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Alex

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  1. I am not an expert myself but I think you could agree that there is something to be said about relying on the experts who really specialize in these areas. I believe the problem with tap water has to do with those impurities which might not wash off the board and cause problems down the road. It should also be pointed out that tap water varies from location to location for numerous reasons. I believe the overarching issue with tap water or similar has to with with pH or alkaline levels which can be problematic, perhaps not immediately but intermittent issues may arise down the road. Or perhaps this is like opening up a platter drive in a non-clean room environment. I am not sure if these are acceptable analogies but this is all I can come up with, maybe these similarities can help you find better analogs. I would tend to put this in the same ballpark as practicing ESD safety when handling PCBs to avoid static discharge. I posted a video on this way at the top. But @Crutch I do apologize for not being able to give you a solid answer on this. I posted some links, at least one tackles the question but it's one of those things. I think if you simply use isopropyl alcohol and a brush you will be fine, the results can be extraordinary. Alternatively, if you use water I would immediately (while the PCB is still wet), dip it in a bath of isopropyl alcohol as it will be pretty good at repelling the water away from the board. I hope this helps. @LaPorta I don't know the answer to that, I don't use one myself but perhaps this forum post on another forum might be useful? https://www.eevblog.com/forum/reviews/pcb-ultrasonic-cleaner-recommentation/. If you plan to buy one just for a single board it could be an expensive proposition. Maybe a used device could serve your purpose and save you some money and the environment in the process.
  2. Your question was raised here but I didn't get a chance to read it all as other things are on the go. http://www.circuitnet.com/experts/70402.html Here is a caption from one answer given: If you search for "pcb cleaning" + "tap water" in your search engine you will find resistance to tap water due to contaminants that are left behind. I've done it once on a PCB for a dead Sony CRT but that was the only time. I stuck it in the dishwasher but I would never do this to a Mac logic board that I care about. I don't have an ultra sonic cleaner so I can only use isopropyl alcohol and an ESD safe soft brush. The problem with this is that I can't get under components that's why an ultrasonic cleaner is preferred but I can only make due with what I have. An ESD brush and isopropyl alcohol is not expensive at all.
  3. Links on cleaning PCBs … just a list of references. You can enter "pcb cleaning" in your fav search engine to find more articles. Tap water is not a good option because it leaves residues, DI water or deionized water can be an alternative. Some of the links are technical while others below are more general and useful. I think most of us have limited tools for cleaning but a brush and isopropyl alcohol is a good choice. Both are not expensive. Hope this just adds to the discussion and knowledge. https://www.wellpcb.com/special/dirty-pcb.html https://www.embeddedarm.com/blog/deionized-water-the-gold-standard-for-electronics-cleaning/ To sum up, tap water is a known bad soluble when cleaning boards in the electronic industry. DI water has many benefits over tap water for the longevity of the boards the customer receives. The pure water washing process will leave boards clean and free of contamination and is far superior to using dirty tap water that might possibly cause defects in the field. https://www.ifixit.com/Wiki/Electronics_Water_Damage https://gesrepair.com/clean-circuit-board/ https://www.kolb-ct.com/cleaning-tasks/product-cleaning/pcb-assemblies-cleaning/ https://www.kemet.co.uk/blog/cleaning/pcb-cleaning https://www.digikey.com/en/maker/blogs/cleaning-pcbs https://www.digikey.com/en/maker/blogs/cleaning-pcbs
