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The mystery is solved Let's repair the 8-bit guy "Found at Computer Reset" IBM Executive Workstation
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- Опубликовано: 23 апр 2022
- The famous Prototype IBM Executive Workstation 7496.
Let's repair it and solve the mystery.
The famous "found at computer reset" video: • Found at Computer Rese...
New on Twitter, Thanks for sharing and supporting the channel: / epictronics1
My aunt was a marketing executive at the IBM campus in Saint Petersburg, Florida (USA). Although she does not recall this model in particular, she does recall that at about the time these units were being produced that a variety of models in small numbers (less than 100 units each) were put together to be given to various "corporate customers" for on-site testing. The feedback her department received from the "corporate customers" was then used to shape a prototype targeted for use at counters in transportation, hospitality, medical, etc. She remarked rather bitterly that even though feedback had indicated significant interest by airlines and hotels, higher powers decided to move in the direction of a more generalized system (I am guessing that would be some iteration of the PS/2, she didn't say).
Thanks for sharing. That's very interesting. I was not aware of these 'marketing machines'. These 7496's could totally be a part of them. There is a big demand in the community for info about these 7496's. If she has more to share it would be very welcomed.
@UCOet9cU6_StydNTftV3y0qQ Yea, I think this is the most likely explanation so far. I hope we can get more info about these on-site testing machines
@@Epictronics1 It does seem to fit. A product meant for a counter much like point of sale kiosks would make a lot of sense. If it was a marketing test it sounds like they didn't fill the demand needed to sell such a similar product to something IBM already offered. I speculate they would have sent out one of those surveys that asked how much they expected a product would cost and it all fell well under the target IBM was going for so they opted for another product or went back to the drawing board. I could be wrong of course but it does seem to fill in all the gaps.
@@Carikenja Yes, Marketing machines is the most likely explanation so far. The most expensive CRT on the market put on top of the base range MOBO and a slick but poorly designed custom case. Sounds like marketing to me.
@@Epictronics1 The CRT might have RETAILED at a high price, but IBM probably could buy them in bulk at a much lower price, enabling a mid-priced ( though really IBM should make its money out of support contracts on top ) item overall. Looks like it was designed to compete with some of the remnants of DEC / NEC/NCR Terminals offering more functionality so a company could standardise its computer inventory instead of having little POS amber screen dump terminals, or those linked to other central computer systems solely. As we know the progress of the computer hardware at the time was so fast that designs became redundant almost before they were produced in reality. IBM of course also found that the software part of things had become so key , and they were out of that, such that the attempts to value engineer products as hardware for the mass market was becoming not worth doing. You can see why the products were dumped into the computer clearence guys (in the UK we had Morgan Computer retailing basically crap at just below better in the market prices, i got burned a couple of times trying to get items bought in working gave up and ordered Dell PCs and Panasonic Laptops.
Nice to see a wrong be righted. It's definitely a weird little machine, and it's interesting to see an "unpolished" IBM product since they were usually so well-built and engineered.
Its not the exact machine, David was working on.
This video scratches an itch I've had ever since Murray's disaster of a showcase - great to see one of these taken proper care of. Thank you for making this, and I'm glad RUclips put it on my feed.
Thanks :)
lolololol paperclip go boooom 😂😂
@@kami-kun_va The Dremel was an even worse choice.
Why you gotta do the one-byte man like that?
The Executive Workstation was also listed in the 1993 Computer Reset catalog with a price of $599.
Interesting. I wonder if Richard ever sold any of these. Maybe these five were unsold because they were broken and unsellable
@Epictronics A friend in NY has at least one of these, I don’t know if he got his from CR.
@@compu85 Would you mind asking him where he got it and if he knows anything about these machines? He might know something interesting.
@@Epictronics1 I asked and he got his from Computer Reset too.
@@compu85 Interesting. So, CR is still the only source so far. If you don't mind, we would be interested to know if it was from the liquidation or if he bought it from Richard back in the day and if it was working when he got it. Thanks
When you said there was something loose in the box I thought it was a joke and you were going to pull out a paper clip. 😆
I actually recorded me pulling out a clip from the machine as a joke but decided to skip the joke in the edit :)
@@Epictronics1 I think I have a few monitors that need cases unscrewing , seem to be all kinds of loose bits moving about.
