Congrats! Tape data loading onto the drum! That’s quite an achievement. It’s really neat to see the data build up on the track at the pokey speed it’s read in from the tape. Such a relaxing computing pace.
Thank you! Interestingly, what we're seeing on the scope is incrementing four words at a time, so that's actually 116-bits being transferred over at a time, which is decently fast!
As a highway engineer, even my modern computing equipment often struggles with road grading terrain models and leaves me pulling my hair out (Microsoft + Autodesk + Bentley is a recipe for chronic ulcers) so I have all the more appreciation this thing was doing it (probably more reliably) 70 years ago.
You have the best ability to convey complex computer jargon that I could never understand on my own. I appreciate you saving historical items like this and sharing. Many thanks. Always enjoy watching you.
Thank you so much! The G15 is quite a complex system, even something as simple as loading in paper tape data is a fairly difficult system to understand, so I definitely wanted to take the time and explain it as clearly as I could!
@@UsagiElectric I assume it helps a lot that you are familiar with both the principles of operation for vacuum tubes and already designed and built a small, primitive computer with them.
Unfortunately it can't. I spoke with David when he was at Systems Source removing the good drum from the Bendix they have on display. I said the very same thing, "I cant wait for it to print out 'Hellorld'." David said it cant, since the Bendix is a numerical computer only. It can't do alphanumerics. Therefore no letters. The closest he could get would be printing images of the Hellorld letters. I hope he can get that far.
I am 62 years old. Despite that fact, I have experience with a Mach 3 computer, which of course had tubes. In particular, I did a binary add with the adder circuit of one, back in the late 70s. It was interesting as the "accumulator", a set of neon bulbs, changed with every bit change of the additives., two sets of switches. It had hundreds of tubes, and was very bright and took a while to warm up, I am pretty sure just the adder circuit ran thousands of watts.
That single scope shot made the entire input system click in my head and really helped me understand what was going on! Also, it was just super cool to see the data push around the drum line!
First let me say: Lloyd, you are a bloody legendary hero to keep coming to restore this old beast from your working days back to life and we totally appreciate you! Grats Dave! PLEASE keep focus on this machine until it's 100% rather then cycling through projects if possible (and if Lloyd's schedule allows) because it's SO close I am all but dancing on my toe-tips here. I cannot believe how invested i've gotten into seeing the Bendix run, it's worse then with the Centurion that got me hooked on your channel in the first place, LOL.
He does need to wait on other people too, plus he needs to get some mental breaks to work on something else or this thing can burn him out a bit. I'm glad it's getting more attention lately, though! Bendix is like the new Centurion, the big project, and after that we can get on with a new big overarching project while the others get to be the fresh air between.
Lloyd is absolutely a legend! I have a trip planned to Pittsburgh coming up in about two and a half weeks, so the Bendix will be on hold during that trip, but I am going to try to get another episode in before I go. I think the very next episode might be on the diode tester since I'm quite amped up about where we are on it!
Absolutely fantastic. I was quite Skeptical that it would ever live again, "Bit more then you could chew" type of thing. But you and the community has shown, there is bite to that bark. I am in awe!
Fascinating. For some reason RUclips dropped this in my feed. It’s wholly unrelated to anything Ive ever watched (unless restoring old tractors and boats is a connection…) So naturally I didn’t understand a word you said but still found it mesmerizing that a machine like this could show signs of life and that you know how to coax it to function.
It is awesome that you (and your expert helpers) are able to diagnose such a complicated machine, and get it working. I saw the episode after this one before watching this one. MTBF gets you after decades...
Seeing the blocks of bits march across the scope as they were shifted onto the number track gave me goosebumps. It's incredible that you've even gotten this far on a machine that is pushing 70 years old! You're a restoration legend, and Lloyd is too for contributing his first-hand experience with this machine! I can't wait for the next video.
I remember these machines well! Stacked Winchester drives, punched tapes and cards, readers. The main sections of the entire computer like the arithmetic, analog, digital and tape drives were mounted in 19" racks about six feet tall.
Lloyd is an absolute legend. And so is this machine and your videos. Love the passion for old machines. It means they'll continue to operate for decades to come so long as people stay interested in them.
That's incredible. What a beautiful machine. Nice job getting this far. And I know what a mammoth task it was just to film and present this video. Thanks!
