Jump to content


  • Content Count

  • Joined

  • Last visited

Everything posted by JDW

  1. Yes, even the Macintosh 128k/512k KEYBOARD needs to be recapped: But does it really need to be 63V? Here's the keyboard schematic, with the 1uF cap showing in the upper right area nearest U2: And U2 is the 74LS123 shown here: Sure, I can find a Mouser $3.23 replacement, but why is the stock cap rated at 63V? Is it because people might be stupid and connect the keyboard to a phone jack, or is there some other reason? The reason I even wonder about this is because if lower voltage 1uF caps can safely be used in this keyboard, then more replacement options present themselves that are better and cheaper too. I look forward to your insightful replies!
  2. @LaPorta What I do is use a thick black Sharpie pen to handwrite the replacement date clearly on one of the big, easily noticeable caps, and that serves as a note to me (or those two whom I sell something) that ALL the caps were replaced on that date. Paper notes get lost but a pen-mark on the cap won't go away.
  3. Here's a photo of my recapped IIgs keyboard, and note the hot glue around the ADB connectors that I added is important to prevent broken solder joints: And here's a photo of the Apple Mouse G5431 with stock capacitors (3pcs). Width and Height of replacement caps is a very important consideration because there's not a lot of space. Suffice it to say, if you've been having tracking issues even though your rollers are clean, it could be the caps! Normally you want to spec Tantalum caps higher than electrolytics to avoid a fiery explosion in the event of over-voltage, but ADB supplies only 5V. So you could safely use 16V radial dipped tantalums without problem, and at that voltage rating they should fit fine.
  4. There’s no guarantee that the chosen replacement fluid filled capacitor will last as long. And 25 years hence, I will be too old to want to replace it again, probably. And that’s precisely why tantalum is a good choice because 25 years from now you won’t need to replace it again. By the way, I first started replacing capacitors in keyboards when I experienced a problem with the IIgs keyboard attached to my SE:30. Sometimes I would be using the computer and typing on it and nothing would happen. I opened it up one day only to find fluid filled capacitors inside. I replaced them with tantalums and the problem was solved.
  5. Arguably, this is but one capacitor inside a keyboard. And if it leaked, it would leak on the top side of the PCB where there are no traces. It would not harm anything, most likely. ESR would slowly rise until the capacitor is no longer usable due to leaked or evaporated electrolyte. And while no reports have been made to date about these keyboards, not everyone knows why these keyboards go bad and may just replace them in silence without reporting anything. Also, I would suspect that with it now being 35 years or so since manufacture that we would eventually see problems pertaining to this capacitor because no fluid-filled electrolytic capacitor lasts forever. That's the key here. No fluid filled capacitor lasts forever, and after 35 years, you're lucky indeed if you still have half of the original electrolyte in there. So let's forget all the "if it ain't broke, don't fix it" thinking for a moment and consider replacements in light of what @cruff and I have already said. 6.3V is probably a reasonable rating for an electrolytic replacement since this is a 5V IC it is connected to. However, it's silly to replace it with another fluid filled cap for reasons already stated. It therefore makes the most sense to use either ceramic or tantalum, since both are solid electrolytes that will indeed last as long as the circuit board itself. Axial ceramics will fit but they cost a lot more than tantalum. I checked lower voltages for the 1uF tantalum cap on Mouser. Surprisingly, those actually cost more. And since over-voltage on tantalum caps results in fire and burning, you always get a rated voltage much higher than an electrolytic. At least twice. So 10V would be pushing it. I'd feel safer with 15V or higher. But again, the axial tantalum caps on Mouser are all about $1 each, so one might as well get the 50V Vishay 173D105X9050VWE3. If the price is roughly the same and if it fits, get the best part. After all this discussion, there will still be some who won't replace the cap until it dies. I think that's probably ok in this case for reasons already stated. But for those who are doing recapping jobs like I am right now, we put together a bunch of caps to recap various things, which is a good idea as a sufficiently large enough order could qualify you for free shipping. And when you live outside the USA like I do, that matters. Thank you for the input! And if anyone reading this has experienced a bad cap in a Mac 128k or 512k or Plus keyboard, please report that here. Surely there must be at least one of you out there.
