EEVblog 1404 - The Amazing HP 9845B Computer
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- čas přidán 22. 08. 2024
- The HP9845B 16 bit computer was revolutionary in 1979 and the early 1980's, find out why.
The 9845C colour version of this created the amazing war room images for the movie War Games
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#ElectronicsCreators #HP #Vintage
Perhaps you noticed that the colors of the ejector tabs agree with the last two digits of the PC board part number. In my first engineering job at HP in 1979, I used one of these to help design the HP3478A multimeter. I discovered that if I was able to replace a for loop with an incredibly complex matrix expression, the program would run much faster. A friend of mine told me that he studied the 9845 BASIC speed in order to improve the 9826-to-be. He found that the attitude of the 9845 programmers had been that the BPC (16-bit processor) was so fast that they didn't have to worry about optimizing the code. Every one working on a BASIC subsystem* added a few lines of assembler code that was executed for every line of BASIC source code. Thus, there was a very large time penalty for every executed line of BASIC code. They got a lot smarter on the 9826, and the 9826 BASIC ran much faster than the 9845.
* I suppose things like, Has there been an external IO event to handle? A timer event? A keyboard key? Tape drive? Does the display need servicing? Did we just do a computed goto? What is the next line of code to execute?
Thanks Rich. I've done another video of a bit of HP gear that had resistor colour coded ejector handles. How long did you spend at HP? What other projects did you work on?
@@EEVblog I was at HP/Agilent for 23 years. After the 3478A multimeter, came the 3526 2-channel synthesizer. I worked on the re-design of the HP3585A spectrum analyzer, to HP3585B. The 3585A used the same BPC processor as the 9845. When I got done replacing the BPC with a 68000, the card cage was almost empty. I think there were about four boards that all crunched down to one. One of the power supplies (-12V?) ended up only powering a fan, so we rewired the fan and got rid of the power supply. I re-wrote the assembler code in modcal (a modular version of pascal). I discovered one bug in the process, and successfully reproduced another one that was subsequently discovered.
There was an automatic guided vehicle (AGV) that gave me a silly patent. A robotic leaded part insertion robot that needed a tech to run it, and he would insert the parts by hand when the robot was broken, with greater speed and higher quality :). A couple of FPGA projects. A DSP option for an RF spectrum analyzer. I designed the digital board. While I was designing it, I kept telling the boss that he needed to assign a programmer so that the programmer could tell me if I was doing the hardware right. When I finished the hardware, they gave me the programming job. We put Linux on the option board, which communicated with the HPUX processor running the main box. The smartest thing we did was to write two network device drivers that could talk to each other, and we suddenly had a world of development tools at our disposal.
I had the privilege of working with top-notch people creating some ground-breaking products.
@@richaw42 Awesome, thanks Rich. Please send me an email dave@eevblog.com as I can't find your contact details.
@@EEVblog I can't wait to have you host Rich on the Amp hour! Or perhaps even a CZcams interview video!
@@EEVblog - I also would love to see you host Rich Wilson in a you tube interview. Many thanks to Rich Wilson for responding to Dave and to Dave for this video!
What an HP masterpiece, thanks for opening up! Same processor as in the 9825, but with the addition of the extra address extension chip to expand the addressable memory, which was the main limitation of the 9825. And why use only one processor when you can have two! The thing is a beast, it’s huuuuuge. Has little rollers on the back so you can move it around on your bench with just one person. I have resisted so far the temptation of getting one because of it’s sheer size - says the man with 3 IBM 3420, 800lbs tapes in his garage ;-). BTW, War Games pictures where not taken by photographing the monitor, resolution would have been too low. Instead, the HP 9845 was connected to a monochrome HP 1345A vector display with 1024x1024 DAC resolution, but still does not have enough lines per inch to display it. This in turn was connected to an HP 1336A which is a super resolution medical monitor, small but with something like 1000 lines per inch resolution. This is what they took pictures from, with a camera equipped with a filter wheel.
hi marc! was going to point you to this video... nice to see you here. you both and also franblanche are my primetime! glad you know each other... thanks for your work. absolutely inspiring.
