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Re: old computers home brew 72
In a message dated 2/8/07 3:15:12 PM Eastern Standard Time,
bhaskins@... writes: ntel 8008 first up this month 35 years ago.** I attended an application training seminar on the 4004 and did some breadboarding with it, have data sheets and notes somewhere, but this was on company time. Mike Csontos |
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Re: 3S76 Between samples settling time
aobp11
Hello Stan,
I know what you mean, the same happens when the trigger stops during the sweep. On my unit(s), the dot moves very slowly downward then. So it is not a memory leakage problem. The dot patterns I mentioned consist of nice sharp dots. So far nobody reported having a 3S76 without overshoot in 2nd dot. Maybe there is no "problem" or fault at all and I just have (and can, of course) live with it. I'm afraid it is my nature to signal "problems" which are of no practical importance but keep me awake. Thanks for your response. Albert --- In TekScopes@..., "Stan and Patricia Griffiths" <w7ni@...> wrote: you apply triggers to the 3T77 at a 10 Hz rate, this should produce a row ofdots across the screen at a very slow rate. If the memory diodes areleaking, the memory will decay between dots and the dots look morelike "slashes" than "dots". The cure is a new set of memory diodes.---- ---older messages skipped here--- |
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Re: Variac for 577 Curve Tracer Needed (Updated)
Howard Ashcraft
I had the wrong Tek part number. The variac is actually 120-0808-00.
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It is listed as a 0-132 vrms, 1.75z transformer. --- In TekScopes@..., "Howard Ashcraft" <hashcraft@...> wrote:
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Variac for 577 Curve Tracer Needed
Howard Ashcraft
I'm working on a 577 curve tracer. The biggest problem is that the
variable collector percentage variac has a broken winding. The winding is broken near the end, which means that the variac is non-functional throughout its entire range. (It sparks when the wiper crosses the broken winding, too.) Anyway, the part is Tektronix part 120-0831-00. In addition, the unit is missing the pulse button cap which is part no. 366-1402-52 (I think it says 300us). I have emailed Deane Kidd, but I thought I had best ask whether anyone else had these parts, as well. Thanks, Howard Ashcraft |
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Re: old fashioned 535 - first start after 35 years
Stan and Patricia Griffiths
Hi Michael,
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All of the low voltages in your chart must be within 2% of nominal value before you even try to measure the -1350. The first two supplies to work on are the -150 and the +100 which are interconnected and must BOTH work at the same time. It is not easy to tell which of the two supplies is the bad one. Try rotating the -150 adjustment pot back and forth as I have seen a noisy pot cause this sort of problem. Rotating the -150 adjustment a few times may clean up any noise it has. Once you get the -150 and +100 working, then check the +225 and you may find it too is now working. Same with +350 and +500. When all of those are working, then check the -1350 and you might find it is OK, too. I think you said this was a 535 (not a 535A). There are about 7 black capacitors with colored stripes on them in the power supplies that are real problems in 535 and other scopes of this vintage. These caps are called "Black Beauties" and are famous for getting leaky with age. Most of these caps are 0.01uf at 400 volts, but one is 0.01uf at 600 volts. You should change all of these capacitors to new ones. After you do this, check the power supplies again and let me know if they are now working and we can go from there. If the power supplies are still not correct, I have some more suggestions. Stan -----Original Message-----
From: Michael Petereit [mailto:Michael.Petereit@...] Sent: Tuesday, February 06, 2007 9:10 AM To: TekScopes; Stan and Patricia Griffiths Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years Stan, I checked the voltages: +100V = 124V +225V = 203V +350V = 306V +500V = 464V -150V = -144V A lot voltage is below the limits. The main supply is switched to 234V, the current standard voltage is 235V on the power line. I assume the rectifier might be broken. Since the hartley oscillator is powered by the +350V line and coupled with the +340V line according schematics the tube might not run as expected. The frequency must be aroung 50kHz but I do not have a AM receiver to check ans again the dirt inside the scope is expecially around the HV and this oscillator horrible. Any other ideas about the lower voltages ? BR, Michael |
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Re: old fashioned 535 - first start after 35 years
Stan and Patricia Griffiths
Hi Michael,
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Something I forgot to mention that you may not know is that for the power supplies in a 535 to work, it MUST have a plugin installed, otherwise, the load on the power supplies will be too light and they will not regulate. Stan -----Original Message-----
From: Michael Petereit [mailto:Michael.Petereit@...] Sent: Tuesday, February 06, 2007 9:10 AM To: TekScopes; Stan and Patricia Griffiths Subject: Re: [TekScopes] Re: old fashioned 535 - first start after 35 years Stan, I checked the voltages: +100V = 124V +225V = 203V +350V = 306V +500V = 464V -150V = -144V A lot voltage is below the limits. The main supply is switched to 234V, the current standard voltage is 235V on the power line. I assume the rectifier might be broken. Since the hartley oscillator is powered by the +350V line and coupled with the +340V line according schematics the tube might not run as expected. The frequency must be aroung 50kHz but I do not have a AM receiver to check ans again the dirt inside the scope is expecially around the HV and this oscillator horrible. Any other ideas about the lower voltages ? BR, Michael Stan and Patricia Griffiths said the following on 05.02.2007 22:02:
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Re: old computers
Hugh Prescott
This model Compaq is the one that has the motherboard, hard drive and 3.5 FD mounted on a pull out tray under the monitor. No room for a CD. Just enough room to get a cable out the empty slot.
