Even though I made this video to help people know where the screws go back, it's still a good idea to screw them partially back into place during disassembly. Then you know exactly where they go!
@@JDW- That a super simple yet powerful idea. Can't remember how many times I messed up with screws, even taking precautions. I recently watch some watch repairs, and noticed they tend to put back screws on complex watches as well.
Great Video as always. Just a thought on measuring (and selecting) the caps: As this is a switch mode power supply, the caps on the secondary side get charged with a very high frequency in the kiloherz range (thus they need to be low esr) so they should be measured with the 100kHz setting while the primary side ones (the >300V ones) can be measured at the double of your line frequency (100/120Hz - i know japan uses both) as this is what they need to cope with behind the rectifier. Thus they also don't need to be low esr ones. Measuring the secondary caps in the low frequency range can make them appear healthier then they are for the job they need to do.
Fantastic James! Thank you-I'm ordering my Mouser cart (x4) ASAP! I'm glad you did not have any ESR issues this time. I liked the black & white inset graphics with the caps highlighted-makes what you were showing very clear. Also, thank you for showing the expected voltages & where to measure. All four of my units spin up, but none mount. Now I can test for voltage issues before I start. Hopefully this fixes them.
Thank you for all the time and effort you put into you great videos and into all the carts you always make. I ordered my Mystic stereo mod caps from your cart at Mouser and I’m about to order this cart today for my HD20. Keep up the great videos!! Maybe a PPC CC mod down the road.
I have the 128K ROMs installed, with the Kay Koba ROM-inator AND I also have Kay Koba's FAT MAC SWITCHER, which let's me choose 128K or 512K at a flip of a switch. I have videos on both of those excellent add-ons. I highly recommend them both for every Mac512K.
Wow, Gavin. I didn't know that. So the father of the original Macintosh Finder returns to Apple. Very interesting. One can't help but wonder what he is working on now.
I am new to the restoration world and enjoy learning about fixing old electronics like vintage Macs. I wonder if most parts machines that a person might buy are restorable assuming no major capacitor leakage that damages the PCB. Thanks again.
Professor Lund, thank you for the excellent question. The short answer is "sometimes." 🙂 An Apple "parts machine" is often sold by someone who has no idea how to repair a machine, or who has no desire to do the job. There are parts machines sold on EBAY where a repair is surprisingly easy - merely obtaining a working battery for a Macintosh Portable, for example, often brings the machine to life. You might even find a Macintosh SE for a cheap price only because the seller thought it was bad because they didn't realize the screen brightness was turned down all the way. But there are also machines sold which have been mostly destroyed by an exploded PRAM battery. That damage is worse than even leaking capacitors. And of course, many machines have both leaking caps and an exploded battery. When the guts of a PRAM battery are sprayed everywhere, PCB traces become severed over time, legs of IC chips become eaten away, and most metal becomes horribly rusted. Even so, there is almost always something inside a destroyed parts machine which can be used in a different vintage computer which has far less damage. In terms of restoring a very damaged machine though, I am pleased to report that "battery bomb" computers (which have PCBs that are no longer usable) have served as the inspiration for reverse engineering geniuses like Kai Robinson (at the TinkerDifferent forum) and Bolle (at the 68kMLA forum) to create brand new motherboards for the Mac Classic, Mac SE, and Mac SE/30. Many components on a battery bombed motherboard remain functional and can be desoldered and moved to one of these new boards. Unusable parts on the battery-bombed board can often be sourced from Mouser, DigiKey or even from China. There are even small organizations like "CayMac Vintage" which will take your old SE/30 motherboard and move components to a new Bolle edition SE/30 motherboard. Building an entire motherboard is not impossible to do yourself (I have a video tutorial about how to do the SE Reloaded motherboard, for example), but having the right soldering and desoldering tools is paramount. Even then you would also need lenses or microscopes to see the smaller SMD components more easily (for a Mac Classic or SE/30 motherboard). Lastly, there are some machines which tend to be harder to restore than others due to more leakage or battery bomb issues. When you are considering the purchase of a vintage computer, I would recommend joining an online forum or FaceBook Group which pertains to that computer (e.g., Mac related groups). If you are thinking about buying a Macintosh Portable, for example, you can then ask "the experts" what are the most common problems. They will then tell you about the need for a working battery, the fact the Conner hard drive may be unusable, and that the motherboard needs to be recapped. They will then go on to talk about possible leakage from the 9V PRAM battery (near the main battery), and mention that the rubber feet on the bottom may be missing, You then will be better informed so as to decide if buying a machine with those potential caveats is worth it. For instructional repair purposes, obtaining machines that have mostly through-hole components like a Macintosh 128K, 512K 512Ke, Plus or SE are easier to deal with than surface mount (SMD) machines like the SE/30, Mac Classic, Classic II and newer. Best wishes!
to read/write from/to old macintosh HFS filesystems i use a linux machine(virtual machine or real hardware) i can read/write directly from the normal file browser. disk images need to be mounted as drives. but its by far the most fricrionless way to do it in my experience.