@@Epictronics1 honestly, I don't really blame the 8-Bit Guy personally for the paperclip fiasco, especially since it is actually a technique used for testing even modern power supplies without installing them in a system (EVGA guide: ruclips.net/video/buPMx9dw0LU/видео.html), I personally just wish he wasn't under so much time crunch that he wasn't able to properly investigate and realize that doing that would have been a bad idea for that particular power supply, and also have time to get a proper bit to remove that fastener.
@@highpath4776 haha, well, same here actually. But in this particular case I think it was wise to avoid any risks
Hi, MCGA supports 15khz output, which that Sony monitor appears to require. Normal VGA cards output 31khz, so the VGA signal isn't compatible.
It all means it would be possible to use a Commodore 1084 with any MCGA machine, or use that Sony monitor on an Amiga or other 15khz machine.
Two bad custom chips seems pretty bad! Luckily it's just a normal Model 30 board otherwise it would have never worked...
Thanks Adrian. I couldn't find anything while searching for this SONY CPD 9090. However, it also says CPD 9000 at the back, so I think this is a 9000 with some minor change. Perhaps the adaptation for the 7496?. The Operating instructions online (linked) confirms your guess. This CRT seems to have been mainly designed for the Sony SMC-70 Microcomputer. Sony were also offering cables for that funky Honda? connector at the back to PC/XT and even the proprietary PCjr :) A really cool CRT, a treat all by itself. www.manualslib.com/manual/242746/Sony-Cpd-9000-Operating-Instructions-Primary-Manual.html
I think the built-in Sony monitor was rolling when connected to the VGA card because it was designed only for 60 Hz refresh rate, while standard VGA text mode is 70 Hz. If the horizontal scan frequency was different, the image wouldn't be legible, and the IBM VGA monitor wouldn't produce a legible image when connected to the 7496's onboard video, either.
You can also see how the Sony monitor has no visible flicker on a 30 fps camera when using the onboard video, so that proves it's operating at 60 Hz, versus the flickery image produced by VGA's 70 Hz mode.
@@Epictronics1 that's right. That connector is the EIJ-8 I think. I just ended up with a Panasonic TV with it as well. (From 1984) Usually it's digital RGB only, like CGA, but sometimes it supports analog like the one you have there. And indeed, confirmed in the manual, it's only 15khz, so basically exactly the same RGB support as a Commodore 1084. Basically it can only display PAL and NTSC frequency RGB video. Luckily MCGA can do that, unlike the VGA adapters. That's the CGA part of MCGA as CGA is 15khz. It just changes from digital TTL 16 colors to analog RGB to support a wide color palette we are all familiar with. MCGA also supports VGA output resolutions like 640*400*70hz for text mode which is why your IBM VGA monitor worked. (That other IBM monitor only supports 31khz and up, not 15khz)
@@vwestlife When looking at the rolling screen I can see two copies squished side by side. This suggests the external card was outputting two lines of signal for every line physically scanned by the monitor. Sync circuits are usually happy to semi-stably lock on if the signal is mathematically related to what it is supposed to be.
As Adrian said the MCGA also can do high resolution text modes and I presume the ID pins on the connector tell it what scanrates to use. Which just leaves one question for me. MCGA supports 1-bit monochrome 640x480. What happens if software sets this mode when the 15kHz monitor is connected?
@@eDoc2020 The solution is to connect it to an LCD monitor with an information display that tells you the horizontal and vertical frequencies of the input signal. Then you'll know for sure.
Great repair, well done. And awesome to see this rare machine back up and running.
Thanks :)
Great video and a nice continuation to where The 8-bit Guy left off. However, I'll never get the words "bloody nut" out of my head now without some improper imagery.
Thanks
Great video! One quick trick for Deoxit: I always spray it into a small plastic squeezable bottle to use as an applicator. Much more controllable and less waste - lasts a lot longer that way too!
Thanks, I'll try it out :)
The box for your unit unfortunately was water damaged and cut up to the point where it wasn't even worth keeping around, so the boxes were swapped.
I see. Thanks. It sure helped for a safe shipping :)
This was incredibly satisfying. This is the love that workstation deserved. He did a decent job of frying that board. Without replacement chips there was no fix here.