Hi Dave, and thanks for the blast from my past. I worked in the Calculator Products Division of HP in Loveland, Colorado when the 9845 was being designed. In fact, that I/O backplane board you first pulled out was my design, sort of. I didn't design the original, but when the systems tests of the 9845A had problems with DMA transfers to the external 9885 floppy drive, I was brought in to troubleshoot. The original backplane board had been laid out as a 2-layer board with no groundplane. During DMA transfers to the 98032A parallel I/O card that hooked to the floppy drive, there was enough switching noise to cause data glitches. I was given one board turn to fix the problem, so I had to take the board to six layers to get the ground and three power planes I needed to calm the noise. A few items: the LPU is the "Language Processor Unit," not "Logical Processor Unit." The 3-chip hybrid microprocessor is not optimized for Basic. It's based on the original HP 2100 minicomputer instruction set. A memory block switching IC was added to extend the memory in the 9845B. Chip-on-board technology with wire bonding (no flip chips) certainly existed and was used in 4-banger calculators of the day, but these HP NMOS chips dissipated too much power and needed the thermally-conductive ceramic substrates to carry the heat to the finned aluminum heat sink (also known as the Honda cylinder head). The ceramic capacitors are sitting on little ceramic beads (not ferrites) to prevent capacitor cracking during wave solder and against vibration. Circuit boards were all hand-loaded on a push line back then, so the women board stuffers (they were all women then) just slipped beads on the capacitors before they loaded the boards. Finally, these board designs were not hand taped. They were laid out with Bishop Graphics IC pads and colored pencils on large mylar sheets and then digitized on a large manual digitizer to create photomasks. We had to use 20 mil traces for long runs and had to neck down the traces to fit between IC pads.
Steven - thank you for the work you did and sharing this 👍
I'm chiming in with crowd ; I'm sure +mverdiell (Curious Marc) is positively drooling over your video at that very moment.
You bet. I am mopping the floor as we speak ;-)
I never really understood why Steve Wozniak wanted to stay at HP so badly until I've seen the engineering on this machine. It was truly amazing what those guys at HP were allowed to do.
@Drogo, Son Of Voltan The downside to that of course, is that engineers are very good at designing, building, tweaking and redesigning things... but given the chance, they will not stop. Nothing is ever finished, it can always be improved. They would never have a product to sell, or it would be so ludicrously expensive that nobody would buy it. Apparently some engineers don't even have the words "deadline" and "budget" in their vocabulary! 😉
@@another3997 "Ludicrously expensive" seems to be Apple's jam these days. At least compared to the PC market. And NOTHING Apple designs is made to be modular like this. Too much "idiot friendly."
@@BlackEpyon Nothing that crApple makes will still be in such good condition in 40 years time. Kudos to HP's old-school engineers who always put quality first
@Stuart Seeley Exactly. The REAL Hewlett-Packard. Dave nailed it when he said "made by engineers, for engineers." That's how they did everything until the stupid move into generic IBM PC clones in the 90s.
Dave, Curious Marc wants to know your location. Have you been following his resurrection of one of his 16-bit HP calculator/computers that took 12V up the clacker ?
Curious Marc has destroyed Dave's take-it-apart modus operandi. Now we want to see it fully restored and running like new.
is that mr FancyPants at 7:46?
Dave you forgot to mention @ 37:25 the ferrite transformers are bolted to the PCB using screws !! :D :D
You could send this computer to Curious Marc he will be happy a lot really and could revive it again
I love how it was designated to be opened and user serviced, a different time!
Those things were so critical (and so expensive) that most were probably under service contract to HP. Our local (Portland Oregon) HP sales/service office were equipped with the test gear, documentation, and access to replacement modules to keep their prime customers happy and productive. Certainly the plug-in modular construction allowed quick turnaround for repairs.
How many of us instantly thought of curiousmarc as soon as the video (or thumbnail) appeared?
Mr fancy pants would approve
Used I think the 9845A at the marine science labs located at Queenscliff in Victoria . That was around 1980 as my first professional job as a chemist. The unit was set up in a office on its own with a HP plotter / digitiser. Fantastic bit of kit at the time when most computer users were on CRT or teletype terminals connected to a minicomputer / mainframe elsewhere. The HP was used extensively to prepare and plot analysis results for water samples from Port Philip bay and Western Port bay. It was very popular and you had to reserve time on the equipment with the departments receptionist. More senior staff could be allocated long time blocks. All the HP lab equipment was the bees knees being well built, dependable, well supported and expensive.
