I use a small (diameter) piece to go over the long leg. Don't really even need to shrink it, as it will probably shrink at least partially just from soldering. And if not, it's not going anywhere ... :-)
Listening to you reassemble the display with the hinges around the 18 minute mark reminded me of the time when I was learning laptop repair in 90s at my first real IT job. I was tasked with repairing a machine that was a somewhat newer model at the time, a Toshiba Tecra 720CDT. It needed it's mainboard replaced due to a bad RAM expansion slot. This model was a complete tank of a machine in addition to being fairly expensive for the time. The tech who was helping me said the first step in replacing the mainboard (which was at the bottom of the machine) was to take apart the upper part of the machine and remove the LCD panel and backlight inverter. I asked why this was as most other contemporary laptops by Toshiba, IBM, HP or Compaq usually required you remove the top half of the laptop and had the display cables plug in usually just under that assembly. You rarely had to remove the relatively fragile LCD bezel and panel unless the LCD itself was bad. The tech explained that on the 720CDT Toshiba had run the display signal & power in 1 cable from the LCD panel & backlight inverter down through the rest of the machine. Not only did they plug in the cable directly to the main board but also attached a grounding strap & screw to the mainboard. Only problem was when you took the top half of the machine off (LCD, hinges, and the assembly the keyboard and mouse buttons were part of) you also had to remove 3 other smaller boards (audio, modem & power) that plugged into the main board and an inner frame piece that supported those 3 boards before you could get to the other end of the cable. There wasn't nearly enough slack in the cable unless you disconnected it from the LCD panel & backlight inverter first! On that model in order to replace that one part, which admittedly was a big part, you had to disassemble the laptop 100% of the way in order to do the job correctly. Other techs had tried to do the job without disconnecting that cable from the LCD panel & backlight inverter but usually ended up damaging the cable in the process as there was basically no slack in it at all.
I have been in the hospital for a month now with a painful condition and on my better days it is great to see you upload. You are very good at keeping a good a secdual.
PS/2 architecture was designed with hindering the copying by other companies in mind. They used to be complicated and time/money consuming to be cloned on purpose by IBM
I'm not sure that's really true. IBM were happy for clone makers to licence the new architecture, they just wanted to reacquire control of the platform. I suspect the awkward aspects of the PS/2 were perceived as perfectly reasonable inside IBM.
What a remarkable undertaking that was. It's an immensely appealing device once assembled and the fact that it was a rental makes it even more astonishing that it's still with us. I learned to repair IBM time clocks in the early 70s and they were orders of magnitude more complex, capable and vastly larger than other such devices. Their traditional business model was to be in a whole different league from other companies and it did work at certain times in certain sectors.
Yeah, I never made any videos about it, but I have a small collection of Selectrics, they are fantastic machines too! IBM definitely made amazing stuff even before the PC
Green with envy here. I have a bit of everything, but no briefcase systems. I've not once ordered an axial cap, always bent radials, same as you have here, no issues in nearly forty years.
The plastic fasteners are called push rivets. Very common in cars. They are actually a great idea: lighter than screws and won’t come undone from vibration.
Used to used one of these for a volunteer thing up into the late 1990s. Nobody had a more modern notebook. The PS/2 was available and worked fine for what we were doing. I do not miss having to lug it around. But it was neat to look at.
Fantastic restoration, well done. I’ve been waiting excitedly for you to complete the reassembly, not only just to see the finished product, but also because I have a Japanese IBM PS/55 Type 5545 sitting in pieces that I need to reassemble myself. It seems to be almost identical to the PS/2 P70, so your videos will be very important references for my own efforts :P Thank you for the great entertainment so far, your channel is severely underrated!
I like these old portables. It is cool to see how "advanced" they are. I never knew the IBM was with this packed. It's also so cool with 3d printers becoming more common so many of these old computers get a second chance to live because stupid latches or hinges are not as big of a problem anymore. Speaking of that I do gotta fix my powerbook hinges at some point.