  6. It is not malfunctioning. But I've had SE/30 motherboards that had never been recapped and seemed to work OK, and all the while the electrolyte was leaking out and slowing eating traces. The point here is that just because something is working doesn't mean it shouldn't be recapped, especially when the electrolytic capacitor in question is 35 years old.
  7. 28 views of this thread as of the time of this writing but no replies, and here I am back to talking to myself again. According to the Operating Rules on page 3 of this 74LS123 data sheet, the 1uF capacitor in combination with the 200k-ohm resistor forms a timing circuit that determines pulse width. Since the 1uF capacitor sits behind a 200k resistor tied to 5V, it's not clear why Apple's 1uF capacitor is rated at 63V. Certainly, the capacitor would have been cheaper had they used a lower voltage rating. And even though the positive side of that 1uF capacitor is also tied to the Rext/Cext pin of the 74LS123 chip, it's not possible that pin will see anywhere close to 63 volts. Why then did Apple choose a 1uF capacitor rated at 63V? Well, we know that the higher the voltage rating of an electrolytic capacitor the lower the ESR, and since 1uF electrolytic capacitors have a large ESR even when brand new, choosing 63V (probably the highest voltage available back in 1983) would have yielded the lowest ESR. But that is just my speculation. And why Apple would have wanted lower ESR is not clear because the 74LS123 data sheet makes no mention of capacitor ESR, and I have checked several 74LS123 data sheets even as far back as 1983. So I don't really know what to think if that voltage rating choice is NOT tied to ESR. So the question remains, what capacitor should we use as a replacement? Since that aforementioned datasheet says Tantalum capacitors can be used, it is a matter of choosing the voltage rating. The Vishay 173D105X9050VWE3 is a perfect length and diameter axial tantalum capacitor rated for 50V but can handle a surge voltage of 65V. It currently costs $1.17 at Mouser, which is fairly high but much lower than the $3.23 100V 1uF electrolytic I mentioned in my opening post. And because this $1.17 cap is Tantalum and rated at a fairly high voltage, the ESR would be less than the 63V electrolytic Apple uses, but yet not super-low like a ceramic capacitor would be. But again, I don't think the rated voltage matters in terms of voltage surges, because I doubt we'd even get double Vcc (10V) across that capacitor. So I would assume that an even lower voltage rated tantalum axial capacitor would suffice. However, going down to a 35V tantalum axial capacitor only drops the price to $1.06. And going to a 25V part only drops the price to $0.97. So we might as well choose the 50V rated Vishay tantalum I linked to. Why choose a tantalum rather than an electrolytic? Because we don't want to swap out an electrolytic replacement again 20 years hence. Even the best electrolytic caps will eventually dry out and/or leak. A tantalum capacitor will last the life of the keyboard. So I think I will go with the 50V Vishay cap, unless some of you present good reasons to avoid it. Feel free to share you thoughts. No, actually, please share your thoughts. I feel lonely talking to myself in this forum. Thanks.