Please please please donate this one to CuriousMarc!!!!
Yes. He and his mates are true masters of fixing these kind of HP computers. Just check out his fixing of his old HP 9825 czcams.com/users/CuriousMarcvideos
Totally agree. Then it is in very good hands as such beauty deserves.
Was going to post the same thing, marc needs to get this one
We need the brainpower and the dedication of Curious Marc to get this beauty to work again.
Curiousmarc would definitely approve of this beauty :)
That was my first thought as well
I'd love to know for how long he's collected hp branded chips. That chip collection is huge :)
We could see that hp basic in action. could get a fancy moment.
The HP-9845C, my absolute all-time favorite desktop computer. I spent some years developing research applications for anesthesiologists on one of these, and really appreciated the enhancements to the BASIC programming language (Matrix operations, to name just one).
Too bad you don't have the monitor. Agree that Curious Marc would be a good recipient for this, and would get it working in no time.
For fun, I wrote a program that "flew" you through the rings of Saturn, about one frame a second (and I just found the program, on folded thermal printer paper, barely legible, in my files).
The only thing that I've found that even comes close (and in some aspects, exceeds) is the Colour MaxiMite 2, a contemporary machine with much the same philosophy.
I used one of these starting in 1980. It was for lab data acquisition through an HP-IB module that plugged in the back. We wrote BASIC programs that processed the data and displayed the results on the screen/printer/plotter. It also had an option ROM with the FORTH programming language. I left that job in 1985, so I don't know how long it was in use after that.
I, too, used these in an electronics lab (primarily telecommunication equipment evaluations). Automated test beds, data analysis, etc. We noted at the time you could talk to a soup can with one of those.
Hi Dave
Thank you very much for showing me the inside of this machine. I just love vintage electronics and own a few pieces of equipment myself. At around 1989 when I was 13, I received this exact machine from a gentleman in my church that knew I had an interest in electronics and vintage equipment. I understood that the equipment was used at his work, but got replaced with newer ones. Mine is cosmetically still in very good condition. I also received a few external 8" floppy drives, a hard disk controller, plotter, printer, cables with plugs that fit inside the back of the computer, cassettes, 8" floppy disks, spare thermal paper rolls and other parts and documentation. The printer is huge, much bigger than the computer and monitor and it takes 2 people to carry it. Thank you very much for doing retro tear downs; they don't make them like this anymore. It's a work of art and you can see that people were still proud of their workmanship.
Kind regards.
Andre from South Africa
Wow! You can just FEEL the love and care the engineers put into that. Those little interlocking city scaped boards inside! Each board a bizarre 1977 vision of a future city. I honestly am very tempted to model each one of those boards up in 3D to print them and paint them. They are SO beautiful. SO much high art when into the making of everything. And the art deco circuit traces. Stunning. This gives me HUGE warm fuzzies. Inspired.
That's one hell of a machine...It deserves to live again.
I just choose to believe the caps are wearing leg warmers.
lol
It's from the late seventies after all... :P
For some reason HP used little ceramic beads on their caps so their beautiful legs would be protected and the coating would not chip off at the leg-body junction. Same beads that you’d use for hobby jewelry I believe. When you love your caps you don’t skimp!
@@CuriousMarc Let's be fair.
We all try to put a cap on our love. ;)
Kinda cute though lol.
Got to keep them warm haha
Geeeeeaarrrr!
Fraaaaaaaaaaaan!
How's the ET in the freezer doing?
Love how this popped up in my CZcams feed after 10 episodes on the curious Marc Episode. Love your Channel too Fran!
@@azzajohnson2123 check out cpu galaxy and adrian's digital basement as well, you wont be disappointed!!
This HP is from my time of working in electronics. This HP unit is a thing of beauty. Thanks for the walk down memory lane.
It is crazy how crisp and clear this video is! Good job!
Curiousmarc would Love this one Great Job'
Fantastic piece of vintage computer history, thanks for sharing!