Thank you, glad you liked the video :)
SMH at all this 8 bit guy hate in the comments. I don't see you all trying to fix an old machine with no manual.
Totally agree. The 8-bit guy is a good lad and I like his videos.
That keyboard brings back memories. The feel, the sounds, the pure excitement of typing DOS commands back in the day...
There's nothing quite like the Model M.
David is so haphazard in everything he does,, thank you for doing this right.
Couldn't even send all the screws.
Everything? Seems a bit dramatic. The immense amount of hate he's received for a single screwup seems ridiculous to me
@@Evan2what about his "drean computer" project that came out as a completely different product that wasn't even close
Thank you for taking the time to repair this computer.
Wow! 😮 your skills are simply amazing. So satisfying to see repairs at that level!
Oh man I remember the utter shitshow that was the comment section on the 8-bit guy's video! Some backlash was entirely justified, but as always the comment section went above and beyond...
It was nuked not 14hours later too, it was crazy lol
I love these disassembly/repair videos. While you were dealing with old solder and stubborn chips, I wondered if you have used any of the low-temp/smd-removal alloys? If you have, what was your experience? If not, why not try? It can clump up, admittedly, but as a novice yet with the hot air rework, I find it works well and I do much less heat damage from the hot air. Also, I agree that soldering the SOIC packages by hand is a pain. Seriously, interested in hearing about your experiences.
Thanks. No, I have not tried it yet. I will do at some point I'm sure. I think Dave Jones made a good video using it a while back.
Please keep it functional! It's a really beautiful machine. I learned how to do the bolt mod myself last year when I purchased a virgin IBM 5170 with its original keyboard on eBay.
Great video and great repair! Restoring such a rare machine takes great experience and confidence. You are a true master! Enjoyed every second watching somebody who knows what he does :)
Thank you :)
Glad to see this device get some love and attention it deserved.
Thanks :)
When I saw that this video is nearly 53 minutes long, I was not sure if I would have time to watch it all, but in the end was glued to the whole epic episode the whole way through. It is so satisfying to see the wrong righted after the original paperclip and Dremel disaster.
Thanks, I'm glad you liked it :)
wow, didnt expect to see this machine ever again, very cool
Thanks :) It's alive! I'll make a second video and we'll just play around with it for bit and have some fun
@@Epictronics1 thats very good to hear
Oh, thank goodness, someone fixed the gun nut's mistake.
The gun nut?
This was not the 8-bit Guy's PC, the security screws were not a Philips head :D same type of computer, anyway. Thanks for the rare find.
This is the second PC in the 8-bit guys video. It's the one with garbled screen
wait... i didn't even realize david disabled comments on the original video... guess people were just being asshats...
but im glad to see someone doing this thing justice
he disabled comments like 5 or 6 days after the video was uploaded
I feel I was the first person to scold 8-bit guy.. however, he could have been deleting comments before mine.. too bad the comments were turned off.. engagement if engagement.
I’m curious what did you scold him for exactly? I too feel like that video was somehow not thought about much
Wow! Seems this prototype of IBM desktop been fixed and finally works! I hope 8 bit guy would know about your video and pretty excited about fixing stuff! 💪💪
Yes, he joined the live chat
@@Epictronics1 Excellent! I bet David would very happy with you for resurrect this prototype like IBM 7496. 😁
This prototype isn't an unreleased device like beta testing?
@@BillyRazOr2011 Well, nobody seems to know what they are really. There are several theories but so far there is no documents or pictures to support any of them.
@@Epictronics1 Oh... That's pretty unfortunate. But I hope someone would know about that device for rare documentation.
First of love your content and videos as always. Some of the comments here are insane. It’s easy to scold (hilarious terminology likes he’s a child) a guy for messing up. You know he didn’t have to show that he messed up he did it to show everyone makes mistakes. But the people who commented on this situation seem to think they would never make a mistake and that no one else ever should either. Most of these jokers have never and will never have access to such cool computers or equipment And if you think you can do better make your own channel ( let me know how that works out for you Monday armchair quarterbacks) using a paper clip maybe didn’t work in his situation but it’s not that insane to do. We all have done a paper clip job to say use two power supplies with one system or for experimenting. I’m glad that the 8bit guy was honest about his work and showed it all good or bad and I’m glad Epictronics saw a opportunity to fix such a pc for those of us who wanted to see that model working and fixed. RUclips and electronics communities benefit from both types of tech enthusiasts.
