Every SIMM slot in my P70 is broken. Someone before me actually hot glued wedges of wood between the SIMMs to hold them in place. I haven't even attempted to fix it because it works and I don't want to tempt fate!
That explains a lot lmao. I hadn’t used any of my soldering stuff from late 2019 to early 2023 (I wonder what was going on in the world then that kept me away 🤔) and by ’23 the solder wick was super uncooperative!
3D printing services from PCBway are nice but there's something super neat about printing a part, realizing it needs to be slightly different, and then just changing the model slightly in the slicer and just printing it again :3
Saved by the data sheet. Thankfully it was a common enough part to have an easily found datasheet. There are so many chips where it is almost impossible to find a data sheet now. Also a lesson learned check your voltages before desolding the chip. Though without desoldering the chip you wouldn't have known which trace was vcc and needed fixing. In the future for drives that don't spin. If you power the drive and assert the drive select and motor on signals on the cable the drive should spin so you don't need to actually connect to a working system to test the motor. For a proprietary cable like this drive unless you find the pin out it might be difficult to do though.
I really enjoyed seeing you fix that floppy drive. We've been in these phases of just trashing so many things that I just accumulate spare storage and optical drives and pretty much recycle the rest...it's nice to see these relics get some real attention! If we had kept all the old machines we would be swimming in them.
Hi Epictronics, what a nice machine the PS/2 P70. It was a great system for his time. I have lot fun with repair this machines. Greetings from Steven from the Netherlands
Opening this keyboard reminds me of the insanely difficult process to open another IBM keyboard: the Model M2. I had to use countless guitar picks to keep a bunch of plastic clips (on the edges and also all over the middle of the keyboard) pried open while trying to pull the top case/plate out... Traumatizing stuff! XD
I would have used the grinding pen to remove the corrosion on the chip legs so that the solder could "bite" on to fresh metal. Also any PCB tracks that have the black spots on them need to have the solder mask removed and cleaned with a mild acid to remove the corrosion that has seeped under the solder mask. If you do not do this the trace will fail again some time later. I noticed this under the motor driver chip and around the C5 silk screen print on the PCB. Make sure to tin or use solder mask paint on all exposed copper traces to prevent further oxidation from the air after cleaning up the corrosion. You may want to run a thin wire to repair the damaged track as the solder blob is not very mechanically strong and may fail later (also it does look a bit ugly). You should add some flux to the solder brad before using it as that will make it wick better. If you were worried about damaging the motor with the hot air you could have covered it with a metal shield to deflect the heat such as aluminum foil. Although I would not be super concerned about it as when the magnets in the disk cooled down they should regain their magnetism. I have a old Weller soldering iron that uses a magnet in the soldering tip to control the temperature of the iron and it works quite well. When the iron get to temp the magnet demagnetizes and signals to the base station to kill the power to the element. When it cools down enough it re-magnetizes and turns the element back on again.
Motordriver, just a tipp: Reflow with leaded solder, use solder braid to remove as much as you can, reflow with solder, use solder braid, resolder, done. Leaded solder is far enough to use and even to prepare for rework by hot air.
I am still shocked, even knowing that was a 'rental' system, as to how clean that keyboard (really the whole system) is. What a job though, taking that keyboard apart. Great work on the drive, who would have known?!?!
Finding that broken trace was unbelievable! It's always the last thing you check. Lol great work after the 2nd boot I think I would have pulled all but 1 stick of ram lol
If you want to un-Loctite a screw, an impact screwdriver is a very useful tool, since Loctite isn't designed to take shock load. A sudden torque on the screw will break it loose.
Depending on where you are in the world, this solution may or may not work for removing the stuck screw that holds the motor on. A very good solvent for glue, primarily for cyanoacrylate (super glue) but also works on some extent for epoxy: nitromethane. Yes, the stuff they use in racing fuels. I keep a little dropper bottle of it in my work kit, together with the deoxit and the silicone oil. In the US it is legal to buy (though not easy to find). In other parts of the world it may not be - definitely in Europe it isn't. Too bad because it's a very useful tool to have.
