Jump to content

Search the Community

Showing results for tags 'capacitors'.

More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


  • Important Information
    • The 68kMLA Forum Rules
  • Community Connections
    • General 68kMLA News & Stuff
    • Conquests
    • Trading Post
  • Projects & Hosted Forums
    • RetroChallenge
    • 68kMLA Wiki
  • 68k Model Forums
    • Compact Mac
    • Mac II, Quadra & Centris
    • 68k LC & Performa
    • 68k PowerBook
  • PowerPC Model Forums
    • NuBus Power Mac, LC & Performa
    • PCI Power Mac & Performa
    • G3/G4/G5 Power Mac, iMac & eMac
    • PPC PowerBook & iBook
  • Everything Else…
    • Apple I, ][, /// & Lisa
    • Newton
    • Software
    • Hacks & Development
    • Peripherals


  • Community Calendar

Find results in...

Find results that contain...

Date Created

  • Start


Last Updated

  • Start


Filter by number of...


  • Start





Website URL












Found 27 results

  1. Ran into an issue where my power adapter for my Powerbook 540c was outputting 16v on one pin, but only 2.xv on the other pin so my 540c would no longer start up. Took the PA apart(it's epoxied together) and discovered 6 capacitors. 2x 330uf - 25v, 2x 100uf 200v, and 2x 100uf 25v. The part numbers can bee seen in the picture. While the capacitors didn't look bad, I knew they were 20 some years old and it was time to swap em out. Sure enough, as soon as I soldered in the new caps I got 16v back on both pins and my Powerbook 540c is happy again!
  2. Hello I am going to be reworking the logic board on an SE/30 and am looking for a list of capacitors for the board. The board I have has already gone through a repair by an unknown third party and I intend to remove all the caps he put in place. I would like to install the original electrolytic capacitors and other caps that the board hosted. I don't want to go with tantalum capacitors because of their very disruptive end of life characteristics, namely they can blow up. I would appreciate if someone in the know could provide me a list of caps and their respective locations. Kindest regards —Alex
  3. I thought I'd post this here to perhaps help some. I have a Classic II which worked OK, but with only a faint sound. So I thought I'd recap, but only those caps I guessed were involved in sound. Started with C11, C12, C14 and C15: no help Then C9: no help After I changed C4 (47uF), I finally got a loud bong. However, I lost the mouse pointer Thinking I must have shot C5 and C8 while hot-airing that area to desolder, I changed them too, and I recovered the mouse pointer So everything looked fine, except for a heavy random hissing/whistling of the speaker. I then realized that C11 had not been soldered properly. After this was fixed, everything works OK. Great feeling So next time someone is having a sound issue with a Classic II, I'd recommend to start with C4.
  4. I finally finished my video on recapping the SONY CR-44 PSU, which can be used in the SE and SE/30. The video is long but informative. A Mouser Cart is linked in the text description under the video (you'll have to watch it on YouTube to see that), for those of you wanting to easily purchase all the electrolytic capacitors required. You also find a link in that description to my SEASONIC PSU replacement video, for those of you who haven't seen that one either. There's still reason to recap the SONY PSU though -- it's fanless and dead silent when operating. If you have only 1 PDS card and no major upgrades, the SONY PSU, once recapped, is more than adequate. Enjoy.
  5. kahlil88

    Mac SE/30 no video after re-cap

    Finally got around to re-capping my Mac SE/30 board, after swapping the CRT from an unhappy Mac Plus and confirming signs of life. Screen came on and I could even boot off my Floppy Emu, though sadly the ADB ports appear to be dead. I knew it could use a re-cap after 30 years (at least 15 of which it was used as a door stop at my old high school). Re-cap went smoothly, and afterwards I cleaned the board with soap and a toothbrush, pressure washed with hot water, then shook and sat to dry overnight. Powered on the next day and I get a chime but no video. I decided to have a go at re-flowing UE8, UF8 and the other chips in that row, along with all the caps I had replaced (a few weren't as flat as they could be). Powered on and not even a chime. Went back for a second pass and ended up breaking a leg off UF8. The speaker chimes again but then blip-blips indefinitely, almost like it's stuck in a reboot loop but doesn't fully chime after the first one.
  6. curtiscoffee

