, could it be that I had not made the switch to 240 correctly, or could this just be down to the age of the PSU? Regards Rob

15 years, 5 months

sun HD 'sledges'

by silvercreekvalley＠yahoo.com

Hi - does anyone have any spare Sun 'sledges' for the older pizza-box style Sparcstations? These are used to mount the hard-drives in the box. Thanks. Ian.

15 years, 5 months

Powering up a 20-year old MicroVAX II

by doc＠mdrconsult.com

Robert Jarratt wrote: > After removing all the boards and leaving just the disk and tape drive for > load I impetuously decided to try powering it up. I knew the PSU (model > H7864) was set for 110V and made the switch to 240V (I am in the UK). When I > connected the power cord, after a few moments there was a loud pop, followed > by another before I could pull out the power cord, smoke rose from the PSU. > This sounded just like when I had once accidentally made a 110/240 mix-up. > > The question is, could it be that I had not made the switch to 240 > correctly, or could this just be down to the age of the PSU? I haven't been into a BA23 PSU, so this is a question, not a suggestion - does that PSU have a separate "jumper" plug for 50Hz/60Hz switch? I toasted an RA60 once by just flipping the visible switch from 240V to 110V, not knowing there was a separate physical setting to switch it >from 50Hz to 60Hz. The behavior as it burnt up was just like this. Doc

15 years, 5 months

Electrolytics

by tshoppa＠wmata.com

Will writes: > So even though I was one of the first people on this list > to suggest reforming old capacitors, I have basically > completely reversed my view > on the issue. Now, if the machine is not super old, I will > just pretty much plug in the machine and let it power up. > Even if something does fail, most of the machines I > deal with have enough built in protection > that they will just shut down safely. Some of us do the opposite of using a variac to reform caps - we use a variac to stress-test the components at above the rated voltage. If they blow up now, that's better than them blowing up later. We always called this "margining". I suppose it depends on attitude. To some people a KA630 in a BA123 is a holy shrine to be babied all the way back to restoration. Which I find odd, because there isn't that much that's actually restorable. I mean, 20 years ago I was fixing rubber bumpers in RD53, but who today wants to go through that much work for 70 Mbytes of really slow storage? Maybe I just hate all those stupid MFM drives too much. Tim.

15 years, 5 months

Electrolytics

by jgessling＠yahoo.com

> We always called this "margining". Years ago, I had read a book about the Whirlwind computer developed at MIT. In that book was the claim that margining had been invented during that project, the idea being to increase the voltage and make the weak tubes fail so that overall reliability would be improved after they were replaced. I've wondered if that's really true or was the technique in common practice and it just became formallized at that time and entered into historical lore. Of course Whirlwind was also important for other developments like core memory and employing a young grad student by the name of Ken Olson. BTW, I think the book was: Project Whirlwind: History of a Pioneer Computer by Kent C. Redmond, Thomas M. Smith Digital Press, 1980. Definitely a good read, alas, my copy is miles away. Regards, Jim

15 years, 5 months

AAARRGGGHHHH ... people still stealing my work

by evan＠snarc.net

This was an issue a couple of years ago. Now it's back: the 10,000-word article that I published on my personal web site in 2005 (and since took down) is reprint IN FULL at http://www.iranianpda.com/iPDADB/FAQs/PDAHistory/ThehistoryofPDAs.htm, obviously without my permission. Whatever moron did this even included my disclaimer saying not to steal my work!!! Here are two other examples: Big yellow chart 1/3 down the page: http://um_pxgt_6103.seedwiki.com/wiki/um_pxgt_6103/pda_-_discuss?wikiPageId= 237424 Timeline 1/4 down the page: http://pdaforum.ladoshki.com/viewtopic.php?t=20027 <http://pdaforum.ladoshki.com/viewtopic.php?t=20027&postdays=0&postorder=asc &start=5&sid=772e87081af243f1c20a6cc14bb989ce> &postdays=0&postorder=asc&start=5&sid=772e87081af243f1c20a6cc14bb989ce Can anyone help?

15 years, 5 months

Why Do the OOP Seller's Use RFQ?;Was: Source for bipolar PROMs?

by trag＠io.com

> Date: Mon, 23 Feb 2009 21:03:22 -0500 (EST) > From: Steven Hirsch <snhirsch at gmail.com> > The 571 seems to be pure unobtanium, unless you > count 50 hits of *&ssholes who want you to submit an RFQ and won't deal > under $250 a shot. Does anyone know why those businesses operate that way? Why not just post a price list? A line item on their RFQs is always "Target Price". Well, honestly, my target price is 0, of course. I know I won't hit it, but that's what I'd like. I'm certainly not interested in telling them there is a floor to the price they can offer me. And how is it more profitable to them to let this stuff sit in (costly) storage somewhere, rather than selling fifty pieces to someone who could use them? I've been hunting WD92C32 for a long while and they all seem to be in the hands of *those* people. About once a year I do another search, and the quantity available listings never change. There's plenty of them out there, doing nothing, but try getting your hands on any for less than $5 each. The total value of the thing I want to build is probably $15 so spending $5 on one component is ridiculous. Jeff Walther

15 years, 5 months

RL02's And RL01 Offered Baltimore Maryland

by fsmith＠ladylinux.com

Hi, I have two nice RL02's and a RL01 I am offering either for trade or whatever to whom ever wants to stop by and pick these up. They were part of a E-Pay lot I bought over a year ago and were working when deinstalled. I am looking for a later BA23 case with skins (Hopefully) so I can build my frankenpdp with or anything else including good beer you want to offer. I had to haul them here and store them so something must be offered but I am not asking for much. No shipping as they just are too big. More stuff is coming to be offered up as I have discovered a old love with vintage audio equipment and some of my Dec "Projects" have to be put into the hands of people who will actually use them. -- Kindest Regards, "No Problems Only Solutions" L.B. Network Consultants LLC. Baltimore, Maryland

15 years, 5 months

VCF's this year

by rborsuk＠colourfull.com

Hi All, Has there been any dates for VCF's this year? Rob Rob Borsuk email: rborsuk at colourfull.com Colourfull Creations Web: http://www.colourfull.com

15 years, 5 months

Central Point Option Boards available

by trixter＠oldskool.org

I've seen a smattering of interest around Option Boards in this list every few months, so I thought I'd mention that my last two option boards are now up for auction, an older CopyIIPC Option Board and a Deluxe Option Board: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110355365098 http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110355371748 I set the starting prices at about half what I've seen them go for in the past (and that was for loose boards). -- Jim Leonard (trixter at oldskool.org) http://www.oldskool.org/ Help our electronic games project: http://www.mobygames.com/ Or check out some trippy MindCandy at http://www.mindcandydvd.com/ A child borne of the home computer wars: http://trixter.wordpress.com/

15 years, 5 months

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test-drb February 2009