Always happy whenever you drop a new video! I really enjoy how low-key educational they are simply by how you explain and show things in a way that I find easy to follow.
Oh no, the struggle with floppy drive... I just swapped the original drive to Sony MFP920 and modded floppy cable. Eject button is of course different but it did work nicely.
That drive!!!! I have a similar issue, but the motor needs a small nudge to get going but the drive is still not able to boot. I temporarily gave up and put a Mitsubishi drive instead, cut the translucent plastic insulation sheet at the back and massaged the connector to fit on the opposite side. The Mitsubishi is known to be more reliable anyway. If only I could get that locktite off!!!
@@Epictronics1 No. I had a drive with exactly the same fault, nudge it and it works. The problem is the chip UNDER the flywheel is partially bad and some of the motor windings are not being driven. The fix is to replace the chip.
Next time you need to desolder a chip like that, you might want to try wrapping a thick piece of copper wire around it, then soldering it to all the pins, then heating it up with the iron until all the solder is molten and lifting or flicking it off. Haven't tried it myself, but I've seen this technique used before, and it seems to work pretty well, although it does use a lot of solder.
Ah, I used to have a P70 as well. Got rid of it because it had broken SIMM slots. Wish I had kept it since by now I could find the resources to replace them.
I'm pretty sure you can safely disassemble the motor assembly on such a floppy drive. To defeat stubborn loctite use heat. Use the tip of your soldering iron to heat the screw up as hot as you possibly can. Then it should come out easily.
You should be able to get that motor out. It's likely those 4-5 screws on the trace side (the motor 'board' is actually traces printed on a steel substrate, I believe) and then around the spindle on the other side? Those blue SMT chips with no markings, I would tend to think they're zero-ohm jumpers given the 'J' next to them on the plate.
You remove Loctite with heat... What you can do is get a crap soldering pencil. 100 watts if possible. Find a Phillips screwdriver that has a shaft the same diameter as the crap soldering pencil. Cut off the screwdriver shaft as short as you're willing to do, use it in the crap soldering pencil as a soldering tip, and let it heat up. Use the entire crap soldering pencil with the screwdriver tip installed as a hot screwdriver. You may try using the hot air rework to help get the screwdriver tip nice and hot in addition to the crap pencil iron.
Nice fix! Looks like I need to do my floppy drives as well. Even though I am going with a Gotek and the adapter board, I'll clean and recap them. I have some vanilla P70s as well as a GE WorkMaster.
@@Epictronics1 Thanks! Looks like they are getting scarce! We used to use them for programming PLCs (initially the GE Series Six PLC, and later on, the GE 90-30 and 90-70 PLCs). At one point we were literally throwing the WorkMaster I units (IBM 5155 PCs) away. I "rescued" the outer cover of one and repurposed it as my "$10,000 trash can". The venerable old Series Six is almost gone, so these aren't all that useful these days. Certainly not for programming PLCs. :) I doubt that I will install Windows on mine since it didn't come with Windows from GE. A fresh copy of DOS and then LM6 and I'll be all set. :) As for the caps, I had thought of that, and then realized that I would probably never remember what the values of the caps that I removed were (I'm sure that it's written down somewhere). :)
@@MrWaalkman Yes, for sure. It will be easy to find the correct value in the future. I guess, you could write it on a sticker to save time. They all have a designator, like C1, C2, and so on
Removing loctite, heat is the best but you need to heat it to something like 200C. Methylene Chloride or acetone might work depending on what type of thread lock it is.
The devil always lays in the details... When I saw that 4 Volt in the little scope's screen I said no way that voltage is correct! It should be 12... That may indicate also that the previous driver Hitachi chip may be also working and you are really lucky that the crack was not below the chip. Great project on a very interesting machine maybe there is a BIOS that has a faster RAM counter out there? Anyways excellent video as always, keep up! Cheers from Greece
Do you know that the screw is maybe other way around? If you try to open it and it is threaded the other way, you try to screw it on even more. They often do those "wrong screws"/Clockwise/counterclockwise because it would spin free with the movement of the motor.