Awsome restoration, I totally LOVE gas-plasma displays, a P70 will hopefully be part of my collection some day too, along side my Compaq Portable III and Toshiba T3100 plasmas.
Nice job you did with this IBM. We like to see you work on IBMs. Steven is working now on a 5150 for a customer. Greetings from Steven from the Netherlands
That's got to be coolest vintage PC, despite being a nightmare to restore! The hinged screen reminds me of an X Window System terminal I used many years ago. I think it was a DEC (Digital Equipment Corporation) machine but may have been a Sun Microsystems one.
Those keyboard locks almost match the more purple hue of the accent plastics in the late 90's early 2000's Aptiva and Netvista line of computers. It's a nice modern homage! I think it looks great!
The first true ibm compatible coumputer i purchased was a IBM PS/2 Model 70 new in the box in 1991 for $300.00 dollars from an ad in computer shopper. It was loaded with IBM dos 5 and OSHA certification and training software. It was also 20mhz, I eventually upgraded it to 6mb, XGA2, and Cyrix DLC 50mhz but it ran at 40mhz. Used it up till late 90s for work but my ex wife got rid of it after divorce.
Excellent work as always and a very strangely built machine for not many people at the time and even now. I know those orange panasonic flat panels are very shout after at the retro community and only few of them work now but yours looks to be really in great condition! I have a feeling that the floppy drive cover did not go and klik all the way in at the bottom right corner ... Cheers from Greece keep up!
Thank you. You are absolutely right. the bottom right corner is not perfectly flush. I tried to fix it after the vid but with the same result. I need to check what's pushing the cover out a few mm.
Electrolytic caps of the era are a lot larger than modern ones. They're also higher ESR than modern ones, which if you uprate the voltage on modern ones, you'll more closely match both size and behaviour.
Yes, almost all caps I install are smaller than the original caps in my projects. But the size difference was unusually big on this board. This makes me a little worried that some of them might be some special type eg. high-frequency caps
Love how it came out, cool project to watch all the way through. Please update if you figure out how to overclock it, would love to do so for mine as well. --Paul
Herculean effort all round. I have the P70 and a 55SX both with that dreadful floppy drive, which is not working on either machine and which seems to be unique to these two models. I have tried to bodge a standard 34 pin floppy drive to work on the 55SX but it refuses to cooperate so at least I have seen what fixing the original drive entails, which seems to be my best option. I am hoping that any capacitor hasn't leaked too badly and destroyed the PCB.
Interestingly, if it was manufactured at IBM's facility in Spango Valley in Greenock, that site no longer exists as an IBM facility. They abandoned Spango Valley and downsized to a call centre.
The leads of a capacitor are like tiny inductors (all wires are) and are responsible for the ESL (equivalent series inductance) of the cap. This is why SMD caps have very little ESL -- no leads at all! ESL prevents the cap from reacting to high freq transients, which is bad. But in this application the cap is probably just for low freq bulk capacitance and I doubt you will see ill effects. But definitely don't do this with low ESR or decoupling caps. Great video as always!
Man, I do it that way: Add new solder and heat it up and pull it out at the same time. It is easier for me. 15:15 - mounting pegs on board of Commodore SX-64
Man I tried tracking one of these down a few years ago but went with the 5140 instead which incidentally arrived broken. I have the compaq portable 3 though which I think is similar. They are fun machines!
Most likely, it is necessary to modify the bios so that the computer starts with non-standard frequencies for this ps/2 model. I read somewhere that some specialist modified the bios on another ps/2 model, which also did not want to start with overclocking and the computer was successfully launched with moded bios. But I can't remember where I read it. Most likely on Ardent tool. I also need to overclock my ps/2 model 55sx, but I don't know where to get a modified bios or who to contact with such a request. By the way, I read somewhere on ardent tool that a lot of ps/2 models do not start with overclocking at all, most likely, bios modification was discussed in the same topic.