  8. I'm in the planning process to recap the SONY PSU housed inside my Apple HD20SC external hard drive enclosure. (I might make a video.) I've got a Mouser cart filled with mostly Organic Polymer Aluminum Electrolytic capacitors for that PSU (see below), which have very low ESR down to between 12mΩ and 43mΩ. There are many benefits to low ESR capacitors, and the life rating on them is very high compared to regular aluminum electrolytics. But my concern is that the output of some switch-mode (switching) power supplies can ring if the ESR of the output capacitance is too low (as per the data sheets of many switch mode controllers), so do any of you have a schematic? If not, have any of you used a large number of Organic Polymer capacitors in your vintage Mac PSU recap jobs with success? (I'm asking about power supplies here. Non-PSU applications don't matter much. Mostly those cases are a decoupling/bypass caps which hold up the voltage in times of voltage dips, and those caps benefit from very low ESR.) Here's my Mouser list of mostly polymer caps: C226: 22uF 35V, D=5.2mm -- (Mouser: A759BQ226M1HAAE075) C202: 47uF 25V, D=5.2mm -- (Mouser: A750EK476M1EAAE040) C222: 47uF 25V, D=5.2mm -- (same as C202, so get 2pcs) C109: 150uF 400V, H=32mm, D=25.8mm -- (Mouser: 860021383023) C110: 4.7uF 350V H=32mm, D=12.8mm -- (Mouser: UPM2G4R7MHD) C210: 330uF 16V, D=8.1mm -- (Mouser: RL81C331MDN1KX) C215: 470uF 10V, D=8.1mm -- (Mouser: RNE1C471MDN1) C213: 22uF 100V, D=10.2mm -- (Mouser: A759MS226M2AAAE045) C124: 2200uF 10V, D=12.7mm -- (Mouser: UHE1C222MHD) C209: 2200uF 16V, D=12.7mm -- (just buy the same as C124, so get 2pcs) CR-35 daughter card: C181: 100uF 10V, D=8.1mm, H=13.5mm -- (Mouser: RNS1A101MDN1KX) C182: 100uF 10V, D=8.1mm, H=13.5mm -- (same as C181, so get 2pcs)
  9. Jeff, in light of how many replies I have received to date, it looks like you may be waiting a very long time! Not being a man given to much patience, I decided to post in the BadCaps forum too, which you can follow here: https://www.badcaps.net/forum/showthread.php?p=896663#post896663
  10. Hmmm... Only 6 views and nary a reply. Well, I shall talk to myself then... (Assuming @trag or @Bolle or @joethezombie or @techknight don't wish to join in.) Why consider recapping with solid organic polymer aluminum electrolytic capacitors? Because in addition to low ESR (which is sometimes very beneficial), they also offer longer life than fluid-filled electrolytic capacitors (in addition to the fact that the solid electrolyte of polymer caps won't leak). Have a look at this life chart: I suspect the ambient internal air temperature of even our upgraded Compact Macs won't exceed 65°C, hence the stark contrast between the expected life of polymer caps versus fluid-filled electrolytics. The main downside to polymer caps is their leakage current, which is often on order of a couple hundred microAmps to even just over 1mA. Most fluid-filled caps have leakage currents far lower -- maybe 20uA or less. But since we are not recapping battery powered machines here, the detrimental effects of polymer capacitor leakage is not so significant. Again, I look forward to hearing your thoughts. Thanks.
  11. Low End Mac mentions that any RAM configuration above 32MB is no specified by Apple and therefore there are no specific guidelines for higher configurations. I therefore am curious to hear from those of you who own 16MB SIMMs to see if you experience matches my own. I have an SE/30 with the stock SE/30 ROM and a CPU-socketed 50MHz Daystar 68030 Power Cache accelerator. When I fill all 8 RAM slots (motherboard RAM slots -- the Daystar card has no RAM), the SE/30 powers on with with the normal bong (although the bong sound is cut short a bit at the end for some reason) and I can confirm 128MB of RAM when I boot. But when I put only 4 of those 16MB SIMMs in Bank A or only 4 in Bank B (for 64MB RAM total), I get the chimes of death (full chime sound, not cut short) and see the following garbage on screen: This is true even with no ADB devices attached, no internal HDD, and the internal Floppy Drive disconnected. The motherboard, analog board and SONY PSU are all recapped. And nothing is in the PDS slot. Have any of you SE/30 owners had success filling only 4 slots (Bank A only or Bank B only) with 16MB SIMMs?
  12. Thank you for watching. I would say you are doing better than most. YouTube Analytics as of today shows the average view duration to be a mere 9 minutes on my 1 hour videos, and none of them currently have more than 410 even though they've been out a few months. It's somewhat disappointing. I guess our vintage Mac community is smaller than I thought, or even fewer people have an SE or SE/30 to care. (Perhaps I'm a bit spoiled on the 210,000+ views on my 2009 iMac Video Card Bake video.) But no matter, I don't make videos to make money. I've never made a cent off YouTube. I do it for the enjoyment of helping others who share my hobby. Glad to hear these videos could be of help to you, Neal!