I'm 100% Mac-only and have been since 1984. (Yes, I'm rare.) So naturally, I prefer a Mac solution to read HFS disks, and the ideal is to be able to do that on a modern Mac, which means Apple Silicon. Unfortunately, none of the modern solutions to that problem work for me, hence, my only way to use the Tash20 is to use my FloppyEMU to move files from my modern Mac to the real HD20, then copy those files to the Tash20. I do not like that at all. The Tash20 needs a redesign to allow the SD card to be formatted in the way pretty much every single SD card based drive is formatted (i.e., not HFS). MacSD, BlueSCSI, FloppyEMU -- none of these give me trouble. Only the Tash20 has an HFS-formatted SD card. It's really quite frustrating. Why not use the FloppyEMU instead? Well, I do. But the Tash20 is neat because its cheap, tiny, simple, and it doesn't get in your way. No cables either. It's a super neat product if you can get around that HFS formatted SD card.
@@JDW- This sis something that I find unpleasant when doing data backup on vintage Apple products at my computer store. I've had several customers bring in old floppy disks or an ancient machine and they need files off of it. With an IBM compatible machine, I can take disks from 30 years ago, put them in a USB floppy disk, and pull stuff off with no trouble, barring bit rot. Apple machines are quite a bit more interesting to do the same task.
@@ralphshoop8822 Vintage Macs have gone through 3 eras of 3.5" floppy disks: (1) 400K SSDD, (2) 800K DSDD, and 1.44MB 2HD. The 400K and 800K disks beat the IBM PC in terms of storage thanks to Apple's choice of GCR variable speed. But that broke compatibility with PC disks. You can read PC disks on Macs with special software, depending on the model, but reading Mac disks outside a vintage Mac can be troublesome. It's therefore best to have a Mac Plus or SE FDHD or SE/30 or Mac Classic to be able to read the old 400K and 800K disks properly. You can then convert them to disk images via ShrinkWrap, Disk Copy, etc., then attach a FloppyEMU to the vintage Mac, copy the images to the FloppyEMU, then put the SD card of the FloppyEMU into your modern computer (PC or Mac) to copy off the images and save them to a server or send them to someone by email. Of course, you can download images from Macintosh Garden, save them to your FloppyEMU, attach the FloppyEMU to your vintage Mac, then copy the images to a real floppy. It all works rather well thanks to the FloppyEMU and the modern tech it provides. Just imagine having one back in the day!
In that case, it must be Acrylic Resin, brushed on at the factory. It doesn't feel rubbery like Silicone Resin would be, and it comes of fairly easily with IPA and a toothbrush, which implies it isn't Urethane Resin. It would also explain why the copper side of these PCBs tend to be in good shape after 37 years. But I must say, the smell is pretty powerful. You can smell it even before you try to remove it with IPA, but even more so after you've removed some of it.
As for the (very) slightly higher noise, your second measurements were done out of the case, so in a slightly different electrical environment. As you mention, I'm not sure this is very relevant.
The noise differences were close enough so the differences are not relevant. I did such extensive testing because I had issues with the HD20SC PSU recapping, as shown here: ua-cam.com/video/Qof-Wjj_rWI/v-deo.htmlsi=sVcGDeLoH8MsBrak&t=2481
@@WelcomeToMarkintosh Although I like Mouser, they are also a band of idiots at times. It was just in stock, and now it says "non-stocked"! Totally and utterly insane. Mouser loves to play those crazy games. I just swapped it out with pretty much an identical cap. You can now buy multiple carts in confidence. Sorry for the trouble!
You just need to measure the voltage. If the voltage is right, then it could be the stepper motor is not spinning up the drive. You can read Dog Cow's experience lubricating his Rodime here, although I would only recommend the stepper motor and not the ball bearing in the middle of the large spindle: macgui.com/news/article.php?t=445
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The care and precision with which you approach these repairs and the video editing is super satisfying to watch!
Also, showing the location of screws or components is really a very good idea.
Even though I made this video to help people know where the screws go back, it's still a good idea to screw them partially back into place during disassembly. Then you know exactly where they go!
@@JDW- That a super simple yet powerful idea. Can't remember how many times I messed up with screws, even taking precautions. I recently watch some watch repairs, and noticed they tend to put back screws on complex watches as well.
Great Video as always. Just a thought on measuring (and selecting) the caps: As this is a switch mode power supply, the caps on the secondary side get charged with a very high frequency in the kiloherz range (thus they need to be low esr) so they should be measured with the 100kHz setting while the primary side ones (the >300V ones) can be measured at the double of your line frequency (100/120Hz - i know japan uses both) as this is what they need to cope with behind the rectifier. Thus they also don't need to be low esr ones.