Back in the 80's I worked for a large photocopier company and ( starts with X ) was sent to a month-long training course on one of our large production machines. This was my introduction to computer logic and this machine was discrete component logic. there were some IC's and lots single devices these monitored dozens of switches and sensors monitoring paper movement and different functions throughout the machine. It was absolutely overwhelming, but we had good instructors and good training material and we got through it. This stuff is complex , tip of the hat to you guys for figuring this all out.
Excellent work. Won't post any spoilers here, but your solutions to problems are innovative, and, more importantly, _functional._ Well done, both of you!
Pretty cool to see each hurdle being tested, troubleshooting and repaired. This machine is what brought me to your channel. Looking forward to seeing it compute again. Thanks for the videos. I’m also looking forward to your Diode testing video
@@UsagiElectric That's not just 10 years! You look like you're in your early 20s almost when clean shaven and in your 50s or later when you're about to shave lol
With a function generator, a resistor and your scope, you can create a curve tracer for the diodes. It may be that the breakdown voltage on the bad one is very low. BTW: I have found that a 1N5711 works OK as a replacement for a 1N34 in some circuits. The signals you have a large enough and slow enough that it is likely that the details of the diode don't matter much. The BAT41 is a 100V diode. I think you are only running about 25V on those diodes so that should be OK A conventional silicon diode would likely work for you if you need a higher voltage part
Just started computer sciences in university, hearing about these old vacuum computers and actually seeing them work is two completely different things! Love the video, can't wait to see this bendix execute a program... Keep up the great work!
I enjoy watching your adventures. I don't have the love for these kind of machines.... but I always enjoy a good fix-up. It encourages me to keep at it.
Looking at those cards jogged an old memory... I'm pretty sure I encountered one of these machines way in the back of a desert junkyard in the early 1990s. Man, if I could just go back in time and have another look
I've been watching a lot of this and I'd like to thank not just you but Mrs Bunny and all the little bunnies. There's a lot of sacrificing going on making these videos for us and working on this hardware. And I want you to know it's greatly appreciated. 😊
Wow wow wow, thought I'd be one of the first to say congratulations, been following this with interest from the start, now I'm watching the full video.
Regards from Spain! As a tube amp builder, is a pleasure to see people like you interested in this kind of stuff, Congrats for your channel dude. Best wishes!
Just gotta say, I love the editing in the crosstalk between Dave and Future-Dave. You are approaching Jedi level Youtubing skillz. The self-deprecating comments are fun, too. 'Uncoordinated monkey' had me snorting my coffee.
Undoubtedly, your most interesting and captivating video yet. I'll watch again to verify what I thought your troubleshooting was actually fully going. EXCELLENT. Any video where the viewer gets to burn his or her brain energy/thoughts is my kind of video. Reminds me of 3:00 AM nights when I was with DEC and trying to get a system going. No sleep and running on just coffee and a scope probe !!!
Great work. Keep at it - retro computer enthusiasts and computer historians will love to see this piece of computer history read tape and be alive again. We thank you for your efforts.
This is quite an odyssey! But I'll follow your Bendix exploration as long as it ever may take. This machine has something incomparable to it. You're doing a fascinating and invaluable job by restoring this machine, your patience and resilience are admirable! All the best of luck to you and your mates and family!
System source is amazing, Bob spent 2 hours with us this summer giving us a tour and sharing the fantastic collection and his immense knowledge, and GREAT stories!!
Thank you for again an exciting episode. It feel like a real thriller to me, with a positive ending every time. I love you man, and am looking forward to the new episode every sunday. Thanks again!
What an awesome contribution to computing history! We get in such a hurry for.the latest, greatest thing that it can be easy to fail to preserve things like this... but it was so important to human history, so getting it to work is fantastic.
Seeing the values populate on the drum and being read back correctly was just so awesome I wished there was a double-like button. What a thrilling experience. Well done!
AWESOME!! Now all you need to do is to restore a Tektronix 575 curve tracer and test the diode under load! (This only uses 1/4 the number of vacuum tubes that your Bendix uses!) Good luck!!😁
If you cannot find an exact photo diode you could put a fiber optic cable in its place and run it to another location where you can then use some other photo diode that is larger.
Not a bad idea. You should probably hide that construction behind the metal case, to keep the original appearance intact. But it would definitely solve the size problem, and you could use the more available versions of light-sensitive Germanium diodes.
Human ingenuity is simply amazing, this takes me back to when i was 9 and pulled apart my TRS-80 to see how it worked lol , my father was none to happy but it kept me from his power tools 🤣🤣 this computer is a work of art.