    Macintosh SE Not Working

    Hi, This is my first post on these forums. I felt this would be the best place to come to ask how to get my Macintosh SE working again. So I managed to get my hands on this Macintosh SE. It came with the original manuals, mouse, keyboard, and even a carry bag! I paid around $5 New Zealand dollars for it. Yes I can't believe it either. So when I got it home, I plugged it in and it turned on, and it worked! I think that the disk drive is dead, because it just had the disk logo with a question mark and ejected the yellow protector disk. I left it on for a few hours. I then noticed a burning smell and smoke came out of the back of it. I opened it and being very careful i turned it on and i noticed that the flyback transformer was arcing and the monitor wasn't turning on, But I did get the start up sound and the fan was running. At first I thought a cap had popped on the analog board, but after inspecting it they all look perfectly fine. Also checking the main board it looks perfectly fine and the battery hasn't leaked. Has anyone else had this problem before? Any help would be greatly appreciated.
  7. Recapping a Macintosh IIsi Power Supply Related reference (cheat sheet): http://recapamac.com.au/macintosh-iisi-power-supply/ or on archive.org, http://web.archive.org/web/20191125110228/http://recapamac.com.au/macintosh-iisi-power-supply/
  8. mac1nt0s

    Analog Board Recaping Advice

    Hello! I've decided to recap the analog boards in my Macintosh SE and SE/30 and now I need to buy the caps and I'm wondering a few things: - which company should I buy the caps from (there's quite a lot of different companies and I don't really know which ones to buy)? - should the max operating temperature be 105 C or is 85 C enough, considering that the SE and the SE/30 have a fan? - is it okay to buy the caps from AliExperss (I know that Mouser is generally the best for capacitor purchases, but the shipping is quite expensive, because I'm located in a smaller country and I really don't want to pay that much for shipping)? Thank you for taking your time and helping me out!
  9. So this is not about the retrobrite that the 8-bit guy completed, that turned out very nice. Instead it is about this really bad video he did, sorry I know some of you may like him but this video was wrong in so many ways that I had to warn potential viewers. I couldn't comment on youtube because they were not available for this video. Do not twist off caps from any logic board, it's not in the manual as it were for a reason … you run the risk of ripping of the pads that capacitors are soldered to. Once a pad is removed through the force of twisting off a cap, a time consuming repair is definitely at hand, even if they don't tear off the board they can come loose causing continuity problems later on. Please watch some other videos on how to desolder. No manual will ever tell you to twist off a capacitor but you will find desoldering procedures. This is the legendary Mark Siegel from PACE. I don't expect folks to purchase all this gear to remove a few caps but this man is a legend for a reason. You can learn a lot from him and the other PACE video below. These are really interesting videos in my view. You will learn so much! There are excellent videos on the topic of soldering, it's actually an amazing thing (tin and lead). I hope you find these interesting. Washing logic boards in a dishwasher, this is medieval (sorry what term should I use?), the water is not the proper kind, it can leave minerals and other residue behind that in the long term has a negative impact. He could have cleaned his board with isopropyl alcohol and a for for purpose anti-static brush or taken the time to clean up manually with a cotton swab. -- The lesson videos on soldering by PACE will present cleaning methods throughout. No ESD protection? Without grounding the board and yourself the risk of electrostatic discharge is completely possible and any damage is practically undetectable by our senses. The damage this discharge can cause is microscopic and can result in latent issues that manifest into crashes, system freezes etc. I hope this will equip you to perform any rework on your Mac or other electronics with safety to the board while ensuring a good solder job and good clean up.
  10. Hi folks, this is my first post here and I’m looking for some help diagnosing yet another video issue with a Mac SE/30 - hoping that someone could point me in the right direction. Usual story, dug the Mac out of storage to find it didn’t boot, display full of stripes and noise. Removed the caps, cleaned out the electrolyte, dirt and oxide, replaced caps. The board looks great, no visible broken traces and squeaky clean. Connected to power, the Mac chimes, POSTs and boots all the way to the Finder normally, the mouse and floppy work. The issue is only the left quarter of the screen is being drawn, as if divided into four columns, leaving horizontal strips across the rest. In the Finder I can make out the trash and menubar but being continually overwritten in the same quarter screen. It’s as if only 25% the VRAM is being written, but the whole memory is being read back out to the video circuit. With the RAM and ROM SIMMs out the Mac shows a stable full screen stripe pattern. Swapping out both RAM/ROM with a known good set yields the same results. I’d appreciate it if anyone could offer any advice on what could be happening. Before I buzz out the entire board or start replacing chips I’d like an idea of what’s going on.
  11. 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)
  12. SE30_Neal