Hey! Great vid. I have a somewhat similar machine that I just got. It was used for Hearing Testing, probably at schools. It has a PC Chips VGA that has what looks to be a special ribbon cable to power the LCD screen. Everything works. I saw that it had an AGP 2x port, so I wanted to do some retro game testing to check it out. Well, the AGP output is always blue, it's not outputting correctly. I've tried multiple working cards from other systems. Have you ever experienced anything like that?
I'm surprised you didn't put a math coprocessor in there while you had it open or was that socket for one of those until overdrive chips if you wanted to replace the CPU that was on the board?
Some AMD CPUs had an internal multiplier that would set to a different speed if your set the board to x2. But that's the k6 era i remember. Don't know about these older ones.
@@Epictronics1 If you still want to increase the clock frequency, I'd get an interposer or try and jump the clock pins on the CPU socket like you've done before - a lot of these ICs were cherry picked to suit the shared clock speed on the mainboard and I doubt they're as flexible as standard PC clone boards of the time.
Hi, 250V is not a safety voltage (cap rated voltage), it has to be done with some precautions. I don't know you country's law. Maybe you need to have a 2.5mm safety gap between conductive parts, add some insulation layers, you shouldn't be able to touch any part at 250V with a "finger as thin as a baby one" once assembled, pass the agreements if the modification is not an equal replacement...
Shoutout to the little speck of something @12:03 that landed onto the top platter and getting sealed inside :D
lol, I only noticed in edit 😅I'll get it out tomorrow
Amazing restoration job!
Thanks!
The radial to axial cap modification is perfectly fine. I would only add a layer of heatshrink tubing over the whole thing.
I use a small (diameter) piece to go over the long leg. Don't really even need to shrink it, as it will probably shrink at least partially just from soldering. And if not, it's not going anywhere ... :-)
Listening to you reassemble the display with the hinges around the 18 minute mark reminded me of the time when I was learning laptop repair in 90s at my first real IT job.
I was tasked with repairing a machine that was a somewhat newer model at the time, a Toshiba Tecra 720CDT. It needed it's mainboard replaced due to a bad RAM expansion slot. This model was a complete tank of a machine in addition to being fairly expensive for the time.
The tech who was helping me said the first step in replacing the mainboard (which was at the bottom of the machine) was to take apart the upper part of the machine and remove the LCD panel and backlight inverter.
I asked why this was as most other contemporary laptops by Toshiba, IBM, HP or Compaq usually required you remove the top half of the laptop and had the display cables plug in usually just under that assembly. You rarely had to remove the relatively fragile LCD bezel and panel unless the LCD itself was bad.
The tech explained that on the 720CDT Toshiba had run the display signal & power in 1 cable from the LCD panel & backlight inverter down through the rest of the machine. Not only did they plug in the cable directly to the main board but also attached a grounding strap & screw to the mainboard. Only problem was when you took the top half of the machine off (LCD, hinges, and the assembly the keyboard and mouse buttons were part of) you also had to remove 3 other smaller boards (audio, modem & power) that plugged into the main board and an inner frame piece that supported those 3 boards before you could get to the other end of the cable.
There wasn't nearly enough slack in the cable unless you disconnected it from the LCD panel & backlight inverter first!
On that model in order to replace that one part, which admittedly was a big part, you had to disassemble the laptop 100% of the way in order to do the job correctly. Other techs had tried to do the job without disconnecting that cable from the LCD panel & backlight inverter but usually ended up damaging the cable in the process as there was basically no slack in it at all.
I have restored the smaller Toshiba 300CT. It's an old video, but you may want to watch it if you want some Toshiba nostalgia :)
I have been in the hospital for a month now with a painful condition and on my better days it is great to see you upload. You are very good at keeping a good a secdual.
Thanks! Get well soon!
PS/2 architecture was designed with hindering the copying by other companies in mind. They used to be complicated and time/money consuming to be cloned on purpose by IBM
Meanwhile the PS/2 connectors got cloned eventually, considering they used similar signaling to the AT keyboard
@@sonicunleashedfan124 At least they tried🤔
@ true
I'm not sure that's really true. IBM were happy for clone makers to licence the new architecture, they just wanted to reacquire control of the platform. I suspect the awkward aspects of the PS/2 were perceived as perfectly reasonable inside IBM.