You probably know this already, but .... The diode test at 27:42 is only testing for opens and shorts. You need to reverse the meter leads to test for leakage. However, it's possible that it needs higher voltage for the leakage to appear. You may need to construct what would be a high voltage ohm meter to test the diode's reverse leakage at 100V (instead of the ~3V your meter uses).
As an electrical engineer...I would love to see you at some point get this to the point of performing the differential equations calcuations you mentioned in the beginning of the video! Even a relatively "simple" one would be amazing to see!
🎉 Nice! Maybe the diodes are bad in the sense that their breakdown voltage has decreased to something lower than the one they need to block. So the meter's low voltage test doesn't trigger the failure.
or gone too resistive/leaky in reverse, germanium diodes do have more reverse leakage current than silicon anyway, this wont show up on a multimeter diode test, you need a 'semiconductor analyzer' like a Peak dca55/dca75
I don’t know anything about tape computers or the bendix g15 and I have really only watched maybe 5 or so of your videos but I have to say these old printed diagrams are so charming. This has to be the first time I have sat through all of a troubleshooting montage where I didn’t understand hardly a god damn thing besides the fundamentals of basic signals and logic, and I think this speaks to the excellent editing and explanation at each point While I didn’t know what the fuck a bendix even was before a month or two ago I can say you’ve got 2 more eyes and ears patiently waiting to see this project through
Schottky diodes have reverse leakage greater than silicon but less than germanium. A high speed silicon diode should also work. The extra forward voltage drop of silicon shouldn't be a problem for a logic circuit that uses 200 volts with 20 volt logic swings.
Fun fact, an ordinary LED can act as a photo-diode that’s most sensitive to light with the same wavelength as it would emit (does NOT apply to blue/white LEDs). Since that bulb probably emits a good deal of light across a broad portion of the visible spectrum, a yellow SMD LED glued to the end of a light-pipe with the same diameter as the bad photo-diode should work; just keep in mind that LEDs of any color have a low PIV (Peak Inverse Voltage), should you try to use them as photo-diodes in a tube circuit! 😊
I was wondering about that myself, in fact it was the first thing I thought of when the germanium photo-diode was confirmed toast. Not even sure where I heard this fact but it clearly stuck in my subconcious somewhere!
Gotta love the archeological scratching of “YOU WANNA BET?” from a former technician next to the block labeled “CLOCK TRACK (PERMANENT RECORDING) TIMING TRACK” on the drawing.
![Felix "Unfair" | [Stray Kids : SKZ-PLAYER]](http://i.ytimg.com/vi/Oswujxm2Ag0/mqdefault.jpg)
Congrats! Tape data loading onto the drum! That’s quite an achievement. It’s really neat to see the data build up on the track at the pokey speed it’s read in from the tape. Such a relaxing computing pace.
Thank you!
Interestingly, what we're seeing on the scope is incrementing four words at a time, so that's actually 116-bits being transferred over at a time, which is decently fast!
@@UsagiElectric That's faster than our dial-up in 1996. lol
@@electronashyes - good catch that was funny 😂🎉
But can it run Doom?
Diaper = diagnostic program for easy repair. This one wins the "catchy acronym in the IT industry" award easily.
I thought it was a silly name until I saw the acronym, then I immediately loved it, haha.
@@UsagiElectric nearly as good as the WIPL ? and others for the centurion ?
It catches all errors and stops them in their tracks. Does it catch and prevent memory leaks, though?
Adding a program to it to dump out core drum memory to the typewriter could be funny. The dumper that uses a ton of paper.
@@UsagiElectricFitting for when the Bendix $h1t$ itself.
I got a good laugh out of the "You Wanna Bet?" that someone wrote on the schematic at 21:28. So cool to see this coming back to life!
I imagine that was added after someone wrote to that track
I put that shot from the manual in specifically because I found that hand scribbled note hilarious!
funny and also so cool to suddenly see humanity in the schematic 🎉
I've never seen someone so happy about a loaded diaper.
😂😂😂
Wait till it purges 😁
A loaded diaper means internal stuff is working!
@@UsagiElectric 🤦♂️
@@UsagiElectric I think he meant a loaded diaper, literally
As a highway engineer, even my modern computing equipment often struggles with road grading terrain models and leaves me pulling my hair out (Microsoft + Autodesk + Bentley is a recipe for chronic ulcers) so I have all the more appreciation this thing was doing it (probably more reliably) 70 years ago.