I've seen a few people suggest sending this bad boy to CuriousMarc, however, I think you should try to find a monitor to complete this puppy and do an EEV restoration series of your own. recap and restore the power supply. Restore everything else, then turn it on... Show off how to use it! You've already taken it apart! :D
Dave, Thanks for showing us the inside of that bad boy. When I was in high school I had the opportunity to use an HP 9830A. I still have a couple of cassette tapes containing some programs I wrote and saved on that machine. Some day I may try reading those cassettes and see if I can decode the program/data on them. The list of ROM options was interesting. I saw it mention Advanced Programming, Structured Programming, and two for Assembly Language. You might be interested to watch the video series put out by Curious Marc where he repaired a 9825A that had a power supply failure that put out 13V on the 5V rail. Ouch.
From 1975 - 78 I was 'secretary' of my school computer club with access to the holy grail of the school's HP9821 (RPN) & HP9830 (BASIC) & TTY access to the cyber174 (FORTRAN) mainframe at Imperial College, London. I learnt to program on that 9830...
Overengineering is underrated. This thing looks like it was designed to go to the moon.
Not true. Over-engineering drives the cost up for next to zero realizable benefits.
It wasn't over engineering at the time. Those components were less reliable and more expensive than today. Also a lot of this gear had to go to the military market where drivers other than cost are more important
Not a chance. There's no way that boat anchor would meet weight requirements for a space launch. ;)
The AGC actually used wire wrap and discrete transistors.
Curious Marc will be interested in that item.
A lot of this late 70's early 80's HP stuff reminds me of the Xerox PARC stuff: Tech that was so bleeding edge that the guys who made it didn't realize just how advanced and ahead of their time they were. I wonder how far this architecture could have gone if HP adapted it to the general PC market instead of the high end workstation market.
In the late 1970s, I ran the "E-Test" lab in the development fab that where the 386 and Pentium were born. We had 6 or 8 of these beauties running automated wafer probing and testing. The I/O modules in the back were used for several things like HPIB (GPIB to the HP test instruments), and a local network (pre Ethernet), and 16-bit parallel Input/Output, etc. Those things really were work-horses and performed as beautifully as they look. Later in their life-span, they were connected to a networked 64MB hard drive which was 1/2 the size of a washing machine.
"E-Test" was where we took the test wafers from the process development fab and probed the various test patterns to close the loop on the various silicon process steps. Back in those days, the gate oxide was so thick you could judge the thickness by color with the naked eye. We had several hundred pieces of HP test gear throughout the lab, and the HP salesmen loved to bring customers to my lab as it was effectively an HP "showroom".
Several of the tests were ultra-sensitive (femtoAmps and femtoFarads) and had to be performed inside solid metal boxes (combination Faraday shield and light exclusion. And the manual probing stations were set on large air-bag vibration-isolation tables. Good times.
It was a brilliant machine. I used one in my first job after graduating. I started on a 9825 (in 1979) but when we got a 9845 (I can't remember if it was an A or B) a few years later I used it for a variety of engineering programmes including writing a circuit analysis program using complex matrices (that may have been an option for the HP Advanced Basic) but it made life a lot easier - you could just declare variables as complex and do matrix maths in simple statements. Not long after I got that running and plotting transistor and opamp frequency responses, we got an Olivetti PC and MicroCAP. My program was never used again! I still have the listing somewhere. The thermal printer was a 'line' printer, printing one row of dots at a time but it was fast! I have another printout dated 1/11/1984 that I wrote to calculate transformer, rectifier and filter capacitor requirements for power supplies. It looks as good as new and not faded as many thermal printouts do with age.
I worked at HP Ft. Collins where the 9845 was built. There was a "steamer option", I think it was option 200 that made the computer capable and fast. It was a bit slice processor set. Thanks for remembering this fantastic machine.
That was absolutely beautiful engineering. Right when I turned 20 and started into computers. Nothing built like that anymore.