I love your “Oh no, we have an errr-ohr!” moments.
Me too.. haha
What a remarkable undertaking that was. It's an immensely appealing device once assembled and the fact that it was a rental makes it even more astonishing that it's still with us. I learned to repair IBM time clocks in the early 70s and they were orders of magnitude more complex, capable and vastly larger than other such devices. Their traditional business model was to be in a whole different league from other companies and it did work at certain times in certain sectors.
Yeah, I never made any videos about it, but I have a small collection of Selectrics, they are fantastic machines too! IBM definitely made amazing stuff even before the PC
@@Epictronics1 That's a perfect example. They rewrote the book on what a typewriter can be and do.
What a fantastic restore of a system that was in rough shape
Thanks :)
Green with envy here. I have a bit of everything, but no briefcase systems. I've not once ordered an axial cap, always bent radials, same as you have here, no issues in nearly forty years.
Great! Those axial caps are starting to get rather expensive!
Fantastic job. You are the IBM hero👍
Thanks :)
I remember working on these in the 1990's. Always more difficult to re-assemble than fix.
The plastic fasteners are called push rivets. Very common in cars. They are actually a great idea: lighter than screws and won’t come undone from vibration.
Thanks!
Used to used one of these for a volunteer thing up into the late 1990s. Nobody had a more modern notebook. The PS/2 was available and worked fine for what we were doing. I do not miss having to lug it around. But it was neat to look at.
A job very well done, it looks amazing.
Thanks!
Fantastic restoration, well done. I’ve been waiting excitedly for you to complete the reassembly, not only just to see the finished product, but also because I have a Japanese IBM PS/55 Type 5545 sitting in pieces that I need to reassemble myself. It seems to be almost identical to the PS/2 P70, so your videos will be very important references for my own efforts :P
Thank you for the great entertainment so far, your channel is severely underrated!
Thanks! Yes, I think the 5545 is identical, except for the funky keyboard layout.
I like these old portables. It is cool to see how "advanced" they are. I never knew the IBM was with this packed. It's also so cool with 3d printers becoming more common so many of these old computers get a second chance to live because stupid latches or hinges are not as big of a problem anymore. Speaking of that I do gotta fix my powerbook hinges at some point.
Yeah, 3D printing is a blessing for these machines!
Aways like your videos, very informative and entertaining.
Thank you
Insane repair bloke!
Thanks
Awsome restoration, I totally LOVE gas-plasma displays, a P70 will hopefully be part of my collection some day too, along side my Compaq Portable III and Toshiba T3100 plasmas.
I've got a T3100 too! But still looking for a Compaq Portable :)
used one of these back in the 90's.
Nice job you did with this IBM. We like to see you work on IBMs. Steven is working now on a 5150 for a customer. Greetings from Steven from the Netherlands
Thank you :)
That's got to be coolest vintage PC, despite being a nightmare to restore! The hinged screen reminds me of an X Window System terminal I used many years ago. I think it was a DEC (Digital Equipment Corporation) machine but may have been a Sun Microsystems one.
I absolutely agree. This machine pretty much immediately became one of my favorites :)
An epic journey and remarkable conclusion. Congrats! This is quite the bespoke luggable PC.
Thanks!
Those keyboard locks almost match the more purple hue of the accent plastics in the late 90's early 2000's Aptiva and Netvista line of computers. It's a nice modern homage! I think it looks great!
What a wild puzzle; great work! I hope someone comes through that can decompile the BIOS and see if there’s an overclocking lock.
Thanks! Yeah, we need a BIOS hacker in this community :)
The first true ibm compatible coumputer i purchased was a IBM PS/2 Model 70 new in the box in 1991 for $300.00 dollars from an ad in computer shopper. It was loaded with IBM dos 5 and OSHA certification and training software. It was also 20mhz, I eventually upgraded it to 6mb, XGA2, and Cyrix DLC 50mhz but it ran at 40mhz. Used it up till late 90s for work but my ex wife got rid of it after divorce.