    Is this Circuit board normal

    Hi Guys, i brought a used a/b analogue board/sony psu combo as a temporary replacement for my se/30’s whilst i recap and clear up my original items. The replacement board is from an SE which I believe is identical? Basically I’ve been experiencing some minor shimmers/flickering especially when cold (3-4 months now) so i thought it was about time to re-cap both my analogue board and psu as the motherboard had already been recapped some time ago, including a new battery. Question is psu board looks a little unusual, at first i though it was spilt liquid of leaking capacitors yet on inspection the caps all look great; no swelling, no residue, no corroded tracers. I used a q-tip to clean the edge and nothing came off. Its almost like varnish. Is this normal on the sony PSU? neal
  13. It took me a while but I finally got my SE & SE/30 Analog Board recapping video published to YouTube today. Safari users, note that you'll need Chrome or FireFox to watch it in 4K. Don't forget to watch it on YouTube so you can check out the links I put in the text description (click SHOW MORE to see all of it), including the Mouser Cart that includes all the capacitors you will need. Enjoy.
  14. I made a new walkthrough video about replacing all the electrolytic capacitors on the MicroMac DiiMO 50MHz 68030 accelerator for the SE/30. I explain my choice of Niobium Oxide capacitors over tantalum, show the replacement, then boot and run benchmarks. The SE/30 shown has a recapped motherboard, recapped analog board, and SEASONIC PSU. The video is 4K but if you're a Mac user who loves Safari, you'll need Chrome to view it in 1440p or 4K. Also, it was sadly during the making of this video that my Epic Blunder occurred. My humble thanks to all of you who are so kindly trying to help me in that thread. I make videos for the enjoyment of it and as a way to give back to the community. I currently don't allow ADs on my videos nor do I have a Patreon account, which is why I've never earned any monetary compensation at all from my videos. (The down side of that is Google doesn't suggest my videos as well as videos with ADs enabled.) I make videos that I really wish someone else had made for me. Even though what you see in my videos isn't necessarily groundbreaking or unique (some of you are far beyond me in terms of troubleshooting knowledge, repairs and mods, for example), I simply am transforming into an easy-to-digest video what otherwise has been exclusively found in "text form" in forums like this. For the new generation of younger people who don't prefer to read, videos are becoming increasingly important. (Even so, I still get Millennials complain my videos are too long, so we can't please everyone. I prefer to be thorough rather than worry about the clock though.) My next video endeavor will be to show the recapping of an SE/30 analog board, and then I will have yet another video showing the recapping of the SONY PSU. Anyway, I hope this information is useful not only for you DiiMO owners but also for those of you who need to recap 5V voltage rails, as the Niobium Oxide caps I chose work perfectly for that, assuming you need 22uF. They come in other sizes though so give them due consideration in your recapping jobs.
  15. Hi all, Picked up a Mac Portable 5120 (non-backlit) last week; before powering it up, I removed the logic board, removed the caps from it - all of them, except the tantalum cap on the hybrid board - cleaned the board, replaced the caps, and got a new black 6v 4.5ah brick battery. Putting it all back together, it won't boot off of the battery alone - the screen flickers, and it either hangs on a flickering mouse-pointer screen, or flips over to the chimes of death. With the original Macintosh Portable power adapter and new battery connected, it will boot 90% of the time. When it falls, it simply does nothing. Based on previous threads here, I'm suspecting the hybrid board. I did find one bad trace on there, which I have bridged, but no change. Wondering if anyone here has any ideas to help narrow down the next vector of attack. I want to test continuity on all of the hybrid board traces, but I lose some of them beneath ICs.
  16. I have a functional Xceed grayscale adapter that looks exactly like joethezombie's photo. There are 4 electrolytic radial capacitors that are old enough to warrant replacing, especially so since they are only temperature rated up to 85°C: C4: 10uF, 16V C5: 47uF, 10V C8: 100uF, 16V C9: 100uF, 63V There are numerous 10,000-hour 105°C rated replacements available on Mouser. Have any of you grayscale adapter owners performed a recap on your adapter? And more specifically, do any of you understand the function of the adapter well enough to know if replacement caps with significantly lower ESR (than the stock caps) would actually create problems? Thanks.
  17. sixsevenco

