512k Fat Mac - Seeking Suggestions for Repair and Selling

[Star Lake]

I am the original owner of a Fat Mac, which has resided in my closet for decades and was in great condition and working fine when I gave it a quick check about a year ago. However, when I took it out of the closet again more recently, something had changed. I got nothing on the screen and only heard a faint sound from inside the Mac. It may have been something like a clicking sound -- but that is more of a guess than a clear memory. The external battery in the back is clearly no longer working, so I took it out to prevent any corrosion damage.

I will probably be selling it, but I would prefer not to have to sell it as non-working, if there might be a potential easy fix to restore it to the condition it was in when previously taken out of the closet. So I am wondering if anyone here can provide some advice on any simple things I can try -- since it seems minimal harm should have come to it while simply residing in a closet, unused, for a year.

I am not educated or trained in computer hardware repair and am not a computer scientist or engineer of any kind. I have only done very basic upgrades like installing memory, video and audio cards, fans and drives, etc., on desktop PCs, but never done anything inside a Mac. So unfortunately, I am too unskilled and busy with other things to conduct a major diagnostic or repair project. But after reading a post somewhere saying that simply tapping on the side of an old Mac can fix a "cold solder" (whatever that is) and get a Mac running again - I figured it wouldn't hurt to ask for suggestions. In case it matters, I am located in the southern suburbs of the Minneapolis-St. Paul metropolitan area in Minnesota, USA.

The Fat Mac, keyboard, mouse and external floppy drive have long resided inside the original Macintosh carrying case which is also in excellent condition. I also have a lot of Fat Mac software, manuals, printers, etc.

In addition, I have a Mac Classic in excellent condition, with a lot of software, etc., that worked great last time I checked on it.

Any thoughts or suggestions regarding 1) a potential repair strategy for a novice or 2) some options for how and where to best sell the Macs, software, manuals, printers, etc., would be very much appreciated

 

[olePigeon]

Solder is usually tin or an alloy of tin & lead. With care and precision, you can safely melt it without also damaging sensitive computer components. So if you imagine your typical computer component with metal legs that go through tiny holes in the circuit board, the solder is melted to create a bond between the component and the circuit board. A "cold solder joint" happens when that bond has broken (perhaps from expansion and contraction due to temperature change, or from sudden or violent motion), allowing the legs of the component to shift and move about because they're no longer secured. Basically, tapping or slapping the side of the computer may cause the component to shift and create a temporary connection, allowing the computer to work. The risk, of course, is short circuiting or blowing out components. Because it's so small, they can be very difficult to detect. You can see in the picture below how two of the solder joints are cracked.



The likely fault on a 512k with no video would be the analog board. It's responsible for both power and video (among other things.) Many compact Macs of that era need new capacitors, as they tend to get old and start to leak. However, sometimes the capacitors are just fine, and indeed it can just be a cold solder joint.

I would see if anyone in your area also has a compact Mac and can loan you a working analog board. That will help you rule out the problem being in the main logic board.

Although a shotgun approach to repairs is not recommended, a "recap" (replacing all the capacitors) is not always a bad idea anyway, as it can be seen as preventative maintenance as much as it is a repair. It also will address any cold solder joints that might have appeared around capacitors.

As far as repairs ago, I'm afraid a soldering iron is in your future for either cold solder joints or bad capacitors. There are people who do recapping services if you're willing to spend some extra money. You can then figure that cost into the price of the computer if you decide to sell it.

Goes without saying that you have to be very, very careful when opening the computer as it has a CRT inside. Make sure the CRT is discharged. If you don't know how to safely discharge the CRT, just leave it unplugged and come back to it the next day. That is the safest way.

If you want to look inside, lay the computer face down on a towel. There are FIVE screws; 2 in the handle, 2 in the rear, and 1 inside the battery compartment. Don't forget the screw in the battery compartment. Also, do not mix up the screws. The 2 in the handle are different thread than the 2 on the rear. You'll need an extra long Torx T15 to undo the screws.

Do NOT pry apart the bucket from the bezel using a screw driver. You'll only damage it. It may be stubborn, but should be able to pry them apart using just your hands. I typically hold the bezel with one hand, then pull and wiggle the bucket via the handle to loosen it.

 

[olePigeon]

If you're curious about learning how to solder, then I can't recommend enough the old PACE tutorials.

https://www.youtube.com/playlist?list=PL926EC0F1F93C1837

 

[oldpcguy]

I am the original owner of a Fat Mac, which has resided in my closet for decades and was in great condition and working fine when I gave it a quick check about a year ago. However, when I took it out of the closet again more recently, something had changed. I got nothing on the screen and only heard a faint sound from inside the Mac. It may have been something like a clicking sound -- but that is more of a guess than a clear memory. The external battery in the back is clearly no longer working, so I took it out to prevent any corrosion damage.