  13. Yes. I include all the nitty gritty details in the text description under all my YouTube videos. Simple click SHOW MORE to expand that text on YouTube. And be sure to read all the descriptions under all my videos because they are all different. That text in combination with the video tells you pretty much everything you need to know. But after reading and watching if you do have a question, please post it under the video as it may be helpful for others. I read and reply to every single comment.
  14. I have recapping walk-through videos cover the Analog Board and SONY PSU. I also have a video on how to use the SEASONIC power supply as a replacement PSU, for those who don't have a SONY PSU or who want something more powerful. I don't yet have a motherboard recapping video because all my motherboards are already recapped. You should also open your keyboard to check if that needs recapping (they often do). About the only thing I've not recapped yet is my Micron Xceed Grayscale adapter, which uses electrolytic caps. (The stock SE/30 Yoke board doesn't, so you need not worry about that.)
  15. The WIKI still says V5.5 is "coming soon." I'd love to see a photo of yours!
  16. The SE/30 has a stock 16MHz 68030 CPU. Even 7.5.5 is a bit slow on the stock CPU. 7.6.1 isn't really slower than 7.5.5, but it has a longer boot time. OS 8.1 even with a 50MHz 030 accelerator is a bit sluggish due to all the eye-candy Apple added. An 68040 is nice for 8.1, but a lot of older software, especially System 6 apps, crash under the 040. A 50MHz 030 is really the best acceleration option for the SE/30, I think. But you also need a lot of RAM if you want to run 7.6.1 or 8.1. I would recommend at least 16MB. 32MB is ideal. 128MB will let you do anything you want, but 16MB SIMMs are not always that easy to come by. Currently, I have a 4.5GB IBM DGHS-04Z spinning platter hard drive inside an Apple external HD20SC enclosure, which I can switch between each SE/30 I use. I also have internal drives for those machines as well, but those are all less than 1GB in size. I've long been considering the purchase of a SCSI2SD but I've never got around to it. Anyway, I keep all partitions to 2GB or smaller on my 4.5GB HDD to ensure System 6 can see all the partitions. I have a 1GB boot partition on that same drive which contains all my operating systems, and System Picker allows me to switch between the operating systems. I tend to use System 7.1 more than the other operating systems because its fast and compatible with a lot of software. I need System 6 to use some older apps. And let's be honest, System 6 flies even on a stock SE/30. I love the speed. My System 7.5.5 folder is currently not hacked in case I need System 7.5 on an SE/30 with a stock ROM. If I want System 7.5.5 features on a non-stock ROM, I can use 7.6.1 because it's largely the same as 7.5.5. OS 8.1 is there mostly for fun. Seriously, if you need an OS that new you're probably best served with OS 9, but that won't run on 68k Macs. There are times when I want to run much older software -- games like MacAttack and the like. For that I would need a Mac Plus or older. And I just happened to have a couple 512k Macs, one with a GCC HyperDrive inside, both with the original 64k ROMs (which mean they use 400k floppy drives).
  17. Download: Wish I Were Yes, I have the best of all the compatible systems on the same 1GB HDD partition: System 6.0.8 System 7.1 (the best System 7 in terms of speed) System 7.5.5 (for software that won't run in 7.1 or below) System 7.6.1 OS 8.1 I have a IIsi and IIfx ROM which allows running of all those operating systems. But I like my ROM-inator II Mega better because it has an additional hack that allows my HD20 to work with the SE/30. (Yes, I have a real HD20 HDD drive.) But mostly I liked the HD20 compatibility because it allows me to run my FloppyEMU in HD20 mode, which in turn allows me to boot off a 212MB "*.dsk" I created that has System 6 and lots of software -- all from the floppy port. I could make an even bigger dsk if I wanted, up to 2GB in size with System 6. What I really wish is that there was a SCSI drive that was similar to the FloppyEMU -- something I could easily connect and disconnect EXTERNALLY to move software faster and easier than even the FloppyEMU (which is slow because it connects to the floppy port). Of course, the FloppyEMU is powered from the floppy port which is nice. And a similar SCSI drive (with SD card) connected externally would need its own separate power source. Even so, it would be nice to have. SCSI2SD is for internal installations, not external.