  4. I appreciate everyone's comments, I should make one correction. It was really late when I wrote this so I hope you can all forgive me but he did not twist the caps, he rocked them back and forth, which might be considered more desirable but I still prefer using heat to remove them. I should make that correction for what it's worth. Despite this, I much prefer folks be given the advice to use heat to melt the solder as the safest method of cap removal. If your pad comes off even when using heat, a serious amount of damage to the board can simply be expected. The epoxy used to adhere pads can withstand heat of up to 800 degrees celsius or more which is way beyond the melting point of any solder so using heat should not rip off any pad unless, again, the corrosion caused by a capacitor's innards have been exposed for dangerously long periods, in extension this could also apply to the innards of a battery leak. Granted I do not know if either type of leaked material puts at risk the epoxy holding down the pad this would depend on the severity and exposure time these chemistries play on the board itself. In any event, my original post was to simply put some perspective on his procedure which is not the advice I would have given for reworking a board, generally it is unfortunate that many youtube videos are providing out of spec instructions and I appreciate that some of you have cut off caps or twisted, rocked them without an issue. I am not saying it is luck that saved the board each time maybe you have a very good sense. I see the reason why this is the case, it's much easier and quicker to rock or twist off caps and just have cleanup as a post process but there are risks that are innate to applying physical force. As long as folks know those risks we are all free to use our own methods so I pasted those videos that provide best practice but of course doing things procedurally requires more time but yields as a little risk as possible. I should add that the PACE lessons have so much good advice that they stand on their own as a reference for so many types of soldering methods and good practice measures. Thanks again for all your input, just take care of your boards and inspect your machine's from time to time, age can be their downfall. Kind regards —Alex
  5. 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.
  6. Hi Cory Tabbed folders, as in the example screenshot, it shows three folders all attached to the base of the desktop, one of which has its contents in view. Perhaps I wasn't clear; if the 9600 graphics accelerator extension is not loaded on startup, the tabbed folders continue to work as expected but when clicked, to reveal their contents, the animation of the tabbed folder sliding up to reveal its contents suffers (jittery animation without extension loaded). The only real issue, even with the extension loaded, is a slow redraw (not very slow, just noticeable by today's standards, I might be spoiled with current Mac OS). The redraw concerns overlapping windows. So if click on a Finder which is behind another window it will force the now visible portion of the window to redraw itself and it's just a tad slower but I think that after testing it might be normal. I just came back from vacation 2 days ago so I will try to swap the card to another slot as recommended by @604ev, I think he is on to something interesting when it comes to arranging cards in the 9600 to accommodate the two controllers on the main logic board that handle PCI, I think his recommendation helps to balance PCI I/O load more evenly. I am absolutely going to do this and report back. Overall, I accept that this is a very old Mac and I think I am mostly dealing with being too optimistic on expectations when it comes to 2D performance on this Mac and video card. Thanks —Alex
  7. After having sent you a message, I can now see that you've been dealing with this for a while now. I wasn't aware of the activity log beforehand.