Removing the motor board is definitely a bad idea, I’ve removed a hub motor assembly and after reassembling wouldn’t read disks unless I loosened the screws and move the motor board around until disks read correctly.
The board has a zero track sensor that has to be re-set correctly. But it's easy to fix using some calibration software. At least on Amiga there is such software available :-)
I have a Pentium 133MHz from a similar era. It was working until there was a power supply problem and the magic smoke, so probably something well within your skills. Maybe I should send it to you for another entertaining video?
@@SireSquish That's actually a pretty good match for the channel. I used to repair Compaq laptops back in the day as my day job :) Feel free to send me an email if you are interested in donating the Compaq. Thanks! epictronicsyt@gmail.com
@@SireSquish Hi! Am I missing an email from you? Unfortunately, there is nothing in my spam folder. Something must have gone wrong with the email :( Could you try to resend it? Thanks!
If you hadn't found a "proper" simm slot replacement you could have swapped out slot 4 and put the "wrong" one there instead. Then it will flip in the wrong way, but it won't hit anything.
26:40 I've done a bit of floppy repair work in the past so I know from experience, yes it's difficult to remove but the key is that screw has a LEFT HAND thread so you have to turn it the opposite way you would turn a normal screw to get it out ;-)
Every SIMM slot in my P70 is broken. Someone before me actually hot glued wedges of wood between the SIMMs to hold them in place. I haven't even attempted to fix it because it works and I don't want to tempt fate!
haha, I have actually seen a picture online of the "wedged wood" hack. Maybe, it was a common fix. Just leave it in, It's a period-correct fix :)
TIL: Solder Wick dries out! Totally makes sense, just never thought about it. Thanks!
That explains a lot lmao. I hadn’t used any of my soldering stuff from late 2019 to early 2023 (I wonder what was going on in the world then that kept me away 🤔) and by ’23 the solder wick was super uncooperative!
3D printing services from PCBway are nice but there's something super neat about printing a part, realizing it needs to be slightly different, and then just changing the model slightly in the slicer and just printing it again :3
I'm saving up for a printer :)
@@Epictronics1 go for bamboo labs, that thing is overengineered - it even uses Lidar to check the plate and the print ❤
I appreciate that you don't just replace components and solder, but take the time to read data sheets and probe signals as a true professional.
I guess, I should have brought out the scope earlier :)
Saved by the data sheet. Thankfully it was a common enough part to have an easily found datasheet. There are so many chips where it is almost impossible to find a data sheet now. Also a lesson learned check your voltages before desolding the chip. Though without desoldering the chip you wouldn't have known which trace was vcc and needed fixing. In the future for drives that don't spin. If you power the drive and assert the drive select and motor on signals on the cable the drive should spin so you don't need to actually connect to a working system to test the motor. For a proprietary cable like this drive unless you find the pin out it might be difficult to do though.
Those screws are reverse screws, that's why.
I really enjoyed seeing you fix that floppy drive. We've been in these phases of just trashing so many things that I just accumulate spare storage and optical drives and pretty much recycle the rest...it's nice to see these relics get some real attention! If we had kept all the old machines we would be swimming in them.
Thanks! I love my floppies :)
Migy have been cool to colour match those keyboard retaining pegs with the floppy disc eject button colour 😉🤷♂️
Hi Epictronics, what a nice machine the PS/2 P70. It was a great system for his time. I have lot fun with repair this machines. Greetings from Steven from the Netherlands
Thanks!
Opening this keyboard reminds me of the insanely difficult process to open another IBM keyboard: the Model M2. I had to use countless guitar picks to keep a bunch of plastic clips (on the edges and also all over the middle of the keyboard) pried open while trying to pull the top case/plate out... Traumatizing stuff! XD
Yeah, I have fixed a few of those. It's nerve-wracking but worth it. The M2 is sweet to type on!