Measuring the secondary caps in the low frequency range can make them appear healthier then they are for the job they need to do.
Fantastic James! Thank you-I'm ordering my Mouser cart (x4) ASAP! I'm glad you did not have any ESR issues this time. I liked the black & white inset graphics with the caps highlighted-makes what you were showing very clear. Also, thank you for showing the expected voltages & where to measure. All four of my units spin up, but none mount. Now I can test for voltage issues before I start. Hopefully this fixes them.
Thank you for all the time and effort you put into you great videos and into all the carts you always make. I ordered my Mystic stereo mod caps from your cart at Mouser and I’m about to order this cart today for my HD20. Keep up the great videos!! Maybe a PPC CC mod down the road.
Another perfect video :) I really like your detailed methodology and you attention to details. Thank you.
Thank you for your very kind words, Philippe!
Always fantastic My Friend!
Thank you, Michael.
Almost forgot-That was awesome to learn you were on a 128! I had no idea you could do that! So you have a 128Ke Half-Fat Mac lol
I have the 128K ROMs installed, with the Kay Koba ROM-inator AND I also have Kay Koba's FAT MAC SWITCHER, which let's me choose 128K or 512K at a flip of a switch. I have videos on both of those excellent add-ons. I highly recommend them both for every Mac512K.
@@JDW- Oh yeah-I forgot about that! Very cool.
Nice one James. Interesting to note that Bruce Horn (Finder credits @ timestamp 36:28) recently returned to Apple...
Wow, Gavin. I didn't know that. So the father of the original Macintosh Finder returns to Apple. Very interesting. One can't help but wonder what he is working on now.
I am new to the restoration world and enjoy learning about fixing old electronics like vintage Macs. I wonder if most parts machines that a person might buy are restorable assuming no major capacitor leakage that damages the PCB. Thanks again.
Professor Lund, thank you for the excellent question. The short answer is "sometimes." 🙂
An Apple "parts machine" is often sold by someone who has no idea how to repair a machine, or who has no desire to do the job. There are parts machines sold on EBAY where a repair is surprisingly easy - merely obtaining a working battery for a Macintosh Portable, for example, often brings the machine to life. You might even find a Macintosh SE for a cheap price only because the seller thought it was bad because they didn't realize the screen brightness was turned down all the way. But there are also machines sold which have been mostly destroyed by an exploded PRAM battery. That damage is worse than even leaking capacitors. And of course, many machines have both leaking caps and an exploded battery.
When the guts of a PRAM battery are sprayed everywhere, PCB traces become severed over time, legs of IC chips become eaten away, and most metal becomes horribly rusted. Even so, there is almost always something inside a destroyed parts machine which can be used in a different vintage computer which has far less damage.
In terms of restoring a very damaged machine though, I am pleased to report that "battery bomb" computers (which have PCBs that are no longer usable) have served as the inspiration for reverse engineering geniuses like Kai Robinson (at the TinkerDifferent forum) and Bolle (at the 68kMLA forum) to create brand new motherboards for the Mac Classic, Mac SE, and Mac SE/30. Many components on a battery bombed motherboard remain functional and can be desoldered and moved to one of these new boards. Unusable parts on the battery-bombed board can often be sourced from Mouser, DigiKey or even from China. There are even small organizations like "CayMac Vintage" which will take your old SE/30 motherboard and move components to a new Bolle edition SE/30 motherboard. Building an entire motherboard is not impossible to do yourself (I have a video tutorial about how to do the SE Reloaded motherboard, for example), but having the right soldering and desoldering tools is paramount. Even then you would also need lenses or microscopes to see the smaller SMD components more easily (for a Mac Classic or SE/30 motherboard).
Lastly, there are some machines which tend to be harder to restore than others due to more leakage or battery bomb issues. When you are considering the purchase of a vintage computer, I would recommend joining an online forum or FaceBook Group which pertains to that computer (e.g., Mac related groups). If you are thinking about buying a Macintosh Portable, for example, you can then ask "the experts" what are the most common problems. They will then tell you about the need for a working battery, the fact the Conner hard drive may be unusable, and that the motherboard needs to be recapped. They will then go on to talk about possible leakage from the 9V PRAM battery (near the main battery), and mention that the rubber feet on the bottom may be missing, You then will be better informed so as to decide if buying a machine with those potential caveats is worth it.
For instructional repair purposes, obtaining machines that have mostly through-hole components like a Macintosh 128K, 512K 512Ke, Plus or SE are easier to deal with than surface mount (SMD) machines like the SE/30, Mac Classic, Classic II and newer.
Best wishes!
to read/write from/to old macintosh HFS filesystems i use a linux machine(virtual machine or real hardware) i can read/write directly from the normal file browser. disk images need to be mounted as drives. but its by far the most fricrionless way to do it in my experience.