    Best

    —Alex

     

    image.png.41aa017649a04f3b25dbc50bf5941789.png

  8. Hi, In terms of the IIcx and IIsi that is correct, they sprayed the inside of the plastics instead of adding a proper EMI shield or faraday case as the iMac G4 uses. The White iMacs use a different kind of shield as well, it is an almost aluminum foil type of material so it varies from machine to machine but all in all I believe these are to prevent radio interference and is typically desirable for electronics and enforced through regulation by the FCC or other bodies in Europe and so on as governed by law. I believe the idea is to prevent the computer from emitting radio frequencies not the other way around. Electronics emit radio frequencies and if all electronics weren't housed inside a shell that prevent the emission there would be a lot of radio signals about and that would cause a lot of problems, especially for highly sensitive instruments such as hospital equipment, this is one of the reasons we are instructed to turn off our electronic devices on take off and landing on an airplane. Your IIfx should operate as expected even without those EMI shields unless they act as ground somewhere but due to their fragility I would doubt that. I am not an engineer to say this with any confidence but I would imagine the logic board is grounded to the power supply which in turn is grounded to the wall outlet. Was the IIfx shielding originally shiny in finish? For images of the original state of the EMI shielding please open: https://www.oldcomputr.com/apple-macintosh-iifx-1990/ By the way, some other machines that share the same type of shiny shielding are the 7x00 series Mac all the way up to the Power Mac G3 desktop, the latter I don't own but they all have the EMI shield under the logic board. Other Macs share this material in some cases just around the I/O ports and under logic boards, like the Power Macintosh 8600/9600 towers. I don't know why exactly they are 'tinned' for lack of a better term, it might be to simply prevent corrosion such as rust from developing on an otherwise flimsy piece of metal. It is possible that the proper spray paint contributed to staying with FCC rules on EMI shielding. I couldn't find out if a primer should be applied beforehand. I would contact one of the manufactures first just don't expect them to know what a Macintosh IIfx is, instead send a photo of the part instead, describing that it's for computer shielding. What I would do in your shoes: Personally, if I owned a IIfx (my first Mac was a Iix by the way) and I had already gone as far as you have I would be investing in a can of spray paint that is meant to not only protect the shielding but give it the qualities required to behave as intended, in this aspect, to prevent EMI emission - I could be wrong it might actually prevent emission and absorption of unwanted radio signal interference. To answer your other question, I believe the shielding would put the machine within specifications for hosting a display in top or around the IIfx. After going through the take-apart process it should be clear that this machine was well shielded, especially because it had so much potential for I/O in around and outside the box. If you think about it, almost every component in a computer, down to ADB, SCSI and other cabling is all heavily shielded. I would go the extra mile and find an appropriate spray to finish the job just right, that's how I would go forward. Maybe my philosophical bend on restoration can at times be overwhelming even to me because I know that it takes time to do and a project can take days for countless reasons, waiting for parts, waiting for paint or glue to cure, other interruptions or gaps of knowledge etc but it is rewarding to see a machine that once looked pitiful return to its' full or near full glory. I hope this helps you and encourages you. The IIfx seems to be a rarer find these days so even if it seems like a lot of work, it's worth preserving. This was the top of the line machine way back so not many were manufactured — they weren't cheap! Some manufacturer's and a description: Starts with a great description of EMI/RFI shielding. https://www.vacuum-metalizing.com/industrial-services/rfi-shielding-paint-coatings/ Appears to be a product for the IIsi, cx range as they enjoy a spray coating on the plastic. https://hollandshielding.com/Electrically-conductive-nickel-coating https://conformalcoatings.com/materials/rfi-emi-shielding/ Mentioned previously https://muellercorp.com/the-benefits-of-rfi-emi-spray-coating-for-components/ https://www.mgchemicals.com/products/emi-and-rfi-shielding/ I recommend a google image search for "RFI EMI Aerosol" or "RFI EMI Aerosol high gloss" (without the quotes) and you should land on a product. The package you want should be an aerosol, if you search for can you might need a brush and that might yield an uneven finish. Even finishes will require spraying. As a side note, the Quadra 950 actually has a gold colored coating on the inside of the plastic case. I came across a product for that. I typically start with google image searches and work my way backwards. Cheers! —Alex
  9. Alex

    Color Classic with weird behavior

    I am truly delighted that a few of you are impressed by the post. The most important thing I want to leave with any one who reads this is: 1) I once had to start from scratch too! There is a first time for anything, be optimistic! 2) Do not be afraid of the process, in fact you will relish in the rewards of doing this yourself. 3) Do not be afraid. (yes I said it twice) Best of all, the tools required are not expensive at all. I wish you all the best, keep us posted on the repair and please, if you are stuck or not sure what to do, please ask any questions, there are a lot smarter people than I here. When you are done, relish in the amazing Color Classic that you own, it's a neat machine, I own a Colour Classic, notice the "u". http://web.archive.org/web/20030623011714/http://kanchan.hn.org:80/ Keep smiling —Alex
  10. If you do some research, removing rust and applying a fresh coat of RFI EMI Spray Coating spray paint (not any kind of paint) the result will look like new and the faraday cage will behave as expected, blocking EMI/RFI signals from the machine's internals.
  11. If I am not mistaken that is the EMI / RFI (electro magnetic interference / radio frequency interference) shield, here is the theory. You will probably need a special kind of spray paint for it. Can anyone verify my claim. I think it will need to be nickel plated or tinned after the rust is removed. Here is the faraday cage (silver in color) for an iMac G4, just an example (ignore the yellow arrow, it's from the take apart manual) I am leaving other links for consideration. http://eab.abime.net/showthread.php?t=74944 I don't endorse nor am I affiliated with these guys but the text is worth reading. https://muellercorp.com/the-benefits-of-rfi-emi-spray-coating-for-components/ You can google or google image: "paint EMI shield"
  12. clean it with vinegar, get a big enough tray, add vinegar and let it sit 24 hours or so.
  13. Alex