@@Epictronics1 Definitely worth it! Basically a smaller Model M (that takes 1/3 less space on the desk).
I cheered louder than you did when the drive spun. Nice work! 🎉
I had to edit out some of my happiness haha, it was too much for YT lol. Thanks!
I would have used the grinding pen to remove the corrosion on the chip legs so that the solder could "bite" on to fresh metal. Also any PCB tracks that have the black spots on them need to have the solder mask removed and cleaned with a mild acid to remove the corrosion that has seeped under the solder mask. If you do not do this the trace will fail again some time later. I noticed this under the motor driver chip and around the C5 silk screen print on the PCB. Make sure to tin or use solder mask paint on all exposed copper traces to prevent further oxidation from the air after cleaning up the corrosion. You may want to run a thin wire to repair the damaged track as the solder blob is not very mechanically strong and may fail later (also it does look a bit ugly). You should add some flux to the solder brad before using it as that will make it wick better. If you were worried about damaging the motor with the hot air you could have covered it with a metal shield to deflect the heat such as aluminum foil. Although I would not be super concerned about it as when the magnets in the disk cooled down they should regain their magnetism. I have a old Weller soldering iron that uses a magnet in the soldering tip to control the temperature of the iron and it works quite well. When the iron get to temp the magnet demagnetizes and signals to the base station to kill the power to the element. When it cools down enough it re-magnetizes and turns the element back on again.
Yeah, I probably should have removed the solder mask and tined the traces for sure
After watching your videos, I have deduced that your favourite tool is "more flux"! :)
There isn't much you can't fix with just more flux :)
Motordriver, just a tipp: Reflow with leaded solder, use solder braid to remove as much as you can, reflow with solder, use solder braid, resolder, done. Leaded solder is far enough to use and even to prepare for rework by hot air.
I am still shocked, even knowing that was a 'rental' system, as to how clean that keyboard (really the whole system) is. What a job though, taking that keyboard apart. Great work on the drive, who would have known?!?!
Yeah, I've restored so many dusty and smelly IBMs. This machine is a joy to restore :) Thanks!
Finding that broken trace was unbelievable! It's always the last thing you check. Lol great work after the 2nd boot I think I would have pulled all but 1 stick of ram lol
Haha, yeah, I almost removed the RAM several times during the tests, but I didn't want to stress those plastic tabs!
Can't wait to see this bloody thing working, Roman!
Thank you for showing me a continuation to a PS/2 I would be interested in ♥
We're getting close now. Just a few more things to repair, upgrade, and hack :)
Very cool! Plot twist at the end, it works!
Sometimes, even I get lucky :D
Epic work! So glad to see the motor spin 😁 let's hope the drive can read and write too! 🤞
Thanks :)
If you want to un-Loctite a screw, an impact screwdriver is a very useful tool, since Loctite isn't designed to take shock load. A sudden torque on the screw will break it loose.
Depending on where you are in the world, this solution may or may not work for removing the stuck screw that holds the motor on. A very good solvent for glue, primarily for cyanoacrylate (super glue) but also works on some extent for epoxy: nitromethane. Yes, the stuff they use in racing fuels. I keep a little dropper bottle of it in my work kit, together with the deoxit and the silicone oil. In the US it is legal to buy (though not easy to find). In other parts of the world it may not be - definitely in Europe it isn't. Too bad because it's a very useful tool to have.
I'll check. Thanks!
Always happy whenever you drop a new video! I really enjoy how low-key educational they are simply by how you explain and show things in a way that I find easy to follow.
Thanks :)
To remove locktite - heat. More heat, obviously :)
Oh no, the struggle with floppy drive... I just swapped the original drive to Sony MFP920 and modded floppy cable. Eject button is of course different but it did work nicely.
That drive!!!! I have a similar issue, but the motor needs a small nudge to get going but the drive is still not able to boot.