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Something that Compaq designed to compete with the early Mac, everything in one box. Even has a NIC on the motherboard. Power supply is up in the monitor, will not power up unless the tray is all the way in. And I have had too many bad experiences with IDE compatibility to try that. I have about a 50 percent success rate with loading windows on computers and then moving the drive. I had to just lay the CD-ROM drive on the workbench not the hard drive. Hugh Stefan Trethan wrote: On Thu, 08 Feb 2007 20:06:17 +0100, Hugh Prescott <hugh345@...> wrote:Found an old but good WD 345 Mb drive, made up power and IDE driveWould it not have been easier to install 95 on a PC with CD drive, or copy the install directory to the harddisk? |
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Re: EProm burner
Michael Bender
Joe,
Does anyone have an Eprom reader and burner available? I needAny luck on this yet? I've got a programmer that is connected to my 60MHz (yes, that's correct, *Mhz*!) Pentium system with 640K RAM running Win31 that I keep on my bench for programming older parts. I fired it up and it still seemed to work ;-) but I couldn't find a specific entry for the 74S288 in my burner's menu, but I found some corss-reference info here: so if you still haven't gotten anyone to help you, let me know and I'll fire up my burner system again and see if I can do any of the devices mentioned on that page: Signetics MMI TI Harris Raytheon AMD National Intel --------- --- -- ------ -------- --- -------- ----- TS 82S123 (50ns) 6331-1 18S030 7603-5 - - - - 82S123A(25ns) 63S081 - - - 27S19AC 74S288 - Intersil Fujitsu -------- ------- IM5610 7051 OC 82S23 (50ns) 6330-1 18SA030 7602-5 - 27A18AC 74S188 - 82S23A(25ns) - - - - - - - mike |
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Re: 3S76 Between samples settling time
Stan and Patricia Griffiths
Hi Albert,
You may be experiencing what we used to call "memory slash". If you apply triggers to the 3T77 at a 10 Hz rate, this should produce a row of dots across the screen at a very slow rate. If the memory diodes are leaking, the memory will decay between dots and the dots look more like "slashes" than "dots". The cure is a new set of memory diodes. Stan _____ From: TekScopes@... [mailto:TekScopes@...] On Behalf Of aobp11 Sent: Monday, February 05, 2007 1:41 PM To: TekScopes@... Subject: [TekScopes] Re: 3S76 Between samples settling time Yes there is compensation circuitry, but this is mainly before the gate and not adjustable. I measured the bridge signals at the + and - nodes with 600mV SW input and no triggering (and shunt resistor accross Miller cap to keep the bridge at neutral position). At the suspect Ch. A over 10mV spikes appeared, at the Ch. B maybe 2mV. I interchanged the input side diode pairs between channels and the result was the signals also changed from channel. Also the "slope" problem of Ch. A was nearly cured now (total effect about 2mV of 600mV step), the same is in my other 3S76. So it seems that one diode pair has rather high capacitance while reverse biased (it's not DC leakage). Though the pairs have the same and correct GaAs colour dots, their shapes are a bit different. Could be one pair is not original. In the meantime one of the nuvistor sides diodes of Ch. B died (has too high forward voltage now)... I also found over 10mV DC accross the plugin ground connection (from connector pin 9 and soldering tag to chassis) due to bad contact between tag+srew and chassis. (There is a relatively large net current flowing there because of DC filament heating.) Moreover the 3 securing screws in the back plate were loose. This seems all unrelated to the "slope" problem but explained some of the instabilities I noticed before. Albert |
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Re: old computers
Dennis Tillman
The tail-chasing idle pattern is still with us.
