the issue was definitely normal electrolytic capacitors. The Dell GX-270 desktop computer was one of the victims. We had over 100 of these and Dell replaced nearly every motherboard due to this specific manufacturer's defect. The electrolytic caps used around the cpu would bulge on the top and in some cases burp out electrolyte out of the top. I didn't research the actual cap manufacturer.
best regards, Steve Thatcher
-----Original Message-----
>From: Randy Dawson <rdawson16 at hotmail.com>
>Sent: Feb 14, 2010 10:45 AM
>To: classic computers <cctalk at classiccmp.org>
>Subject: RE: Getting to dislike tantalum caps
>
>
>Dwight,
>
>There was some criminal stuff going on with electrolytes in this era, from the asian manufacturers. Almost everybody associated with the type of electronics that was not 'throw away' remembers this. I had a note from a pro video repair shop, saying that to get a $15,000 pro video camera back in operation would require the replacement of all the tant caps, as they were all destined to fail, and yet another trip to the shop.
>
>Anybody else recall this? There was one chemical manufacturer pinpointed, that was supplying XR7 or whatever electrolyte to all the manufacturers. They shortcut their process and cut costs, and several years of electronic products were affected.
>
>Please pots your analog computer work! Have you read the Electronic Research Associates books out there (IIRC)
>
>Randy
Cameron or others, not sure if you're interested, but it's time to get
rid of the Tandy PC-4 and all the accessories:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=290402539975&ssPageName=…
I'll be putting a Northstar Horizon Z80 card and an Horizon HRAM5 card
up tomorrow, if anyone is interested.
Jim
--
Jim Brain, Brain Innovations (X)
brain at jbrain.com
Dabbling in WWW, Embedded Systems, Old CBM computers, and Good Times!
Home: http://www.jbrain.com
I've been talking with HP about obtaining VMS sources for the 6.2 release, which we're running on our VAX-11/780-5. Interestingly, they tell me that source for the original release is available, but not the 'updates' which I believe is the patches issued for this particular release. Does anyone on the list have any experience with these subsequent update releases? If so, please respond to me privately at iank at vulcan.com. I'd like to understand what is or isn't included and how they interacted with the original release. Thanks -- Ian
I had excellent results asking for the Matrox QRGB-Alpha board, so I am
trying again.
I notice that there is a section in bitsavers with one manual for Codar
boards,
but not the item I am looking for. There is also a Qtimer II Model 120
which
is not the specific manual I am looking for, but might be useful.
Does anyone know where I might be able to locate a Qtimer II Model 102
manual?
Sincerely yours,
Jerome Fine
Is it possible that you still may have the 200 in 0ne manual for the radio
shack 28-249 electronics kit? I've been searching for a while for this &
would like to turn the kit over to one of the grandchildren but I have no
manual. I realize your post is extremely old but it's worth a shot. regards
Glenn
Hi All,
I'm having a clear out of the loft in the face of an imminent house
move and I need to compress the collection a bit.
On offer are:
1 x Panasonic SCSI LT-7010E Magneto-Optical Drive, no media, hence
never tested but ID'd properly when SCSI hooked up.
1 x Syquest SCSI 5.25 Drive plus 2 x SQ400 44MB cartridges. In working
order when last used.
Both in Chester, UK.
Free if collected. I will investigate shipping costs if anyone is
really keen. MO drive is pretty heavy though.
Cheers,
Pete
--
Pete Edwards
"Prediction is very difficult, especially if it's about the future" - Niels Bohr
On 12 Feb 2010, at 18:00, cctalk-request at classiccmp.org wrote:
>
> Message: 11
> Date: Fri, 12 Feb 2010 15:59:49 +0000
> From: Pete Edwards <stimpy.u.idiot at gmail.com>
> Subject: Re: The value of assembler language programmers [was RE:
> Algol vs Fortran was RE: VHDL vs Verilog]
> To: "General Discussion: On-Topic and Off-Topic Posts"
> <cctalk at classiccmp.org>
> Message-ID:
> <11c909eb1002120759u37cef5e6x4d7e5470b6678d56 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> On 12 February 2010 08:00, Dave McGuire <mcguire at neurotica.com> wrote:
>> On Feb 10, 2010, at 3:15 PM, Roger Holmes wrote:
>>>
>>> the BBC web site. Oh and a couple of weeks ago I posted an old video of it
>>> on U-Tube if anyone is interested the URL is
>>> http://www.youtube.com/watch?v=VsBPuUJPvKg or just Google ICT 1301 and
>>> select video. I hope to post a better one later in the year.
>>
>> ?Man oh MAN that's a beautiful machine.
>>
>> ? ? ? ? -Dave
>>
>
> Seconded! That's an awesome piece of kit Roger.
> I *especially* like the Forbidden Planet noises at the end.
> What is that audio signal derived from?
Thanks to all who responded, I think you will like it even more when you see the new layout with 8 decks in a row, four of which worked at last years open day.