I temporarily gave up and put a Mitsubishi drive instead, cut the translucent plastic insulation sheet at the back and massaged the connector to fit on the opposite side. The Mitsubishi is known to be more reliable anyway.
If only I could get that locktite off!!!
Hmm, I wonder if you could spray some deoxit in underneath the motor to fix it?
@@Epictronics1 No. I had a drive with exactly the same fault, nudge it and it works. The problem is the chip UNDER the flywheel is partially bad and some of the motor windings are not being driven. The fix is to replace the chip.
Next time you need to desolder a chip like that, you might want to try wrapping a thick piece of copper wire around it, then soldering it to all the pins, then heating it up with the iron until all the solder is molten and lifting or flicking it off. Haven't tried it myself, but I've seen this technique used before, and it seems to work pretty well, although it does use a lot of solder.
I may give that a try! Thanks
Incredible patience! Such a shame that so many circuit boards get damaged by leaking electrolytic caps.
So many boards to save, so little time!
Ah, I used to have a P70 as well. Got rid of it because it had broken SIMM slots. Wish I had kept it since by now I could find the resources to replace them.
I'm pretty sure you can safely disassemble the motor assembly on such a floppy drive.
To defeat stubborn loctite use heat. Use the tip of your soldering iron to heat the screw up as hot as you possibly can. Then it should come out easily.
I'll give it a try, thanks
Nicely done! That is a tiny crack!!
Thanks!
You should be able to get that motor out. It's likely those 4-5 screws on the trace side (the motor 'board' is actually traces printed on a steel substrate, I believe) and then around the spindle on the other side? Those blue SMT chips with no markings, I would tend to think they're zero-ohm jumpers given the 'J' next to them on the plate.
You remove Loctite with heat...
What you can do is get a crap soldering pencil. 100 watts if possible. Find a Phillips screwdriver that has a shaft the same diameter as the crap soldering pencil. Cut off the screwdriver shaft as short as you're willing to do, use it in the crap soldering pencil as a soldering tip, and let it heat up. Use the entire crap soldering pencil with the screwdriver tip installed as a hot screwdriver. You may try using the hot air rework to help get the screwdriver tip nice and hot in addition to the crap pencil iron.
Nice fix! Looks like I need to do my floppy drives as well. Even though I am going with a Gotek and the adapter board, I'll clean and recap them. I have some vanilla P70s as well as a GE WorkMaster.
Sweet. I'd love to find a WorkMaster someday! If you're not going to use the drives, you could just remove the caps
@@Epictronics1 Thanks! Looks like they are getting scarce! We used to use them for programming PLCs (initially the GE Series Six PLC, and later on, the GE 90-30 and 90-70 PLCs).
At one point we were literally throwing the WorkMaster I units (IBM 5155 PCs) away. I "rescued" the outer cover of one and repurposed it as my "$10,000 trash can".
The venerable old Series Six is almost gone, so these aren't all that useful these days. Certainly not for programming PLCs. :) I doubt that I will install Windows on mine since it didn't come with Windows from GE. A fresh copy of DOS and then LM6 and I'll be all set. :)
As for the caps, I had thought of that, and then realized that I would probably never remember what the values of the caps that I removed were (I'm sure that it's written down somewhere). :)
@@MrWaalkman Yes, for sure. It will be easy to find the correct value in the future. I guess, you could write it on a sticker to save time. They all have a designator, like C1, C2, and so on
Even tho I don’t have much for soldering skills, seeing a broken trace I would just run a budge wire to connect such a short run.
Rewatching & commenting again since I can see this ended up being a reupload. I remarked on the ChipQuick not being so quick to work.
Sorry about that!
Removing loctite, heat is the best but you need to heat it to something like 200C.
Methylene Chloride or acetone might work depending on what type of thread lock it is.
Thanks
Such a great channel! I also love the laptop.
Thanks!
Kapton tape to the rescue! (Of the floppy drive motor)
I should have thought of that! Thanks
The mystery blue components are jumpers. They have a letter "J" written next to them.