As much as highways fall apart, may I suggest you buy one of these tape machines lol
1:21 no, the correct question is, obviously, "Can it play Doom?"
Great minds think alike
Pong? The players must feed in the next move by paper.
@@afberglund2764 Might be able to play chess that way.
I came looking for this comment specifically
You have the best ability to convey complex computer jargon that I could never understand on my own. I appreciate you saving historical items like this and sharing. Many thanks. Always enjoy watching you.
Thank you so much!
The G15 is quite a complex system, even something as simple as loading in paper tape data is a fairly difficult system to understand, so I definitely wanted to take the time and explain it as clearly as I could!
@@UsagiElectric I assume it helps a lot that you are familiar with both the principles of operation for vacuum tubes and already designed and built a small, primitive computer with them.
"...anyone else restoring a Bendix G15..." I'd say that is a pretty rarefied group! 😁
You can probably count the number of us on one hand, haha.
@@UsagiElectric
@@UsagiElectric So debate in the community means you are feeling divided?
@@UsagiElectricthere was presumably a time when you could count the number on zero hands, so 👍
@@UsagiElectric Using only thumbs? Fascinating project!
The Bendix is by far my favorite of all your vintage machines. Getting closer to fully operational! I can’t wait to see it print out “HELLORLD”.!
Unfortunately it can't. I spoke with David when he was at Systems Source removing the good drum from the Bendix they have on display. I said the very same thing, "I cant wait for it to print out 'Hellorld'." David said it cant, since the Bendix is a numerical computer only. It can't do alphanumerics. Therefore no letters. The closest he could get would be printing images of the Hellorld letters. I hope he can get that far.
Me too! Been waiting for this great day! Congrats.
@@georgestephens2593Then I wonder why it even has a teletype for the interface? Would it just print out a code with numbers whenever it responds?
It might be able to punch a paper tape that you could then take over to a Model 15 Teletype to read to produce alphabetic characters.
I like the steam driven all mechanic Bendix.
I am 62 years old. Despite that fact, I have experience with a Mach 3 computer, which of course had tubes. In particular, I did a binary add with the adder circuit of one, back in the late 70s. It was interesting as the "accumulator", a set of neon bulbs, changed with every bit change of the additives., two sets of switches. It had hundreds of tubes, and was very bright and took a while to warm up, I am pretty sure just the adder circuit ran thousands of watts.
Congratulations! When I saw the data build up on the drum through the oscilloscope, I gasped!
Yes, that was awesome!
That single scope shot made the entire input system click in my head and really helped me understand what was going on!
Also, it was just super cool to see the data push around the drum line!
I know right? It was like the midcentury equivalent of a progress bar, so cool!
First let me say: Lloyd, you are a bloody legendary hero to keep coming to restore this old beast from your working days back to life and we totally appreciate you!
Grats Dave! PLEASE keep focus on this machine until it's 100% rather then cycling through projects if possible (and if Lloyd's schedule allows) because it's SO close I am all but dancing on my toe-tips here. I cannot believe how invested i've gotten into seeing the Bendix run, it's worse then with the Centurion that got me hooked on your channel in the first place, LOL.
He does need to wait on other people too, plus he needs to get some mental breaks to work on something else or this thing can burn him out a bit. I'm glad it's getting more attention lately, though! Bendix is like the new Centurion, the big project, and after that we can get on with a new big overarching project while the others get to be the fresh air between.
Lloyd is absolutely a legend!
I have a trip planned to Pittsburgh coming up in about two and a half weeks, so the Bendix will be on hold during that trip, but I am going to try to get another episode in before I go. I think the very next episode might be on the diode tester since I'm quite amped up about where we are on it!
Lloyd is a legend!
Absolutely fantastic. I was quite Skeptical that it would ever live again, "Bit more then you could chew" type of thing. But you and the community has shown, there is bite to that bark. I am in awe!
Fascinating. For some reason RUclips dropped this in my feed. It’s wholly unrelated to anything Ive ever watched (unless restoring old tractors and boats is a connection…) So naturally I didn’t understand a word you said but still found it mesmerizing that a machine like this could show signs of life and that you know how to coax it to function.
Glad to have you here, and happy to hear you enjoyed the video!
Cars/engines and analog computers/circuits are very similar, especially the head space you work in while diagnosing issues with either.