  18. It's been a long while since I booted into 7.6.1 and OS 8.1, but I tried it just now without problem using my ROMinator II MEGA. But I had already hacked the system files, so it wasn't surprising I was able to boot without problem. Interestingly, I have "Wish I Were" installed in my 7.6.1 System Folder and set to "IIsi," but I don't even have it loaded on 8.1 and 8.1 works fine. According to the ROM-inator II documentation, OS 8.1 should have Wish I Were set to a Quadra 700 for some reason. You can read that here: https://www.bigmessowires.com/mac-se30-with-upgraded-rom/ What does "Wish I Were" even do? It's obvious it's not needed in OS 8.1 as per my test just now working fine without it. But I'm curious if there are some situations that may require it. (Apple System Profiler in the Apple menu won't load and just beeps at me under OS8.1. Curious if that is a "Wish I Were" related problem or just a ROM incompatibility.) By the way, if you're wondering whether to run 7.5.5 or 7.6.1 (or even OS 8.1) with a non-stock ROM, check out this LowEndMac Article.
  19. When you had the ROMinator II installed and when you tried to boot System 7.5.5 (with hacked System file), what did you see on the internal CRT during boot time? Sad Mac? Gray screen with no content? Disk icon with flashing "?" inside?
  20. Right. In your earlier post you first mentioned your use of the ROMinator II and then you spoke about the need to add Mode32, which I assumed you meant you were still using the ROMinator, in which case you would NOT use Mode32. Of course you need Mode32 under the stock SE/30 ROM, although you would not need it for the IIsi, IIci or IIfx ROMs, which all work in the SE/30. As to the 7.5.5 hack, I've not hacked mine in a while, but if you already have 7.5.5 installed, I don't see why you need to install 7.5.1, then do the hack, then upgrade over that hack. I would think all you would need to do on an existing 7.5.5 install is do the ResEdit hack as described on the ROMinator web page.
  21. Neal, you are not supposed to use the Mode32 extension when you use the ROMinator. And as to getting system 7.5.5 or 7.6.1 or OS 8.1 to work with the ROMinator, you must use resident to hack the System file as per the instructions given on the ROMinator product web page.
  22. Not sure if my VGA 17" display supports "Sync on Green" but it doesn't seem to. I put my Color30HR card back into my SE/30, then switched on only 3 & 4 for VGA on my UnimacFly adapter, leaving 5 & 8 OFF because the adapter says to when using "Sync on Green." When I flip power on, I get the standard gray screen on my CRT but nothing appears on my VGA display. So that seems to show this display doesn't support Sync on Green. Not that it really matters anyway because I don't think either Xceed Card outputs "Sync on Green." So the question is, could the bad VRAM which causes the vertical line in some color modes on the internal CRT completely prevent communication with an external display? Again, I don't know what I'm looking for when testing signals on my MacroColor30HR card's external monitor output, so if anyone does know what I should look for and on what pins, please let me know. But even then, let's say I test and find I am not getting the signals I should. Again, could that be the result of the bad VRAM? Thanks.
  23. Question for those of you SE/30 owners who use a PDS video card with an external display. I have a Micron Xceed video card and grayscale setup. Grayscale works great on the internal CRT, but I've never used the DB-15 port also offered by the video card. I have a 15" Color VGA LCD that's about 10 years old. Would this adapter on Amazon be all that I would need? (Not sure how those DIP switches on the adapter are used in case like this though.) Note the horizontal scan rate mentioned in the Xceed manual page below of 31.5kHz, which seems rather odd (maybe common for Apple though?). Any thoughts would be appreciated. Thanks.
  24. I finally fixed the ROM-inator II Mega with a thicker paperclip as I describe in this post.
  25. @Dog Cow You are the man! I've not tested it with my FloppyEMU attached to my SE/30 yet, but your beautiful advice worked perfectly in miniVmac! An absolutely wonderful solution. A thousand thanks for your specific advice that solved this problem!