Possibly Goof Off Pro or a Limonine based solvent.
You might want to tape the key switches in the pushed position, when prying.
The devil always lays in the details... When I saw that 4 Volt in the little scope's screen I said no way that voltage is correct! It should be 12... That may indicate also that the previous driver Hitachi chip may be also working and you are really lucky that the crack was not below the chip.
Great project on a very interesting machine maybe there is a BIOS that has a faster RAM counter out there?
Anyways excellent video as always, keep up! Cheers from Greece
Thanks! Yes, the other chip is now installed in another drive and working just fine :)
Do you know that the screw is maybe other way around? If you try to open it and it is threaded the other way, you try to screw it on even more. They often do those "wrong screws"/Clockwise/counterclockwise because it would spin free with the movement of the motor.
I never thought of that! Thanks
Wow, that keyboard socket looks almost like a USB-E type or eSATA.
Removing the motor board is definitely a bad idea, I’ve removed a hub motor assembly and after reassembling wouldn’t read disks unless I loosened the screws and move the motor board around until disks read correctly.
The board has a zero track sensor that has to be re-set correctly. But it's easy to fix using some calibration software. At least on Amiga there is such software available :-)
@@g4z-kb7ct I'll check, thanks!
Great video
Thanks :)
@@Epictronics1 thanks
Those floppy drives have righty loosy screws. Reverse thread.
Oops.. Thanks :)
It looks like you need to 3D-print some SIMM slots
It would have been interesting to see a thermal image of the broken trace, because it drops almost 8 volts.
Never thought of that. Maybe, we could have seen the fault with the thermal camera?
@@Epictronics1 : I'm by no means an electronics expert, but dropping 8 Volts should result in some significant heat.
Doesn’t acetone remove loctite? It certainly removes superglue.
I may try it, thanks
I'm very experienced with removing Loctite from my hands but can't say I know how to remove it from anything else.
Use heat to release Loctite, if that's what it is.
I have a Pentium 133MHz from a similar era. It was working until there was a power supply problem and the magic smoke, so probably something well within your skills. Maybe I should send it to you for another entertaining video?
Sounds like fun :) What machine is it?
@@Epictronics1 That took some doing. But I found it in one of my many storage boxes. It's a Compaq LTE 530. What's the best way to get in touch?
@@SireSquish That's actually a pretty good match for the channel. I used to repair Compaq laptops back in the day as my day job :) Feel free to send me an email if you are interested in donating the Compaq. Thanks! epictronicsyt@gmail.com
@@Epictronics1 done. Check your spam folder?
@@SireSquish Hi! Am I missing an email from you? Unfortunately, there is nothing in my spam folder. Something must have gone wrong with the email :( Could you try to resend it? Thanks!
Could them 'mystery components' be zero ohm resistors?
Quite possible
Does that low melt solder contain gallium? If it does, it may cause problems when in contact with aluminium.
I'm gonna have to check, thanks
What's left to do on this PC after fixing the drive and keyboard?
Display, and FDD lock. Reassembly and a mystery attempt...
If you hadn't found a "proper" simm slot replacement you could have swapped out slot 4 and put the "wrong" one there instead. Then it will flip in the wrong way, but it won't hit anything.
Yeah, that was my plan "B", but I was lucky and found this slot on a donor board :)
Is the soldering tip from your FNIRSI soldering station grounded/ESD safe?
How much swearing did you do when you pulled apart the keyboard? :)
If I hadn't turned the camera off, it would have been about one hour of just beebs in this video lol
i found a pc at a flea market with all the simm memory soldered with wire where the slots should have been (i didn't buy it)
Haha, I would have picked it up :)
@@Epictronics1 i should have taken a picture :)
26:40 I've done a bit of floppy repair work in the past so I know from experience, yes it's difficult to remove but the key is that screw has a LEFT HAND thread so you have to turn it the opposite way you would turn a normal screw to get it out ;-)
I may have tightened it pretty hard now... lol