I will probably be selling it, but I would prefer not to have to sell it as non-working, if there might be a potential easy fix to restore it to the condition it was in when previously taken out of the closet. So I am wondering if anyone here can provide some advice on any simple things I can try -- since it seems minimal harm should have come to it while simply residing in a closet, unused, for a year.

I am not educated or trained in computer hardware repair and am not a computer scientist or engineer of any kind. I have only done very basic upgrades like installing memory, video and audio cards, fans and drives, etc., on desktop PCs, but never done anything inside a Mac. So unfortunately, I am too unskilled and busy with other things to conduct a major diagnostic or repair project. But after reading a post somewhere saying that simply tapping on the side of an old Mac can fix a "cold solder" (whatever that is) and get a Mac running again - I figured it wouldn't hurt to ask for suggestions. In case it matters, I am located in the southern suburbs of the Minneapolis-St. Paul metropolitan area in Minnesota, USA.

The Fat Mac, keyboard, mouse and external floppy drive have long resided inside the original Macintosh carrying case which is also in excellent condition. I also have a lot of Fat Mac software, manuals, printers, etc.

In addition, I have a Mac Classic in excellent condition, with a lot of software, etc., that worked great last time I checked on it.

Any thoughts or suggestions regarding 1) a potential repair strategy for a novice or 2) some options for how and where to best sell the Macs, software, manuals, printers, etc., would be very much appreciated

I hate to say this but there's not a lot you can do without electronic troubleshooting. If I had to guess I would say some of the capacitors have gone bad on the logic board. They tend to be the parts which fail over time, even when not in use. Recapping isn't difficult but I wouldn't recommend it to someone who has never soldered before (unless they were doing so as a learning experience).

IMO you'll need to sell it as non-functional. Whatever you do do not just dispose of it. There are people who will gladly take it off your hands.

Goes without saying that you have to be very, very careful when opening the computer as it has a CRT inside. Make sure the CRT is discharged. If you don't know how to safely discharge the CRT, just leave it unplugged and come back to it the next day. That is the safest way.

If you're going to attempt any type of troubleshooting pay attention to this!

 

[olePigeon]

@oldpcguy In my experience with the 128k, 512k, and Plus, it's less likely to be a capacitor on the logic board and more likely to be something wrong with the analog board. The three axial caps are less likely to leak (but not impossible), and caps from that era are generally more reliable. But I wouldn't rule it out, of course, and should be checked anyway.

If he can somehow borrow and swap out the analog board, that'd would narrow it down for sure. In fact, if he can just get a working analog board and swap it out permanently, then he's all set. He could sell both the working machine and a separate non-working analog board that someone might be interested in recapping.

 

[Timo W.]

If it worked a year ago and is now clicking, the analog board needs new caps. That's the most common problem with these and well-known. No need to speculate, really. But I doubt that is something you can do yourself based on what you wrote about your skills. Maybe you know someone who can do it for you? (note that whoever does it needs to know how to safely handle a CRT)

In addition, I have a Mac Classic in excellent condition, with a lot of software, etc., that worked great last time I checked on it.

The Classic has a battery and SMD caps inside that will slowly destroy the mainboard when not taking care of. I somehow doubt it does still work, so better give it a test, too.

 

[oldpcguy]

@oldpcguy In my experience with the 128k, 512k, and Plus, it's less likely to be a capacitor on the logic board and more likely to be something wrong with the analog board. The three axial caps are less likely to leak (but not impossible), and caps from that era are generally more reliable. But I wouldn't rule it out, of course, and should be checked anyway.

If he can somehow borrow and swap out the analog board, that'd would narrow it down for sure. In fact, if he can just get a working analog board and swap it out permanently, then he's all set. He could sell both the working machine and a separate non-working analog board that someone might be interested in recapping.

I believe the logic board needs to be operating in order to generate the video information to activate the video circuitry on the analog board.

Here is a video which illustrates the issue (it even speaks to cold solder joints and reflowing them):

Macintosh Plus power supply troubleshooting and repair​

Regardless it appears the OP does not possess the skills / tools necessary to perform capacitor replacement on either the analog or logic board. I don't know where the OP resides but if it's within the states and he feels like shipping it to me I would be happy to replace the caps for him.