It is awesome that you (and your expert helpers) are able to diagnose such a complicated machine, and get it working. I saw the episode after this one before watching this one. MTBF gets you after decades...
Now we know why they named it DIAPER - because when it finally works, you load up your pants in astonishment! Great job!!!
Lmfao
Awesome. You are slowly becoming a master of the G15.
Oh, I'm still a long ways off, Lloyd is the master for sure!
Seeing the blocks of bits march across the scope as they were shifted onto the number track gave me goosebumps. It's incredible that you've even gotten this far on a machine that is pushing 70 years old! You're a restoration legend, and Lloyd is too for contributing his first-hand experience with this machine! I can't wait for the next video.
I remember these machines well! Stacked Winchester drives, punched tapes and cards, readers. The main sections of the entire computer like the arithmetic, analog, digital and tape drives were mounted in 19" racks about six feet tall.
Lloyd is an absolute legend. And so is this machine and your videos. Love the passion for old machines. It means they'll continue to operate for decades to come so long as people stay interested in them.
Congratualtions :) :) Really looking forward to the next epic chapter.
That's incredible. What a beautiful machine. Nice job getting this far. And I know what a mammoth task it was just to film and present this video. Thanks!
Back in the 80's I worked for a large photocopier company and ( starts with X ) was sent to a month-long training course on one of our large production machines. This was my introduction to computer logic and this machine was discrete component logic. there were some IC's and lots single devices these monitored dozens of switches and sensors monitoring paper movement and different functions throughout the machine. It was absolutely overwhelming, but we had good instructors and good training material and we got through it. This stuff is complex , tip of the hat to you guys for figuring this all out.
A belated happy 10.-22. to you!
Excellent work. Won't post any spoilers here, but your solutions to problems are innovative, and, more importantly, _functional._ Well done, both of you!
Congratulations! Excellent progress. Can't wait to see the next step.
Pretty cool to see each hurdle being tested, troubleshooting and repaired. This machine is what brought me to your channel. Looking forward to seeing it compute again. Thanks for the videos. I’m also looking forward to your Diode testing video
Came for clean shaven Dave. Stayed for the working Bendix
Every once in a while, I gotta get 10 years younger overnight by shaving it off!
@@UsagiElectric you do look so young without it!
@@UsagiElectric That's not just 10 years! You look like you're in your early 20s almost when clean shaven and in your 50s or later when you're about to shave lol
With a function generator, a resistor and your scope, you can create a curve tracer for the diodes.
It may be that the breakdown voltage on the bad one is very low.
BTW: I have found that a 1N5711 works OK as a replacement for a 1N34 in some circuits.
The signals you have a large enough and slow enough that it is likely that the details of the diode don't matter much.
The BAT41 is a 100V diode. I think you are only running about 25V on those diodes so that should be OK
A conventional silicon diode would likely work for you if you need a higher voltage part
Just started computer sciences in university, hearing about these old vacuum computers and actually seeing them work is two completely different things! Love the video, can't wait to see this bendix execute a program... Keep up the great work!
Incredible work! You guys are the pioneers of G15 restoration.
I enjoy watching your adventures. I don't have the love for these kind of machines.... but I always enjoy a good fix-up. It encourages me to keep at it.
THIS is the kind of RUclips content I really enjoy
I knew you would be able to replace the photodiode. Congrats on this great repair!
Amazing to see the data building up on the drum in real time.
So cool.
What a neat machine. Glad that new drum works after all these years. It was crazy that he was even able to get a spare.
Looking at those cards jogged an old memory... I'm pretty sure I encountered one of these machines way in the back of a desert junkyard in the early 1990s. Man, if I could just go back in time and have another look
20:25 Holy Cow! I mean, I've seen myself completely beardless, but you've dropped probably about 10 years off right there. :)
I had to do an A B comparison to make sure it was the same person. LOL
There are also 0805 SMD photodiodes cheaply avaiable, did you ever think about glueing those to some sorts of a stick and soldering tiny wires to it?
I suspect that had the Bendix engineers realized that someone would be reading their schematics 70 years later, they'd be as amazed as I am.
A journey of a thousand miles started with a single step.
An most excellent troubleshooting process, and it is so awesome.
Thanks for sharing!
I've been watching a lot of this and I'd like to thank not just you but Mrs Bunny and all the little bunnies. There's a lot of sacrificing going on making these videos for us and working on this hardware. And I want you to know it's greatly appreciated. 😊
Wow wow wow, thought I'd be one of the first to say congratulations, been following this with interest from the start, now I'm watching the full video.