Great video. I love those old HP all-in-one computer designs. I managed to get a new-in-box 9816S a few years ago. I had to find a ROM Basic board for it too, but it’s great for HP-IB programming. The HP-IB port is standard. It boots up in about a minute, and I can immediately start writing code, because the operating system is the programming language. I can quickly write and debug code to get the HP-IB functions I need working (even with modern test equipment). Then, if necessary, it also has a built in RS-232 port, so I can offload the code to a modern computer, and modify it for use in Python.
Designed and built in Fort Collins, Colorado. The HP facility is still there and is now mostly Keysight.
What a beautiful machine, people using it basically got a glimpse of what was to come just 5-6 years later, really awesome. Also, put those engineering details back in our computers!
Using the heat sinks as part of
the chasis is like a motorcycle
that uses the engine as part of
the frame. Such cool design.
Leg warmers for the ceramic caps.
Well, it was the 80's...
All older HP Servers and workstations are so well engineered.
a pity they've gone the same way as the others, market forces I know but it all seems to heading away from the innovation in engineering now
@@regmigrant have you had a look inside an HP Z Workstation? The engineering innovation is still there. Consumer grade stuff is crap, but their pro grade stuff is pretty remarkable.
@@TheSaltyExplorer thanks, good to know its not all doom and gloom
Just watched LGR and Techmoan, now this...its a vintage kind of day lol
Don't forget curiousmarc!
I had a HP-85 at work that came to collect data from an instrument. We added a printer and a dual 5 1/4 floppy drive, I wrote a data storage and reporting system for our lab to print reports. We used it for ~13 years! A great piece of hardware!
I used one of these when I was working in a semi factory. Yes, it was like US$14,000, I was told. That was terribly expensive because a brand new Toyota cost much less at that time. They let me use it to crunch statistical data collected from the production line. I remember I thought the demo was amazing because that was the first time I saw a computer drew a picture of a sail ship in full color.
In 1984 I have repaired hf transmitters and it was build on the same way. ITT JENNINGS and AEG Telefunken. Great stuff for advanced electronics.
Wow! You almost made me cry. Extremely nostalgic for me. I was fortunate enough to work for Hewlett Packard starting in 1984 doing field service. I got to work on several of these machines. Some times intimidating but always rewarding. Thank you so much for doing this review. Abe
The "MKnnnnnP" number is (at least as far as I read in a datasheet about the Mostek 3851 PSU and the 3870 MCU (Fairchild F8-series)) a reference number for the set of data programmed on the mask-ROM. And since each chip contains different data, they have different reference numbers for identification.
Paging CuriousMarc. Better treat that HP kit nicely!
Curious Marc's channel is where you ought to be heading. He is restoring a 9825 and he would kill for one like this.
Awesome! watching war games as a kid is what got me into computers/electronics, love that movie
At 7:08: “Correct me if I’m wrong down below, but the user had no way of actually writing, you know, machine language for this thing”.
At 28:00 - At the bottom of list: “Assembly Language Execution ROM” and “Assembly Execution and Development ROM”.
Yeah, noticed that on the last minute overlay. Other references said that users couldn't do it though. So maybe they didn't sell it?
16k Memory from 1980?! nice!
Could the comp go to some museum? i would love for something that gorgeous to be functional eventually.
Such olden design, superior in many aspects, looks far cleaner than modern PCB designs for example and the nerd rating of it is just off the roof .)
I'd love to play with one of these again! I worked on one for a year in 1984 or 85, had dual 8" floppy drives attached, and hardwired to an IBM mainframe so it worked as a terminal too. The thermal printer was amazing, I've still got printouts and plots that look as good as when they were printed.
Such memories, much wow! In the 9845B there was two different ROM-drawers, one on each side (one for Black labeled ROMs and the other fro Green labeled ROMs) that allowed one to extend the functionality with extra commands or capabilities. I used one of these with a Mass Storage Rom and an HP-IB Expansion card that allowed you to connect up to and control other equipment and also load and save programs and data to floppy disks instead of the tapes.
Looks like something that came out of CuriousMarc's basement. He loves this old HP stuff.
$14k because back in the late 70s, electronics were hand assembled. What a fabulous chunk of engineering and clever arrangement of things. Pretty remarkable, with no solidworks and just a drafting table with a straight edge and a pencil and such.
Basic was so much fun to learn on, object basic should exist for educating the next generation.