    Color Classic with weird behavior

    Ahh and you'll need to know what parts are needed to replace the old caps. Replace them all. http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/1993/2/10_Macintosh_Color_Classic.html
  14. Alex

    Color Classic with weird behavior

    removing caps is very easy. The only thing you need to know is to never ever twist them off, ever. What you need to remove the caps: You will need flux You will need a soldering iron (400 degrees Celsius is what I see mine to for this operation) You will need solder Needle nose pliers to grip the cap. (watch the videos, they are very helpful if you've never done this, such good advice there) Post removal you need (cleanup): Cotton swabs Isopropyl alcohol flux solder wick (copper braid) I also strongly encourage the following: An antistatic mat (blue in image) connect the antistatic mat to ground point on your outlet ground yourself to the mat with an antistatic wrist strap (yellow line represent that wrist strap line to the ground point on the mat) Open a window or otherwise for ventilation, the fumes from the flux can be slightly annoying (maybe an irritant for some, not sure) Grounding the logic board will protect it from static discharge Note: There is a time when we all are afraid of doing this because we believe we will damage our computers, trust me, there is nothing to fear. Believe in yourself, be analytical (you know just analyze what you are doing) and be patient. So here is what I do: 1) I apply a generous amount of flux to both side of the cap. Notice that aluminum electrolytic caps have flat contacts (+ and -). Twisting off the cap will very likely rip the pads off the logic board that they are soldered to. That's why they are NOT to be twisted off. Heat is what sets them free. 2) Using the hot soldering iron melt a generous amount of solder to the locations where the caps "feet" are (marked in yellow) Note: The flux helps spread and keep the heat on the solder so that it remains melted slightly longer than normal. This will yield a very dirty looking region and if this is your first time you may believe you are damaging things - you aren't, all of it will be cleaned up later. 3) Now once the solder and flux are to the left and right sides of the cap, use one hand to grip the cap itself but don't apply any force just hold the cap with the pliers. 4) Using your other hand, hold the soldering iron and alternate back and forth, from the positive side to the negative side of the cap, just back and forth, applying lots of heat, keep going, no fear, the cap will be trashed so don't worry about it, apply heat to where those positive and negative contacts are. Eventually things will heat up and you may need to add more flux and solder, it depends but don't give up. Eventually there will be enough heat around the cap that you can begin to very carefully rock the capacitor until it begins to come loose. Remember it is the logic board pads that you are being most concerned about so that they do not come off the board. The cap is trash. That's all there is to it. Here is an alternate method using a hot air gun and the post clean up: Trust me, it is not difficult. The cap maybe stubborn to come off, just add more flux and solder and keep applying that heat and gently rock the cap left and right as you alternate heat to the cap's anode and cathode (+/-) with the solder iron. This video show the removal I proposed above but for some reason he prefers to use his fingers to grip the cap but you can burn yourself accidentally (not fun): Now this is what has to be dealt with after a capacitor is twisted off the board: This is an amazing video by the way. I just discovered this video and it is an absolute gem of a video, absolutely excellent. Do watch this please. Recapping Tutorial - how to replace old, leaky surface mount electrolytic capacitors Please please, don't be afraid to do this, it is really easy to remove caps, soldering them back on is even easier! If you feel completely afraid of this, simply use some scrap board to practice. Please ask any questions.
  15. These links are dead as are the ones on page 2 of this post. Could someone please upload them to the internet archive so that they will not go away. PLEASE!
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