What a beautiful machine, great restoration.
Thank you :)
What an awesome series man🎉
Thanks!
Awesome job, such an interesting system for sure.
Thanks!
Yay at last the P70 is done! What an adventure. Too bad about the overclocking. I hope you figure that out someday.
I hope so too! This machine has taken up half the bench for weeks! Nice to have it reassembled again
Excellent work as always and a very strangely built machine for not many people at the time and even now. I know those orange panasonic flat panels are very shout after at the retro community and only few of them work now but yours looks to be really in great condition!
I have a feeling that the floppy drive cover did not go and klik all the way in at the bottom right corner ...
Cheers from Greece keep up!
Thank you. You are absolutely right. the bottom right corner is not perfectly flush. I tried to fix it after the vid but with the same result. I need to check what's pushing the cover out a few mm.
Electrolytic caps of the era are a lot larger than modern ones. They're also higher ESR than modern ones, which if you uprate the voltage on modern ones, you'll more closely match both size and behaviour.
Yes, almost all caps I install are smaller than the original caps in my projects. But the size difference was unusually big on this board. This makes me a little worried that some of them might be some special type eg. high-frequency caps
Great video
Thank you :)
@Epictronics1 thanks
Those push-pin fasteners are quite common in automotive applications, so there's an avenue of search should you need to replace some at some point.
Love how it came out, cool project to watch all the way through. Please update if you figure out how to overclock it, would love to do so for mine as well.
--Paul
Thanks! I'll keep trying :)
so freaking NEAT
Herculean effort all round. I have the P70 and a 55SX both with that dreadful floppy drive, which is not working on either machine and which seems to be unique to these two models. I have tried to bodge a standard 34 pin floppy drive to work on the 55SX but it refuses to cooperate so at least I have seen what fixing the original drive entails, which seems to be my best option. I am hoping that any capacitor hasn't leaked too badly and destroyed the PCB.
Good luck!
The first computer I ever used
Interestingly, if it was manufactured at IBM's facility in Spango Valley in Greenock, that site no longer exists as an IBM facility. They abandoned Spango Valley and downsized to a call centre.
The P70 was manufactured in the US and Japan. Not sure if they were manufactured in Greenock too, but quite likely
The leads of a capacitor are like tiny inductors (all wires are) and are responsible for the ESL (equivalent series inductance) of the cap. This is why SMD caps have very little ESL -- no leads at all! ESL prevents the cap from reacting to high freq transients, which is bad. But in this application the cap is probably just for low freq bulk capacitance and I doubt you will see ill effects. But definitely don't do this with low ESR or decoupling caps. Great video as always!
Thanks! I'll run it for a while and see how it behaves. If it misbehaves, I'll swap the caps
Awesome video as always!!
nothing wrong with makeshift axial caps, but it's usually a good ideal to put heat shrink on it.
I probably should have :)
Yeah the only issue would be at higher frequencies it may have enough inductance to turn into an antenna. Looks good
@@GaRbAllZ I'll find out!
I should have read the comments before I posted.
Man, I do it that way: Add new solder and heat it up and pull it out at the same time. It is easier for me.
15:15 - mounting pegs on board of Commodore SX-64
That would totally work.
Man I tried tracking one of these down a few years ago but went with the 5140 instead which incidentally arrived broken. I have the compaq portable 3 though which I think is similar. They are fun machines!
The Compaq Portable is a gem too. I'd love to have one
@ well I do have 2 of them ;)
@@SnipE_mS :)
sure there's only a 50v cap across the air-gapped part of the board?
I better check...
Yepp. 50v caps. a bit strange actually
@@Epictronics1 who needs REFAs 🫢
If it were me,. I'd dump the BIOS and have a peak at the code using BinWalk. It may be possible to rewrite some of the code to allow overclocking.