It was so popular in the computer world that many companies imitated it. I remember a Prime mini-computer doing the same thing. The most recent incarnation of it is in Windows. As Windows is booting up, a little graphic scrolls a gradually changing blue pattern across the bottom of the screen to let you know everything is still working. 30 years ago I built a LED front panel into my home built S100 bus PC so I could tell at a glance that it was working right. Every line on the buss was buffered and drove an individual LED. The LEDs were organized according to function on the front panel. But I went even further. I incorporated a Run/Stop/Single Step circuit into my system so I could pause the computer anywhere and single step it along to see what it was doing in slow motion. More recently (13 years ago) I created a little circuit that had a row of LEDs on it and a port address on the PCs ISA buss. If I loaded a TSR when the PC booted up the resident software would talk to the port every fraction of a section to increment the light pattern. It ws a crude indicator of how busy the PC was. ---------------------------------------------------- From: David Wise ...I would often snag on the front panel lights, just gazing mesmerized as they went through their tail-chasing idle pattern. |
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Re: old computers
Anyone looking to dispose of / find old computer parts should get in touch
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with the classic computer group - classiccmp.org. Geoff. -------------- Original message --------------
From: Ashton Brown <ashton@...> <snip> Still have a pristine OtronaT CP/M portable w/ 5" green screen - Yahoo! Groups Links -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.441 / Virus Database: 268.17.31/676 - Release Date: 08/02/07 15:04 |
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"new" old computer!
John Doran
Howdy!
I *adore* old computers. My personal favorites were the DEC machines such the PDP-8E. Of course, a big front panel, or "programmer's console," was a must. My DEC PDP-8/E system, purchased at surplus for all of $50, was enormous, heavy, noisy, and rough on the electric bill. The CPU and its bulk storage (a set of three DF-32 hard drives that stored all of 32K 12-bit words each!) occupied a 6-foot rack. All those cooling fans sounded like a jet aircraft. This system was tremendous fun to play with, but I really needed to reclaim the space, and I didn't have much in the way of software (this was back before the World Wide Web; these days, you can get just about anything you want). So, I gave it away... After a while, I was seriously sorry about that. By the late '90's, the classic computer bug was back with a vengeance, biting me like a crocodile! So, I thought about just getting another 8E, or perhaps an 11. After some consideration, I concluded that this would probably not be a good idea--like the Tek 500 series 'scopes, the old minicomputers are becoming seriously ancient. Then, there is that frightful power consumption (most of them were implemented in standard TTL or even ECL). Finally, even when they were new, these machines were pretty much intended to be turned on and left on in a clean, air-conditioned environment--my DF-32 disks, for instance, made a dreadful screeching noise on power-down as the heads descended to the surfaces of the disks, and after just a few on/off cycles, they would "forget" the operating system! That left me with one alternative; to design and build *my own* classic minicomputer! You may see the result on my Web page (brag!): It was easy to build and debug, using nothing more than my trusty Tek 7834 storage 'scope. And, since it's made out of high-speed CMOS logic, it takes only a few watts to run the thing as quietly as a mouse. I have it talking to a restored DECwriter III (LA-120) printing terminal, and I am working on an operating system right now. -John |
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Re: old computers
Michael Bender
d.seiter@... wrote:
Still have few 6502 based single boards like the Aim65, KIM-1Ahh... the KIM-1 brings back fond memories. That was the first microprocessor that I programmed, in HEX on the keypad, since my friend and I didn't have the tape recorder interface. We used it to control stage lights for our disco parties - this was the mid-to late-70's remember! We had to hand type in all the opcodes before each party, and hope that the KIM-1 didn't crash or lock up or reset and wipe out RAM, otherwise we'd be back to typing in the program again while the lights were left in some random state. mike |
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Re: A company with a Tek-of-old type policy 180 out
180 out!!!!!