That computer has paperclip PTSD
It was some time since i enjoyed watching something on youtube as this repair, happy that you got your hands on it :)
Thank you :)
I suppose they were meant to be on the desks of executives, where the reduced physical size would've been desirable. Nice fixing anyway. I wonder what made both those chips go bad.
Yea, that makes sens. Piles of cash take up a lot of space. Perfect with a smal 7496 on the desk haha. I'm starting to think that something zapped this board. I did some more testing with the floppy controller and it turned out marginal too. Thank you :)
Some chips encounter flaws during the manufacturing process, and eventually fail over time. Some were more susceptible to ESD. I forgot what the pass/ fail rate was common for that period, but IC's are much more reliable these days.
@@timmooney7528 I agree. I have piles of commodores with dead MOS chips and a few clones with failed IC's. But this is my first encounter with dead custom IBM chips.
@@Epictronics1 when you say "something" was this "something" called David? :P
Could be metal migration, a slow death that occurs over time, totally unrelated to usage hours, ie stock kept on shelves for years never works when taken out for use.
I'll say it again since the comments are turned off on the original vid... it's not a prototype. It's an RPL client for IBM Server Manager networks. They were sold for institutional settings and use a floppy to then bootstrap off the network. See: en.m.wikipedia.org/wiki/Remote_Initial_Program_Load
Such a cute little machine. It reminds me a lot of an old Data General Dasher One I had.
So awesome to finally see one working, you did a great job!
Thank you :)
Never thought I'd see this video. That video with 8-bit guy along with that ridiculous AI video he did lost him a good number of fans. Glad you're able to revisit the legendary IBM workstation.
I'm not familiar with the video you mentioned. Do you have a link or video title?
m.ruclips.net/video/Wh2OCBZpzZ8/видео.html
@@stevecarr32 ruclips.net/video/BXqjoTkyFXw/видео.html
This is a re-upload of the ai video as he took it down. His IBM workstation video is still easy to find (but with comments disabled)
From what I can tell, in the 80s J1 was Lexington, KY. The plant numbers have changed over time and J1 later refers to Raleigh, NC. It's not clear when this change happened, but at least in 2001 J1 referred to Raleigh. But it's safe to say that J1 for this 1988 Model M almost certainly refers to the Lexington, KY location.
Thanks!
I am surprised how many screws were missing from the previous repair attempt 🤔
I never fit back the same number as come out.
lol
when removing an IC like that, I have found that it's not good to apply heat as you remove because it reflows the solder and makes it stick again in some spots. in my experience, it's best to free the pins by wiggling them while hot with the desoldering gun, and then ensuring they are free afterwards by making sure they still move when cold.
This was so great, awesome job fixing this! So these mysterious machines do actually work after all...
Check for paperclips!
No paperclips were harmed in the production of this video
Awesome video! Super cool to see what was wrong with that machine after the 8 bit guy passed on it.
Thank you :)
on beta hardware, this is why many companies socketed any chips the could, back in the day some production units used socketed chips like this because it was the best way to avoid replacing whole boards/cards on very expensive cards/boards/systems over chip failures or defects.
I had visions of Gene Hackman in “The Conversation” ripping his apartment to pieces looking for that nut. Great teardown video
lol, thanks
"I can't take any risks here, i really don't want to damage this machine" - not the 8-Bit Guy
Well, to be fair. I do misstakes too.
@@Epictronics1 Everyone can make mistakes.
@@MidoseitoAkage Totally agree
I will "just" put back the chips I've used to repair this machine back to their original systems..... I would consider myself blessed if I was only able to replace ONE surface mount chip in a vintage machine without killing the whole thing. You surely have a lot of meticulousness and patience to do this stuff, big thump up for your work!
Thank you :)
It’s good that 8-but guy made that video so these machines would get some attention. Love to see it.