I'm 100% Mac-only and have been since 1984. (Yes, I'm rare.) So naturally, I prefer a Mac solution to read HFS disks, and the ideal is to be able to do that on a modern Mac, which means Apple Silicon. Unfortunately, none of the modern solutions to that problem work for me, hence, my only way to use the Tash20 is to use my FloppyEMU to move files from my modern Mac to the real HD20, then copy those files to the Tash20. I do not like that at all. The Tash20 needs a redesign to allow the SD card to be formatted in the way pretty much every single SD card based drive is formatted (i.e., not HFS). MacSD, BlueSCSI, FloppyEMU -- none of these give me trouble. Only the Tash20 has an HFS-formatted SD card. It's really quite frustrating. Why not use the FloppyEMU instead? Well, I do. But the Tash20 is neat because its cheap, tiny, simple, and it doesn't get in your way. No cables either. It's a super neat product if you can get around that HFS formatted SD card.
@@JDW- This sis something that I find unpleasant when doing data backup on vintage Apple products at my computer store. I've had several customers bring in old floppy disks or an ancient machine and they need files off of it. With an IBM compatible machine, I can take disks from 30 years ago, put them in a USB floppy disk, and pull stuff off with no trouble, barring bit rot. Apple machines are quite a bit more interesting to do the same task.
@@ralphshoop8822 Vintage Macs have gone through 3 eras of 3.5" floppy disks: (1) 400K SSDD, (2) 800K DSDD, and 1.44MB 2HD. The 400K and 800K disks beat the IBM PC in terms of storage thanks to Apple's choice of GCR variable speed. But that broke compatibility with PC disks. You can read PC disks on Macs with special software, depending on the model, but reading Mac disks outside a vintage Mac can be troublesome. It's therefore best to have a Mac Plus or SE FDHD or SE/30 or Mac Classic to be able to read the old 400K and 800K disks properly. You can then convert them to disk images via ShrinkWrap, Disk Copy, etc., then attach a FloppyEMU to the vintage Mac, copy the images to the FloppyEMU, then put the SD card of the FloppyEMU into your modern computer (PC or Mac) to copy off the images and save them to a server or send them to someone by email. Of course, you can download images from Macintosh Garden, save them to your FloppyEMU, attach the FloppyEMU to your vintage Mac, then copy the images to a real floppy. It all works rather well thanks to the FloppyEMU and the modern tech it provides. Just imagine having one back in the day!
That's conformal coating. It gets sticky when it dissolves from the alcohol.
In that case, it must be Acrylic Resin, brushed on at the factory. It doesn't feel rubbery like Silicone Resin would be, and it comes of fairly easily with IPA and a toothbrush, which implies it isn't Urethane Resin. It would also explain why the copper side of these PCBs tend to be in good shape after 37 years. But I must say, the smell is pretty powerful. You can smell it even before you try to remove it with IPA, but even more so after you've removed some of it.
@@JDW- Haha, indeed, some conformal coatings are smelly, but from my understanding the odor comes mostly from the secondary ingredients.
As for the (very) slightly higher noise, your second measurements were done out of the case, so in a slightly different electrical environment. As you mention, I'm not sure this is very relevant.
The noise differences were close enough so the differences are not relevant. I did such extensive testing because I had issues with the HD20SC PSU recapping, as shown here: ua-cam.com/video/Qof-Wjj_rWI/v-deo.htmlsi=sVcGDeLoH8MsBrak&t=2481
Looks like we've started a RUN on HD20 Caps at Mouser-one of them is already on back order! lol.
Which cap? I just now checked after reading your comment, but none are showing backordered.
@@JDW- it's the 10volts 1200uF AEC-Q. I ordered 4 & it told me 3 were back ordered. I did 4X on everything, that's the only one that says B.O.
@@WelcomeToMarkintosh Although I like Mouser, they are also a band of idiots at times. It was just in stock, and now it says "non-stocked"! Totally and utterly insane. Mouser loves to play those crazy games. I just swapped it out with pretty much an identical cap. You can now buy multiple carts in confidence. Sorry for the trouble!
@@JDW- Yeah, as soon as I edited my order to 4, I got the message. I may have gotten the last one.
@@WelcomeToMarkintosh There are 1300pcs of the replacement cap I just now swapped in place of the backordered cap.
I’ve got one but unfortunately I think the hard drive is bad
You just need to measure the voltage. If the voltage is right, then it could be the stepper motor is not spinning up the drive. You can read Dog Cow's experience lubricating his Rodime here, although I would only recommend the stepper motor and not the ball bearing in the middle of the large spindle: macgui.com/news/article.php?t=445
My Rodime died in 1997.
Could just be the stepping motor froze and requires oil. If you still have the drive, you could try that.