    Need guidance on Classic II repair

    Hi Everyone, My Classic II arrived! Cosmetically, it's beautiful, but it definitely needs recapping. The electrolyte fluid leak is very obvious. I don't see any corrosion, so that's good. Anyway, I have tried to do my homework, and figure as much of this out as possible. But I've hit a point where I am stuck, and I could use some help. My board has 13 capacitors. Looking at the reference for my board at maccaps.com, I see that I need to buy the following replacements capacitors: 8 - 10µf - 16V - SMT 3 - 47µf - 16V - SMT 2 - 1µf - 50V -SMT First Question: For the first capacitor (10µf - 16V - SMT), there are 887 options on Digikey that meet these specs. How do I narrow this down to a specific capacitor to buy? Do I need to worry about tolerance? Dimensions? Or should I just go with the lowest price? Second Question: Should I recap the power supply while I'm at it? The caps on the power supply seems to be through hole, so that will likely be an easy task... Third Question: I've read that there is a bleeder that should discharge the CRT. Any chance that isn't working as intended? I've never worked with CRTs before, so I'm a little intimidated. Fourth Questions: Are there any guides on how to service/lubricate the floppy drive? I haven't found any. (admittedly, I haven't looked that hard.) Thanks 67
  18. Hi All, I got a chance to inspect each of the 3 SE/30 motherboards I have for 2 systems. It has been a few years since I have looked at these and I am pretty certain I sent 2 of these away for a recap job however I am not an capacitor expert and could use help identifying the work done on each. Apology in advance for the quality of the photos. This is the board that came in my original SE/30: I thought I had this one worked however those appear to be the original caps. Is that correct? This is a socketed board I got off of eBay that looks like work has been done to it: This is the board that came with a system that had a Daystar 030 Accelerator attached to the board. The original non-socketed CPU was removed for the Daystar to plug into, however, the photo has the stock CPU inserted... This one too looks like it has had work done however the caps are different than the stock socketed board... THx!
  19. Hello people! I recently acquired a Mac Plus while doing a clean out of my grandfather's old factory. The keyboard and mouse were FUBAR, as they had been left under an old can of paint which leaked all over them. He said that there was also a hard drive somewhere, but we couldn't find it. I scrubbed as much old paint of this Mac as I could, and besides from a rather even coat of yellowing, it seems to be in pretty good nick. I took it home and plugged it in, and it made the start up bong and the floppy drive made noises, but the screen never fired up. I cracked open the case and besides some dust, everything seemed to be in relatively good shape. No caps were leaking, and nothing looked corroded. I also discovered that this Mac had 4Mb of RAM. Nice! I came to the realisation that this Mac had deeper problems. I noticed when I found the Mac, that it had LOTS of screen burning, which indicated to me that the CRT as a whole could have just bit the dust, or that the flyback transformer was completely screwed. Further poking around inside the machine also revealed that the CRT power connector looked like it was burned or melted. I thought while I had it open, I'd perform the cap change just in case, for longevity if I ever got this thing working. I couldn't find all the correct caps, so I used some higher volt ones, and there was one blue non-polar one that I didn't change at all. Upon firing this up after the change, it worked! I have no idea why the cap change fixed it, non of the caps seemed damaged in the slightest, I verified this when I removed them. No residue or anything! So now I have a semi working Mac, but I have 2 issues which I'm unsure of how to fix. The computer makes a REALLY REALLY high pitched squealing noise. I think this may be the flyback transformer, but I'm not sure. UPDATE: When I fired up the machine to take the photos in this post, the noise was gone! I'm unsure if it will come back, has anyone else had this problem? It's also VERY hard to insert floppies into the drive. The seem to be stuck on something, I'm not sure what though (I've made sure it's aligned correctly). Also, sometimes when I put them in, the jitter around in my hand like crazy until whatever mechanism in there stops, and I can finally insert the disk! And on top of that, the auto eject doesn't seem to be working, but I'm not that familiar with macs that boot directly from disk, as my other mac (a mac classic) is currently not working AND it has a hard drive. I also have no boot disk to test this machine further. Let me know what you guys think!
  20. SlateBlue