Unfortunately, I'm not skilled in BIOS hacking
you could push out the tabs and then sand them. You wouldn't have to take the keyboard apart again.
Too late, lol. Apparently, they need to be 1.55mm
they are called push lock pins
Thanks!
Commodore sx-64 uses those plastic rivet push pin things on the boards inside. Next luggable repair?
Absolutely. I don't know when, but we are definitely taking on the SX-64
@Epictronics1 I have 3 of them so if you need parts let me know!
@@justinthomas2458 Thanks, I appreciate that. My machine is working but I have not done a thorough test yet. I just played a game for half an hour
Hello. Thank you for the video.
What PTFE grease do you use?
Thanks. I think the can I have is CRC branded, but it shouldn't matter. Just get the brand they have where you normally shop for lubricants
Most likely, it is necessary to modify the bios so that the computer starts with non-standard frequencies for this ps/2 model. I read somewhere that some specialist modified the bios on another ps/2 model, which also did not want to start with overclocking and the computer was successfully launched with moded bios. But I can't remember where I read it. Most likely on Ardent tool. I also need to overclock my ps/2 model 55sx, but I don't know where to get a modified bios or who to contact with such a request. By the way, I read somewhere on ardent tool that a lot of ps/2 models do not start with overclocking at all, most likely, bios modification was discussed in the same topic.
Same problem with the 5170, but someone hacked it :)
We need a specialist with good knowledge of assembler, he can deal with bios 😊
@@krizator That would be great. I have several boards that need minor BIOS hacking
Please upload the list of caps to Caps Wiki
I should probably test the machine for a bit first. I'm not convinced that all the original caps were general-purpose caps yet.
Hey! Great vid. I have a somewhat similar machine that I just got. It was used for Hearing Testing, probably at schools. It has a PC Chips VGA that has what looks to be a special ribbon cable to power the LCD screen. Everything works. I saw that it had an AGP 2x port, so I wanted to do some retro game testing to check it out. Well, the AGP output is always blue, it's not outputting correctly. I've tried multiple working cards from other systems. Have you ever experienced anything like that?
Thanks. It sounds like an interesting machine. Is it a custom one-off, or does it have a model name/number?
I have to wonder, when you are just replacing components, why not just cut the part out, it's less heat/stress to remove a leg.
no left over screws? :-P
No! maybe next time :)
The Surface Pro from yesteryear 😅
I'm surprised you didn't put a math coprocessor in there while you had it open or was that socket for one of those until overdrive chips if you wanted to replace the CPU that was on the board?
Yes, I think I have a math co for this board, but I don't think I have any games that would take advantage of it
Some AMD CPUs had an internal multiplier that would set to a different speed if your set the board to x2.
But that's the k6 era i remember. Don't know about these older ones.
Something similar exists for these boards too but I don't have one of those, unfortunately.
Is the clock crystal causing the bus for graphics etc. being overclocked too fast for it causing a non boot?
The graphics card is definitely a suspect, but it could be any, or many! chips
@@Epictronics1 If you still want to increase the clock frequency, I'd get an interposer or try and jump the clock pins on the CPU socket like you've done before - a lot of these ICs were cherry picked to suit the shared clock speed on the mainboard and I doubt they're as flexible as standard PC clone boards of the time.
Did you replace the clock battery?
Yes, with the matching battery. I'll replace it again with two modern CR2032s later
That monitor flickers almost like a CRT. What's the refresh rate?
I actually don't know. but it's something between standard camera settings
Most likely 70 or 75Hz
It won't over clock because of the memory speed
I hope you're wrong, but it's quite possible. These boards are made to only work with one specific type of RAM stick :(
Hi, 250V is not a safety voltage (cap rated voltage), it has to be done with some precautions.
I don't know you country's law. Maybe you need to have a 2.5mm safety gap between conductive parts, add some insulation layers, you shouldn't be able to touch any part at 250V with a "finger as thin as a baby one" once assembled, pass the agreements if the modification is not an equal replacement...