The sound is produced by executing a very small loop of three or four instructions many times which contains a (decimal) multiply instruction, the duration of which varies with one of its operands. Zero takes almost no time, 555555555555 takes longest because for each digit it can either count down for 1,2,3,4 or 5 or count up for 6,7,8 and 9. There is an increment in the loop hence the time varies with each iteration. A conditional branch at the end of the loop flips a bit which drives the speaker.
In the demo software being run in the video there is also a small test for the bottom 2 or 3 digits of incremented value being zero which allows it to branch off and drive the peripherals from time to time. This does no seem to affect the sound too much though it is not quite as pure as the original 'ghost' program. From time to time (but not in the video) it does a bubble sort of a block of data read from tape which produces a more recognisable 'computer' type sound.
I once keyed in a short sequence of jumps activated by some of the switches on the front panel. The longer loops worked fine but there seemed to be a problem with the top note. There happened to be a young lady present and she said she could hear it fine, it seems it was simply beyond the frequency range of my old ears. I think it would flip the bit 1000000 / 12 times a second, so dividing by another 2 that would be 41.666 kHz. The machine has a nominal 1MHz clock derived from a 250kHz timing track recorded on the last drum accessed and the shortest instruction is 12 clock cycles.
As another thread is discussing cats, I have to add that the first time I saw my 1301, there was a cat asleep on the main power stabiliser rack which was stuffed full of 6 inch by 4 inch by 4 inch heat sinks for the GET875 transistors used in parallel to regulate the various voltage DC supplies. It was the rack which was stuffed, not the cat by the way, the cat got up later and played with my host's hands as he tried to operate the main control panel.
> From: Russ Bartlett <arcbe2001 at yahoo.com>
>
> I worked on one of these systems? 400 words IAS , magnet drum, and 4 tape decks .Programming was MPL.? We would use a card sorter (off-line) to save on sort time for a tape sort/merge process.
You've got it, though I didn't know they ever shipped them with just 400 words. I knew it was theoretically possible to have just one 'barn door' but that must have been incredibly restrictive, especially on a tape machine where you need I/O buffers for Data Transfer Unit to do what we now call DMA into/from. Yes it could be programmed in MPL (Mnemonic or machine code or TAS (Thirteen hundred Assembly System) or MAC (Manchester Auto Code) and later there was COBOL and ICT's attempt to make COBOL more bearable, RapidWrite.
Do you mind telling me where this 1300 or 1301 was? I don't suppose you know its serial number do you? I am trying to identify as many machines as I can, especially so I can find out how many were made. Mine is number 6 and I have parts of numbers 58, 75 and 166 but I suspect the number nearly reached 200 but the best remaining official ICT record is incomplete, some pages were lost and it was a marketing document, a list of customers in alphabetical order, and probably made before production ceased anyway as marketing would hardly be interested in an obsolete product.
Your 400 words reflects on another thread where someone said "In the mid 60's only large companies had systems with greater than 16K
memory and disc drives. Mag tape 800 and 1600 bpi if you were lucky was the norm." Taking the middle of the mid 60's, 1965, about a quarter of the machines in the UK were 1300 series with between 400 and 2000 words of Immediate Access Store (core), no discs just usually one 12000 word drum. Those lucky enough to have mag tape (which roughly doubled the cost of the computer as well as requiring air conditioning) were 300 bpi, usually 10 track (4 data + 6 CRC) half inch or for a lucky few, 16 track (8 + 8) one inch wide tape. There were of course scientific machines like ATLAS around but only three? were ever built, most actual data processing was done on much more mundane machines like the 1301. The IBM 360 was announced in 1965 but how many actually got their hands on one in the UK that year? If you only had 400 words (4800 digits) of storage, who would waste it hold 19s. As to using PICTURE XX , I only ever wrote one COBOL program (put me off for life) but I think PICTURE XX means two characters, which means 4 digits so exactly the same storage size as PICTURE 9999.
Roger Holmes.
I have two shelves of pen plotter manuals at work, including many HP ones. Are you after the operators manual or the programmers manual i.e. the command set. I have a DraftMaster (MX plus IIRC) here. Maybe I can answer your questions from memory, if not I can look next week.
Roger Holmes
(Author of MacPlot, a pen plotter driver for Mac which was an application in 1984 but became a chooser level driver after Apple contracted us to change it so they could bundle it with MacProject and what became Claris Draw II).
On 12 Feb 2010, at 18:00, cctalk-request at classiccmp.org wrote:
>
> Message: 2
> Date: Thu, 11 Feb 2010 22:24:59 -0500
> From: jthecman at netscape.net
> Subject: Manual Needed
> To: cctech at classiccmp.org
> Message-ID: <8CC79AA1704C4E9-27F8-7F3C at webmail-m063.sysops.aol.com>
> Content-Type: text/plain; charset="us-ascii"; format=flowed
>
> Hello
> Does anyone have a copy of the hp Draftmaster II manual for loan, sale,
> can make a copy of it?
>
> Thanks,
> John K