    SE/30 Woes

    I recapped my SE/30, and the repair failed to fix it. Prior to recap, the Mac had horizontal bars from top to bottom and no chime. The attached photo shows the screen after recap was completed, and still no chime. I checked to make sure RAM was installed properly. Also, if I remove the RAM, the horizontal bar pattern returns. Any help would be greatly appreciated. I apologize if the pic is oriented incorrectly. The uploader does this automatically and I'm not sure how to rotate the photo.
  21. I picked up a Macintosh Classic at an electronic waste roundup the other week. Despite the case being badly discoloured and giving a RAM-related Sad Mac on boot, I could tell that the Quantum HD was still spinning and the display is really sharp. The machine has its problems, and I'm wondering if it's worth refurbing. Your advice/opinions on the following are welcomed: Capacitors — I recapped the logic board and replaced the PRAM battery. The logic board caps had all leaked, and cleaning up the mess was not fun. The battery, though dead, hadn't leaked. The Fishy Smell — The analogue board looks clean, and the display is steady and sharp. The machine still smells pretty rancid when it warms up, though. I thought I'd cleaned all of the capacitor goo off the logic board (even the stuff crusted under the SCSI controller), but maybe the smell is some left over. Floppy Drive — the SuperDrive doesn't recognize formatted disks. If you let it format one, it clicks through all 80 tracks formatting, then verifies, then reverifies, then spits the disk out with an error. I haven't cleaned the heads or done any of the lubrication tricks yet. RAM — the two 30 pin SIMMs on the daughtercard don't seem to be recognized, so unless I set the jumper to “SIMM not present”, I get the Sad Mac. I tried alternative SIMMs from a local salvage place, but got mostly the same errors. As is, I'm stuck with 2 MB until I work out what's up. Do these daughtercards ever fail? Case — cosmetically horrid, with yellow discoloration on the main case and keyboard. So display, hard drive (completely with slightly messed-up 7.1 installation), keyboard and mouse are fine. I realise that an 8 MHz 68000 ain't all that, so I'm wondering if further work on this is worth the effort.
  22. SlateBlue