This was the first computer that ever entered my home, while my boss was on vacation for a week, back when I worked with one, back in 78 or 79, for a computer graphics research institute.
That machine has left a lasting impression on me that 40 years working with other computers have not been able to erase from my brain, as it was a very well thought out machine.
I loved your surprise when you discovered the ROM drawers!
Using a TI 99/4A as yr first example warmed my heart Dave.
And Dave is on the ropes, keepen up to Curious Marc. Still, great teardown.
My dad who was a brilliant Naval Architect was a master of this device. Many standards used by "Norske Veritas" and Lloyds of London regarding damage stability of ships were developed using this sort of machine and later converted. My dad had the model displayed in this video it had two 8 1/2" floppy drives and a harddrive (can't remember the specs but it was roughly the size your typical 12v RV cooler.
I used a 9830 at my summer job at HP around 1974. This later unit was around the time of the Prime 400, a general-purpose minicomputer with much better bang per buck. We used ADM3A terminals, and a shared line printer. Almost everything was still written in FORTRAN IV.
This needs a part 2. More vintage computer stuff please.
I remember these being advertised in the trade press (Computing Europe etc) in the mid 80s and drooling over them. I think they cost what was about 2 years wages for me at the time! Made me appreciate the Commodore PET I owned....
I'm gunna go out on a limb and say 20:55 4 GB memory support would be very unlikly in 1979... even by hard disc drives.
The first GB hard drive was created in 1980 and cost $40,000, almost 3x as much as the computer in the video cost. At a stretch, I could see huge companies maybe having four of those around. But unlikely. And certainly not in memory. 1GB didn't become common in a high end gaming PC until 2002ish. I don't imagine that even at the highest levels of university or tech giant computers would have had 4GB of memory 30 years earlier.
HP from this era loved their card edge connectors. I have just picked up a HP8640B sig gen that's loaded with gold cards and edge connectors
37:30 Sony's professional high-end cameras from the early 90s late 80s, they are close.
So are sony's CRT projectors.
Very easy to work on!
Most of Sony’s PowerHad SD ENG gear (
Yeah, ok, good call.
I'd even say that (mid to high-end) IBM rackmount servers from the 90's and early 2000's were as modular. I remember a service tech coming out and fixing a server for us and I was amazed he didn't have to use any tools except to open the outer case. The diagnostics on them were fantastic as well.
I worked using a HP 9836 in 1983, nobody had a clue how to use it, but I told a porky and told them I had used one before, (I'd seen one) and was taken on, on contract. Piece of cake.
"Engineering students take notes! What does this do? I don't know" - looks like you're inspecting something I would do heheheheh
Those power supply heatsinks are a thing of beauty
This is a beautiful example of mechanical engineering in the context of electronics. I see a number of high-rel/mil-spec characteristics to the design... definitely not your run-of-the-mill consumer product here. Great tear-down video!
CuriousMarc has triggered my interest in these old HP computers
I'm relatively certain that this was the system we had on one of the minesweepers I was aboard in the Persian Gulf from 1987 to 1991 - especially with the description of the dual bus at different speeds. It was for navigation in the minefields pre-GPS. Back stateside we had the horrific "PINS" system aboard the USS Pluck (MSO-464) that used an AN/UYK-44, and later I was exposed to the Zenith Z-248 (286 CPU, with cards on a backplane).
Awesome! I used this computer for my master’s thesis! Thanks!!
I'm a little older than Dave so I can remember that the HP 9845B was actually in competition with the DEC PDP 11-34 series. HP lost this competition of course, and DEC was eventually purchased by Compaq in the late 90s. HP purchased Compaq a few years later, so I guess you could argue HP won in the end...
HP didn't sell an assembler for it, but it could be done if you could talk them out of a copy of the instruction set docs.
Fiberglass substrate diebonding was done in watches.
This reminds me of early Compaq servers and HP server construction from the 90s through to early 2000s. The Compaqs were always built like a tank, and HP always strived on modularity.
I remember when we were using Compaq ProLiant servers as a step ladder to reach the higher shelves in the workshop - those things were incredibly solidly built :)
I bet Curious Marc would love this he repairs HP has a vast stock of parts ect
The serviceability of this machine is incredible for 79. Some real forward thinking people at HP were put on this project.