Totally agree. I wouldn't know to ask for it if it wasn't for David
@@Epictronics1 loved seeing the time and attention to detail in this video. You can tell that you really care about the machine and respect it’s history. I would love to know more about this one and why it was made. We may never really know. Thanks again.
@@Epictronics1 Oh dang. Thanks, I planned on digging through your channel later anyway but this is great.
@@rphntw1n Thanks :)
Love to see this being worked on by a competent technician!
Thank you :)
That video with David was the one that made me start questioning him being a good guy. Now I believe he will do anything for money.
Considering the age & degree of trouble with this machine, I am impressed with your very thorough repair. Your should consider putting-on a Master Class, for circuit board troubleshooting & repair. :)
Thanks :) But I'm still learning :)
Man I love your technique and te quality of your 📹 video recording .and everything is so clean. I had a issue with your accent so I have to re-watch some parts. Great video and work .awesome job with that pc
Thanks :) My english is a mess. No wonder
@@Epictronics1 the English was fine, just it's like you forces the words. With some practice will be fine. Sounds like the south part of USA. Sorry 🙏 I shouldn't judge you, probably would have a similar issue. But I think you have great videos so I try to help. Just relax the throat.
Excellent work! Glad you saved it!
Thank you :)
holly crap you got a steady hand! beautiful work!!!!
Thank you
i need to make sure i understand. this isn't the device david blew up with a paper clip, is that right? that one's dead and gone. this is the second device they gave him that he ended up returning.
No, The new owner of "Clippy" has commented below. That machine will be repaired too. Yes, this is the second unit in that video. The one with skewed text that they were tinkering with on Texelec's kitchen table.
it's not a "device", it's a computer.
@@Epictronics1 thanks for clearing that up. i'm glad you saw that comment because i haven't found it, but i trust you. very good news to hear that one will be fixed as well, i trust it'll make my feed in good time.
@@staticfanatic I don't think he will make a video. Not that I'm aware of at least.
Damn I didn't know Dracula made RUclips videos, awesome 😎
Cross between Dracula and Christopher Walken. 😂
this video needs more dremels and paperclips
Maybe needed 2 paperclips?
I don't know man. I'll have to install Office 97 and ask Clippy😁
twice the fireworks😭
no common thief would steal this as its obviously not going to run Crysis.. so it narrows the list of suspects
Caution! Dont burn! Hahaha
It could also be IBM's approach to convenience store's/cashier clerk computers
Yea, that would explain the choice of the full size model M with the numpad. It looks absolutely huge and out of place with this tiny IBM. I also forgot to mention in the video that it has a cable duct under the unit. It's however to small for the standard model M cable. They were probably considering a straight cable with this project.
Best to keep it civil 😆
The chip connected to the FDC is probably a VFO (or data separator) equivalent to the SED9420 chip, it compensates for small timing deviations from the drive with a PLL circuit.
I think the FDC IBM chip may well be the same pin out as the Chips and Technology 82C607 as the datasheet claims its an IBM PS/2 compatible clone chip to interface the NEC D765A FDC to PS2 systems. The 82C607 is a port decoder chip to decode IO 037x to CS RD WR etc for the D765A. It also includes the data separator analog and digital circuits that sit between the D765 and the drive. I have what I think is a failed 82C607 on a PS2 clone machine from 1988 which isnt decoding the IO addresses correctly and is failing to CS the D765A chip. I'm awaiting a replacement 82C607 to arrive from the US. The 82C607 data sheet is available as part of the CHIPS/250 chipset.
Interesting. Let us know how it goes, Thanks for sharing
Great job!
Thanks :)
Now this could be amazing. I'll let David from the 8-bit guy post a Update video that the machine is working.
Excellent Video, Thank you 🙂
Thanks! : )
I bet that screw driver with changeable tips will fit right on those standoffs. Easier to use a screwdriver safely on those than adjustable wrench.
I have a set of screw drivers for bolt head screws but these standoffs were unusually large.
Big like for not yanking the smd caps off the board! Great video!
Thanks!
@@Epictronics1 and I just watched the 8bit guy video: another virtual like for not opening the PSU with a Dremel………. Sigh!
I came for vintage computer repair but I stayed for the Christopher Walken-esque narration. My only criticism is that the video needs more cowbell.