Regards from Spain! As a tube amp builder, is a pleasure to see people like you interested in this kind of stuff, Congrats for your channel dude. Best wishes!
Congratulations! A big round of applause for you an LLoyd.
Oooooh, it's tryin'! That G-15 is so close to operational status I can feel it. Excellent progress!
It's super close! My guess is about a dozen flaky diodes holding us up at this point!
Just gotta say, I love the editing in the crosstalk between Dave and Future-Dave. You are approaching Jedi level Youtubing skillz. The self-deprecating comments are fun, too. 'Uncoordinated monkey' had me snorting my coffee.
Undoubtedly, your most interesting and captivating video yet. I'll watch again to verify what I thought your troubleshooting was actually fully going. EXCELLENT. Any video where the viewer gets to burn his or her brain energy/thoughts is my kind of video. Reminds me of 3:00 AM nights when I was with DEC and trying to get a system going. No sleep and running on just coffee and a scope probe !!!
Great work. Keep at it - retro computer enthusiasts and computer historians will love to see this piece of computer history read tape and be alive again. We thank you for your efforts.
Blinkenlights!!! Congratulations on hitting this major milestone! You have the patience of Job for sure...
Congratulations David. It's been a long road but I've been with you step by step.
This is so epic. Crazy passion and commitment to this machine. Big cheers!
This is quite an odyssey! But I'll follow your Bendix exploration as long as it ever may take. This machine has something incomparable to it. You're doing a fascinating and invaluable job by restoring this machine, your patience and resilience are admirable! All the best of luck to you and your mates and family!
System source is amazing, Bob spent 2 hours with us this summer giving us a tour and sharing the fantastic collection and his immense knowledge, and GREAT stories!!
Awesome work guys. I've been keenly following the Bendix adventure and it amazes me how far you've come! Can't wait for the next episode!
what's the meme...
"Can it run Crisis?!?"
awesome piece of history
Very impressive work by you and Lloyd there, David. 👍 That's a great result and a fascinating episode in this odyssey!
Awesome work you two, just watching the blinkenlights going is an amazing thing to see. You can almost smell victory.
Wow! Saving the past for the future, bravo.
WOW! I took a screenshot of the blinkenlights for my wallpaper Man. What an awesome achievement!! Heartiest congrats, Sir.
For some reason 21:28 "clock track (permanent recording)
Never though I'd listen to the end. You made this quite interesting for someone who's note into vintage "antique" computers. Good job on the repair.
Congratulations, that is amazing debugging and circuit tracing work!
Lovely to see this old beast coming back to life, and kudos to the original designers who got so much out of the resources they had.
Thank you for again an exciting episode.
It feel like a real thriller to me, with a positive ending every time.
I love you man, and am looking forward to the new episode every sunday. Thanks again!
be me. dont know wtf is going on but have been invested for ages. finally. it boots. a single tear for this machine I dont know anything about.
Congratulation to both you and Loyd, seeing the neons flicker must have been amazing!
What an awesome contribution to computing history! We get in such a hurry for.the latest, greatest thing that it can be easy to fail to preserve things like this... but it was so important to human history, so getting it to work is fantastic.
Seeing the values populate on the drum and being read back correctly was just so awesome I wished there was a double-like button. What a thrilling experience. Well done!
AWESOME!! Now all you need to do is to restore a Tektronix 575 curve tracer and test the diode under load! (This only uses 1/4 the number of vacuum tubes that your Bendix uses!) Good luck!!😁
This is one of my favorite channels for stuff I didn't even know I wanted to know. Thanks.
Very nice troubleshooting. Don't stop now, this is quite an achievement! Can't wait to see more.
this is the most excited I think anyone has ever been over a 67 year old loading a diaper.
Now now, someone with the internet experience your avatar and subscriptions suggest should know better than to think that...
@@DaryxFox You are right, and I hate it.
@@DaryxFox
Please stop I am in enough pain as it is
LoL😅
LoL😅
but can it run DOOM?
No
Maby, depends on the display you have.
@@Levi-op2hc printout only
Super cool, man! Excited to to see the next stage of getting this neat machine running again!
Absolutely fascinating! Congratulations on getting the Bendix to boot.
If you cannot find an exact photo diode you could put a fiber optic cable in its place and run it to another location where you can then use some other photo diode that is larger.