The guy who designed this is definitely a LEGO fan!
A lot of the best engineers are the ones who honed their skills on Lego :)
Just to clear up a bit of trivia... Colin Cantwell created the War Games graphics using a 9845C and HP Plotters connected via HPIB. The resolution of the CRT would not work on the big screen. Everything you see was first plotted in high resolution and photographed with various filters. As you can imagine this was a time consuming process. I'm pretty sure Colin still has a working 9854C in his archives. Plotters too, but the pens may have dried out by now.
Nice! Very similar to the Texas Instruments Silent 700 ASR terminals. I have one of those, built in 1974, last upgraded in 1983 by me. The wife wishes I didn't. Dual cassettes, *upgraded* acoustic coupler (300 baud!). Most of these devices have magic key sequences to put them in keyboard or cassette-upload programming mode, but firmware upgrades were typically done via EPROM swap.
Jeez, Louise! That thing is gorgeous. Imagine how many design man-hours went into that. Absolutely stunning.
I see HP with completely different eyes now. Impressive product.
Great stuff! Besides - any post mentioning WarGames gets my like! :)
I learned computers on the TRS-80, Model II! I'd love to see that teardown!
Those caps are so big, they could be a murder weapon in EE Cluedo (Clue) - "Dave Jones in the Lab with the Sprague capacitor"
Used this back in the late 70's/ early 80's for LCD engineering & test. Funny that only a few weeks after we decided not to extend the very expensive service contract, the machine smoked and died. Switched computers after that.
$14,000 in 1979 is worth $51,910.88 today
Wow! What a truly amazing piece of quality engineering! They don't build them like they used to, that's for sure!
This was the system that got me into computers in the late 70:s. We had one at work, an A model likely.
I programmed my first GPIB programs taking gyro drift data using two Fluke 8502As. I remember that one of the engineers wanted me to laminate some of my programs from the printer. First time they saw a thermal printer.
Hi Dave, regarding pronunciation of the capacitors - "Don't be vague, ask for Sprague!".
Exciting time for computers in the 80s
The green beads are not ferrite, but glass. They are there to elevate the caps slightly so that the resin on the legs do not interfere with soldering. Ie what your kid would use for a necklace.
I'd like to see the Tandy, I'm working on one right now
Yes!
I think some day we'll see a square heat sink tower that stacks in layers that includes cpu, video processor, RAM, to keep the connections ultra short and super fast and provide lots of cooling, modular, easy to u/g and maintain, easy to cool, and fast.
My recollection is the beads on the capacitors' leads are glass insulator beads (a.k.a., "INSULATOR BEAD GLASS", "BEADS INDIAN"), HP p/n 4330-0145. I'm unsure why they were used. My guess is the beads mitigated heat transfer and mitigated molten solder wicking all the way up to the base of the capacitor during PCB manufacturing (specifically, during the solder bath process). Perhaps they didn't want to use formed leads on the caps for this purpose, as the longer lead length would've added unwanted inductance to these bypass caps, and perhaps some unwanted EMR.
Glass beads to space the bottoms of the ceramic capacitors off the board, so that they would all be a consistent height, and also to prevent the dipped capacitor having stress on the dip line from the board, which could pass stress through to the capacitor, and cause the ceramic to crack. Seen this on military equipment, though there they needed that tiny little bit of space, because they use the flat pack versions of the chips, so the beads were replaced with 1mm hole diameter PTFE circular spacers, that served the same function. Others, where the ceramic capacitors were too high, simply had them with a bend in the lead 2mm from the body, and then the capacitor flat on the board, held there with the conformal coat. Cost you board space, but made the component side essentially 5mm at max, so the next card was 6mm away.
Must have made assembly be all hand, as you would need to put the beads on each capacitor, and i noticed the use of at least 2 colours, green and white, so they likely were buying them off of a craft centre near them for the production runs. Even had one with a green on one lead, and white on another, likely the green and white glass beads were the cheapest ones that had a hole large enough, being a colour least favoured for bead work.
Love the heat sink on the rectifier. I want one