    Macintosh Classic AB Recap

    Hi everyone. I thought I'd take the time to create a post about my recapping adventure, and maybe take the opportunity to ask a few questions. If the is dry reading for you, I apologize. I'm not known for being a good storyteller. So, for starters - A several months ago, I acquired a Macintosh SE and a Macintosh Classic. The SE appeared to work just fine (still has original caps on board), and was in overall good condition with minimal yellowing. The Classic would boot fine, but had no sound, and the case had significant yellowing. I removed the logic board from the Classic to find that all the SMD caps were leaking. I set the SE aside and went to work on the Classic. After a botched repair attempt (a couple of lifted pads), I sent the board to Novi, Michigan for a professional recap job. The recap fixed the sound issue, but I still had yet to tackle the cosmetic issues of the machine. Pressed for time on other projects, I set the Mac Classic aside to be worked on at a later date. Last week, I finally took the time to completely disassemble the Mac Classic so I could retrobright the front bezel and rear case. I also took the time to blow compressed air over the AB to remove years of dust. Upon reassembling the computer and powering it on, it seemed the hard drive would quite spin up. It would try, and with each attempt the screen would flicker. Thinking I had a bad hard drive (it worked weeks prior), I swapped a known good working one to find that the issue persisted. I then realized I likely was dealing with a voltage issue. I measured both +5v and +12v at the external floppy port and realized the voltage readings were low ~ around +4.8 and +11.65 respectively. So, I adjusted PP1 until both voltages were in an acceptable range ~ +5.05 and +11.99. I suspected that the compressed air had somehow turned the potentiometer and decreased the voltage. Yesterday, after cleaning the floppy drive, I noticed the screen would appear to shake/wave slightly as the disk drive was working. Thinking again that I had a voltage issue, I measured at the external floppy port again. The voltages were ~ +5.15 and +11.77. At this point, I realized adjusting PP1 wouldn't fix the issue. Too little voltage is worse than too much, right? So, I removed the AB and desoldered the caps from the bottom left/center of the board (yellow box in attached photo) to find them all leaking. I guess it's time to recap the AB now. My questions: I know that I must match the capacitance and voltage ratings of the original caps. Must I also match the physical size? Can someone explain whether one should choose General Purpose or Low Impedance caps and why? I searched the Interwebs and could not find a capacitor list for a Macintosh Classic Analog Board. Can I get away with leaving the smaller (physical size) caps alone? None appear to be leaking. Thanks!
  23. I've bought a Macintosh Classic computer recently, it was in a very nice condition with original keyboard and mouse, but with an issue of a chessboard-like pattern displayed on the screen all the time. At first I thought that it might be caused by capacitors leak on the logic board, but after I've cleaned the logic board in a dishwasher and than with pure alcohol, nothing happened — the pattern on display was the same. So I decided that caps are dead and need to be replaced. I've replaced all the capacitors on the logic board, but again with no result. After that I've found the information about this issue might been caused by broken capacitors on the analog board, so I've replaced a group of caps mentioned here (http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/1990/10/15_Macintosh_Classic_Analog_Board.html) total 8 caps, although they aren't all the same as in the guide, cause I have a later model (1992) I suppose. Still no result, the pattern on the screen is absolutely the same. What else could I try? Any help or ideas are much appreciated!
  24. I've had a box of 20 or so IIcx logic boards in the attic for a decade or more. I got the batteries out of them early on, so I never had a battery explosions, but I've been contemplating the damage leaking capacitors will do over time, and thinking I really need to get the box down and pull all the caps. So, I'm in the process of doing that now. It's a slowish process. I don't have time to actually test and "repair" each board, but I want to halt any damage. After I pull the caps, I'll thoroughly clean the boards. Now, here's the question: Is there any particularly vulnerable spot on the IIcx where capacitor goo collects and causes damage? In other words, anywhere I should apply extra attention while applying the solvents and cleaning? I would hate to remove the caps, clean the boards, and leave corrosive goo hiding under some chips eating away traces. The 74 series chips around the battery holder and the Right Sound Chip look like likely candidates. At least, on most of these boards, their pins have a fair bit of corrosion. I think these boards were originally part of Shreve Systems collection of old boards. One of them had a note on it dated '96 saying it wouldn't work. I bet the caps had failed back in '96. My IIci needed new caps by '97. Many of these boards have no ROM chips. Does the IIcx typically have them soldered down? If so, then why in the world did someone remove the ROM chips from so many of these boards? It's not like you can put them on a SIMM. The logic board ROMs are too large. Then there's a few boards on which the traces have pulled up like a bunch of little hairs. But I guess the custom chips will be useful for other repairs.. Do I remember reading somewhere that the sound chips are actually a D to A converter available under a regular non-Apple part number? I got one of the Quadra 840AV boards down while I was at it. This one had a note I made from 2007 saying it was working. I hope it still does. There's a lot of visible leakage around the caps now. I need to find the other one, which is actually in an 840AV case and remove its caps too. Geeze. I thought I was doing good to remove the batteries. I could spend a lot time removing all the SM electrolytic caps from logic boards in the attic.
  25. I recently acquired a working, but neglected Quadra 840AV. It came with 3 hard drives installed, an original CD-ROM drive, and with a 64 MB of RAM. It clearly needed a total recap of a motherboard and a good cleanup, which I did. Then I tested the machine, and I found out that a CD-ROM drive wasn't detected, even that it was connected properly. I figured out that it must be the drive that failed. Then I cracked open the Sony CDU561-25 drive, and to my surprise, I found capacitors that have leaked and corroded the PCB. The damage was quite bad, but fixable. There was a group that leaked, and they were three 16V 47uF and two 16V 10uF silver electrolytic SMDs. On the left side of the PCB, there were four 6.3V 100uF that looked okay, but when I changed them, they were certainly on their way to fail (fishy smell). So when I replaced them all with tantalums, the CD-ROM drive now works flawlessly, and I know that they won't leak ever again. Also, I was impressed with the build quality of this particular drive, it is massive and it has a voice coil laser mechanism, which just screams high quality all around. So, next time your CD-ROM drive fails, check the caps inside the unit. Also, if you have a Sony CDU561-25 or similar, it will be the smart idea to change the caps just to be sure, even if they are not leaking. Sometimes the CD-ROM unit will cost alone more than a complete computer, so it is worth it.