Haha, thanks :)
Thanks for sharing. 😉👌🏻
Awesome video. Great to see come creative troubleshooting using a donor PS/2 to get the right result.
Thanks :)
If my memory serves correctly, the earliest of Model M keyboards were made in Lexington, KY, and had plant code J1. So, if i were to guess, that one was made there.
Genuine question, are people still mad at The 8-Bit Guy about what happened?
I don’t know. Stuff is junk anyways. People acting like it’s the Apple 1.
i can hear that your desoldering station is still running its fan off of the same supply as used for the pump.
I'm anxiously awaiting this...
Nothing to be anxious about David. I fixed it with a paper clip in minutes! hahaha
The paper clip needs to be precisely calibrated
@@Epictronics1 Is there an IBM part number for the paper clip ;-)
@@AndyGoth111 Yea, I had to go through a whole box to find one that fits perfectly : )
@@MySmartHomeDomain Yes, they are FRU 472506. I found them here: www.staples.com/Staples-Jumbo-Paper-Clips-Smooth-1-000-Pack/product_472506
There are amateurs and there are pros. This guy is definitely a Pro, with a capital "P".
Thank you :)
The design was probably IBM's answer to the Apple 2c and 2c+, trying to appeal to the trendy executives who didn't wear neck ties
I have the IIc lined up for a video. Let's get trendy like it's 1984 :)
Even though i didn't watch the video in full, I hope you've attempted to convince David to get an iFixit toolkit (Pro Tech Toolkit or larger) so he wouldn't cut screws again!
Or he can save money and cut screws.
I actually feel bad for Dave getting all that hassle over his not so thought out repair attempt on this machine( it was bone headed for sure and I said as much in the comments section). However..... you know.... we've all made mistakes. Let's lay off Mr. Murray and realize he does offer some very good content 99% of the time.
I totally agree. I hope it's clear in my video and in my comments. I think David is a good lad and I enjoy his videos.
Given these 2 custom chips are found in other IBM computers of that era, I suggest you leave the executive as is and try and source another donor to fix where these came from. This will put less stress on both the working ICs as well as the underlying PCB in the excutive.
That is a very good option but I have been offered a spare board specifically for this machine. I would have to source another model 30 board to leave those chips in there.
I'm a early user of IBM pc (in 1981-82, yes i'm old), and IBM, in those years and later, oftenly use flat head screw in their pc's (1 slot screws). I've allways hate that!
Yes, I'm lucky enough to have a collection of 80's IBM's and they sure have flat head screws. However, they all have combined bolt head/flat head screws unlike this machine.
missing corners are usually gone. Otherwise they would not be missing.
I have been waiting for this comment for six months lol. I was wondering why nobody had remarked on that silly mistake. I guess people are very polite on YT : )
You fixed it!
New subscriber!
:)
You are one... Wild and crazy guy!
If the thieves are anything like me, they steal the machines, fix them up and put them back. Been there done that (sorta - it was e-waste and I live in Germany. Taking e-waste, even from the curb, is considered theft here)
That is so strange. All vintage computers should be saved. I'll talk to Germany and sort this out
I'm confused, I didn't see a paperclip used in any part of this video? Was it done offscreen?
Yes, I had to use it off camera to keep the trolls away from the comment section.
first time i watched this channel, I admire your skill.. im probably one of untold millions thats said you sound awesomely kind of almost like picard at times, love it :)
haha, Thank you :) Well my voice is commented quite a bit in different ways.
awesome video. makes me interested in everything else you have done, subbed!
Thanks :)
He did nothing wrong, he did everything correct.
@@jettesides420 Thanks :)
He came to stare at this rare machine and made an amazing repair.
Thanks :)
TBH Not really. Just replaced chips on it and did some repairs. Now, actually following and fixing, say, broken solder joints (like David has done in many of his videos) IMO is the next level, taking a boards and device with damaged traces and bringing them back to life. Soldering new capacitors and resistors is not a terribly difficult job. Replacing chips is a bit harder, but not impossible for most people with a steady hand and an understanding of electronics. But broken traces, especially ones that are not easily visible, takes more patience, and trouble shooting, as well as full knowledge of how the board works and how things interact.
These so remind me of a pile of PC's we had at a telco,
Single floppy drive, locked away from the user.