Here is an item that is so ridiculously fragile that it sometime breaks the same day that it is replaced. An absolute POS that is probably adding a lot to GE profits. "They don't make them like they used to" *100. Welcome to Y2K+ WB15X10022 GE Hotpoint RCA Microwave Handle |
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Re: A company with a Tek-of-old type policy
J Forster
So your shower uses custom ICs built on a technology that is now
obsolete and unable to be fabbed anywhere? Very advanced! (:^p Very likely so. A different shower uses an American Standard CeraMix valve with integral, solar cell powered, digital thermometer. I'll bet that's a custom IC. 8=)) -John |
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Re: old computers
Stefan Trethan
On Thu, 08 Feb 2007 20:06:17 +0100, Hugh Prescott <hugh345@...> wrote:
Found an old but good WD 345 Mb drive, made up power and IDE drive Would it not have been easier to install 95 on a PC with CD drive, or copy the install directory to the harddisk? It gets a little frightened and confused if you put it in a totally different PC (drivers), but it usually survives just fine. If you want to spare it that traumatic experience you can pull the power after the first reboot (before it detects hardware), and transplant. What kept you from running the harddrive internally? ST |
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A company with a Tek-of-old type policy
J Forster
Folks
This is kind of off-topic, but bear with me. It relates to shower units, and a UK supplier. Our shower cubicle bit the dust when the tile grout failed and deposited modest quantities of water into our ground floor. The shower itself was installed when the house was built in 1993, the brand being Aqualisa. As part of the rebuild, I badly did not want to replace the enitre shower system, but rather wanted to replace a number of external trim parts. I was delighted to find that Aqualisa offer every single spare for every shower that they have ever made! From 1986 to present day. All on clickable exploded diagrams. Better still, the parts arrived the next day. And this is for a shower that they obsoleted in 1996. [snip] Heavens!! It's quite easy in the US to get essentially all service parts for any plumbing thing back to at least the 1920s. I've had no difficulty getting an exact replacement core for shower valves installed in 1956 in less than two minutes. There are at least 4 local sources within a 5 mile radius. I picked the closest In fact, it's harder to get parts for new stuff in my experience. -John |
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Re: A company with a Tek-of-old type policy
Denis Cobley
Toyota also had a similar policy until a few years ago.
I had a friend with a 62 wagon and he broke the back window - Toyota actually manufactured a new one in Japan and air freighted it to Australia - pity now they don't even fix major software bugs in the Kluger throttle system. I suppose when they are trying to compete with the throw away products coming from China something has to give. They now adopt the same throw away mentality with their products too. Regards, Denis ________________________________ From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Craig Sawyers Sent: Friday, 9 February 2007 6:25 AM To: Tekscopes (E-mail) Subject: [TekScopes] A company with a Tek-of-old type policy Folks This is kind of off-topic, but bear with me. It relates to shower units, and a UK supplier. Our shower cubicle bit the dust when the tile grout failed and deposited modest quantities of water into our ground floor. The shower itself was installed when the house was built in 1993, the brand being Aqualisa. As part of the rebuild, I badly did not want to replace the enitre shower system, but rather wanted to replace a number of external trim parts. I was delighted to find that Aqualisa offer every single spare for every shower that they have ever made! From 1986 to present day. All on clickable exploded diagrams. Better still, the parts arrived the next day. And this is for a shower that they obsoleted in 1996. In an era where most companies would oblige the customer to buy an entirely new unit, it is such a refreshing change to come across an enlightened organisation who puts the customer first. Of course the Tek content is that back in the golden days of yore, Tek used to have this kind of policy. Alas gone the way of dust. Buy a new unit, Customer if your instrument is more than an nanosecond past obsolete. And only Board-level-servicable when within a knat's whisker of new. So well done Aqualisa! Craig |
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Re: A company with a Tek-of-old type policy
Kuba Ober
On Thursday 08 February 2007 15:07, you wrote:
So your shower uses custom ICs built on a technology that is nowWell, don't be so quick to diss them. They likely have to maintain the tooling for all the old parts, and that takes lots of room and perseverance. Many companies won't manufacture old parts simply because the molds take up too much room in their warehouse. A company with an active product line would need to stock tens of tons of molds for just a couple years of support span. Heck, there are molds, and then there's all the other tooling that's needed, e.g. weld fixtures, drill fixtures, CNC tapes/programs and so on. And they must be really current on their documentation, as in many places the old docs simply get lost, the people change workplaces, and noone may even remember some old products. Cheers, Kuba |
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Re: old computers home brew 72
Intel 8008 first up this month 35 years ago.
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Every connection (hand) wire wrapped. I still have it and it still runs. Have all of the documentation to back up this date. Can anyone beat this date with a privately owned and personally financed home computer? I have met several people who have claimed to be earlier than this but didn't have even the slightest proof to show. Some of the final debugging was done on a (BIG!) Tek scope. I can't remember the number but it had delayed sweep, two carrying handles on top and a CA plugin. Bert Hugh Prescott wrote: Everything from a wire wrapped 1802, low serial # Altair, early IMSI etc. |
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