Not a bad idea. You should probably hide that construction behind the metal case, to keep the original appearance intact. But it would definitely solve the size problem, and you could use the more available versions of light-sensitive Germanium diodes.
Super cool accomplishment David!
I can't wait to see that printer output HELLORLD.
Awesome progress. Being able to witness the journey is amazing.
Human ingenuity is simply amazing, this takes me back to when i was 9 and pulled apart my TRS-80 to see how it worked lol , my father was none to happy but it kept me from his power tools 🤣🤣 this computer is a work of art.
You probably know this already, but .... The diode test at 27:42 is only testing for opens and shorts. You need to reverse the meter leads to test for leakage. However, it's possible that it needs higher voltage for the leakage to appear. You may need to construct what would be a high voltage ohm meter to test the diode's reverse leakage at 100V (instead of the ~3V your meter uses).
Big congrats, and I love the teaser shot at the end...
Incredible work! You are an inspiration!
Bravo! Good progress, all involved with the Bendix G15! 😎🥳
Excellent news - I'm really loving this journey!
As an electrical engineer...I would love to see you at some point get this to the point of performing the differential equations calcuations you mentioned in the beginning of the video! Even a relatively "simple" one would be amazing to see!
That clip of the Fortran cards gave me flashbacks! Awesome video, man!
Wow! Great work! HAL is slowly beginning to feel better! 😄 Yes, he can feel it. He is beginning to feel better.
Keep up the great work. It's amazing to see a piece of living history being brought back.
🎉 Nice! Maybe the diodes are bad in the sense that their breakdown voltage has decreased to something lower than the one they need to block. So the meter's low voltage test doesn't trigger the failure.
or gone too resistive/leaky in reverse, germanium diodes do have more reverse leakage current than silicon anyway, this wont show up on a multimeter diode test, you need a 'semiconductor analyzer' like a Peak dca55/dca75
Seeing the data shift in on the scope is such a cool moment!
What a project, I'm jealous :D
Pretty cool becoming one of the very few Bendix techs. Excellent progress!
This is pretty fantastic! Hats off to everyone involved
I don’t know anything about tape computers or the bendix g15 and I have really only watched maybe 5 or so of your videos but I have to say these old printed diagrams are so charming. This has to be the first time I have sat through all of a troubleshooting montage where I didn’t understand hardly a god damn thing besides the fundamentals of basic signals and logic, and I think this speaks to the excellent editing and explanation at each point
While I didn’t know what the fuck a bendix even was before a month or two ago I can say you’ve got 2 more eyes and ears patiently waiting to see this project through
I’ve been waiting so long for this. I feel like Tool just released another album.
Schottky diodes have reverse leakage greater than silicon but less than germanium. A high speed silicon diode should also work. The extra forward voltage drop of silicon shouldn't be a problem for a logic circuit that uses 200 volts with 20 volt logic swings.
Fun fact, an ordinary LED can act as a photo-diode that’s most sensitive to light with the same wavelength as it would emit (does NOT apply to blue/white LEDs). Since that bulb probably emits a good deal of light across a broad portion of the visible spectrum, a yellow SMD LED glued to the end of a light-pipe with the same diameter as the bad photo-diode should work; just keep in mind that LEDs of any color have a low PIV (Peak Inverse Voltage), should you try to use them as photo-diodes in a tube circuit! 😊
I was wondering about that myself, in fact it was the first thing I thought of when the germanium photo-diode was confirmed toast. Not even sure where I heard this fact but it clearly stuck in my subconcious somewhere!
@@exidy-ytanother fact: these photovoltaic panels can also work in reverse, just not for long and not well, they emmit a light close to or at ir.
Good idea. Alternatively an ordinary through-hole yellow LED of the correct size may do the job sans light pipe.
@@SimonBauer7 So do transistor junctions....
so you add more resistors to drop volts in and an amp tp up volts out ?
Man, what a trip! Congratulations (I will never stop repeating that you are nuts, in a good way)
2 plus 2 equals 4. Thanks for the tech history! Pretty amazing that it works and they moved it to you!
its nice when a father and his son makes a video together
20:25 you're so excited... lol 😂 good work so far guys!
Gotta love the archeological scratching of “YOU WANNA BET?” from a former technician next to the block labeled “CLOCK TRACK (PERMANENT RECORDING) TIMING TRACK” on the drawing.