They were used as mainframe computer terminals, you just turned them on and they booted up with terminal software, and that was that.
They were a darn sight cheaper than dedicated terminals, so we had quite a few for our various offices.
Having the drive locked away ensured they were not fiddled with by the users, they just did their intended jobs.
I'm currently having fun with retro computing, the type that uses terminals, these would be ideal, pity there is so few, on the wrong side of the planet to me.
Cool. Do you have any old pictures from the office? We'd love to see those machines in action.
@@Epictronics1 We were not using these exact machines, ours were low profile clones, the floppy drives were mounted back as far as possible, with the normal blanking plate installed in the front covers, so the drives were hidden. You had to pull the plastic case front panel off to access the drive.
Otherwise they were boring under-powered white/beige boxes with no apparent drives installed (kind of like a modern gaming PC, blank front, no drives)
I think most of ours ran mono screens, maybe that's why the IBM 7496 was called 'executive' because it had that Sony colour screen.
@@paulstubbs7678 I think they sound like cool machines :) I'd love to hack one of those clones to make them do something fun. Well, there was one Executive with a PS/2 CRT on top. Unfortunately it was snatched from CR so we don't know much about it. But the common guess is that it was mono.
35:13 ah yes, those quirky Alps PS/2 floppy drives, Toshiba PS/2 drives are more reliable but also expensier. I literally salvaged two from a beyond repair ibm convertible to use them on a model 25 with Those freaking Alps drives, leaking caps destroyed the Motor controller on both.
I was longing for the sequel to the 8-bit guy's paperclip operation 😁
Hope you enjoyed it :)
@@Epictronics1 Yes, it was really a great video. The shots are at a perfect angle. If I may suggest something, add some background music.
37:47 - That double triangle logo is Seiko Epson, so must be some custom gate array device they fabricated for IBM.
Thanks!
Was watching Knight Rider 2000, and saw one of these computers in the scene where the cop helping Michael Knight is in the mainframe room.
Really? Are you absolutely sure? I would have to watch it if you are sure it's one of these
@@Epictronics1 about 90% the picture is from the side.
@@jeriks7894 Ok, I'll watch the movie. Thanks
@@jeriks7894 Hmm.. It doesn't seem to be available online. Anyone who has it, please check.
I had a ps2 that belonged to the place I worked at.
This looks very much like the Sony monitor wasn't able to display the graphics card's vertical frequency which is exceeding the Sony's capabilities, but it might also be some alternative sync signal pinout, like combined sync.
Thanks, there might be a spec sheet out there. I'll try to find it now that we know what it is.
It turned out to be a 15khz CRT. The onboard MCGA can do that and VGA!
@@Epictronics1 Oh, interesting, thanks! So the CRT can't display 80 columns or just interlaced?
@@elmariachi5133 It can't take the 31khz from the VGA card. It can only take 15khz from MCGA and other machines with 15khz.
@@Epictronics1 Yes. 15kHz usually means incompatibility with flicker free high resolution signals, like the older Amigas, that's what I was wondering about.
Fascinating stuff!
One thing I noticed is that you insert the boot floppy before you turn on the machine. I always thought inserting a floppy into the drive before POST risked damaging the disk so I usually wait until I hear the heads move and then insert the floppy (or in case of a 5 1/4" close the drive). Is that an old wives' tale or is there anything to that fear?
Thanks. I have never heard this before :)
@@Epictronics1 that might have been the case on early controllers if the heads rest state were lower down then moved after start up.
Certainly with the 8-bit micros I had, the manual said not to turn the power on or off with a floppy in the drive - I think the thought was that as the power surged on or faded out it might cause the read-write head to erase the data on whatever part of the disk it was sitting on.
@@john_amend_all Interesting. I had completely missed this
Great work! Well done!!
Thanks!
Epic repair! Subscribed
Thanks :)
What about putting the PLCC chips into sockets, too? Aren't they easier to solder than resoldering the chips?
Yea, why not. That would totally make sens. I'll consider it for the next swap. They are not easier to solder but it will be easier to swap chips in future testing and trouble shooting.
just don't noticed where you got the spare PLCC custom chips from
@@Mr1X They are borrowed from two other working PS/2 systems. IBM used these chips in several other machines.