To the OP, here is what we're referring to. These are SMD capacitors that I am replacing on an LC system. The first is a picture of the capacitors prior to removal. There is some faint traces of corrosion on the right leg of C13 (the silver tab right above the three, sorry it's not clear the picture was taken to focus on the top of the capacitor and not the logic board itself) and none visible for C14. The second picture is the mess that was found after removing the capacitors. As you can see both had leaked but kept it hidden well. The third is the same area after cleaning. If you look closely at the solder pads for C13 you'll see they have been damaged from the capacitor leaking (they should be smooth like the pads for C14).

 

[GiGaBiTe]

OP, you should put your location in your profile so we know where you are. It'd help to point you to someone that can fix your machine that's nearer you.

Shipping these machines cross country is expensive and hazardous to the machine. Many a mac have been destroyed in shipping.

 

[Star Lake]

To olePigeon, oldpcguy, Timo W. and GiGaBiTe: Thank you all so much for your very thoughtful, informative and wise responses. The quality and detail of your responses was terrific and speaks very well for this forum.

I thought it would be best to address all of your responses in this one post, so I hope I am not breaking any forum rules or degrading the forum by being so verbose.

I re-checked the Fat Mac; it still fails to display anything on the screen. But now I can provide a slightly better description of the sound it makes. When turning on the Fat Mac, the sound I hear is a low volume, continuous medium frequency/pitch sound. The sound is broken up into relatively rapidly repeated individual pulses of sound – but it doesn’t sound like clicking or a flup flup flup noise to me.

I mentioned in my previous post that I am located in the southern suburbs of the Minneapolis-St. Paul metropolitan area in Minnesota, USA. However, I cannot find a way to enter that information, or anything else, into my profile. I found my way to “preferences>your profile” but could not find any way to enter information.

It turns out that I have soldered before, several decades ago – it was probably to fix some radios or some other electronics. I think the soldering gun, inherited from my grandfather, is hiding in my basement somewhere. But, as some of you have gathered, I am not anywhere near being in your “league” as far as Macintosh repairs. I’m not even in the “Little Leagues” (e.g., a baseball league for little kids in the USA).

After reading your replies, you have helped clarify that maybe I shouldn’t have even hinted at the possibility of me attempting any kind of substantial repair at all. It’s not so much that I wouldn’t ever be willing to give a repair like you’ve suggested a try, it is just that, priority wise, I don’t have time now or in the near future – especially to get up to speed to intelligently do troubleshooting, replace caps, etc. In addition to preparing to search for a new home in a far away place and everything else it takes to sell a house and move to a far away state – maybe Arizona, I have maybe a hundred different types of “projects” like this where I am attempting to prepare, list and sell things before I move. (Here is an example that retro/vintage gamers may find interesting). Plus I don’t like to take too much time away from volunteer work (here is a computer-related example in case it might be of interest).

Thanks to your replies, I now realize that, for me, to even get ready to begin a significant troubleshoot/repair, I would need to learn a lot of new vocabulary, and skills, and find the correct torx screwdriver (no luck after visiting 4 hardware stores) and possibly other tools, figure out how to get inside the Mac case and avoid electrocuting myself, figure out how to take things apart and put the computer back together, figure out what “caps” I would need, figure out where/how to get them, likely have to learn how to troubleshoot a specific model, and so much more.

It’s just that, having seen the Fat Mac working just fine so recently, (might have even been less than a year), it seemed like a shame to have to sell it as a non-working Mac. I suppose it was just wishful thinking that a computer that degraded while just resting in a closet a short time – might have an extremely easy fix.

I have no idea what I could sell a Fat Mac for when the display does not even turn on, but otherwise appears to be in very good condition. But I am assuming that even just paying to safely ship and insure it somewhere round trip (e.g., for troubleshooting and repair) may cost more than I could sell it for. But since I am in Minnesota (as opposed to Silicon Valley, LA, NYC, etc.), it may be difficult to find someone local that wants to buy it.

Oldpcguy: thanks so much for your offer regarding replacing the caps. However, I don’t know if I could sell it for the cost of round trip shipping and insurance cost, even if replacing the caps “fixed” the Fat Mac. Plus, I’m sure you would want some reasonable reimbursement for the repair.

I would indeed like to sell the Fat Mac, lots of software for it, lots of manuals for it, printer(s), etc., along with my other items, to help afford to move to a warmer climate. Any practical suggestions on how to sell these given the reality of my location and the Fat Mac’s condition would be sincerely appreciated.

In response to some of your specific comments:

Regarding the possibility of knowing or finding someone with a compact Mac or someone who could loan me a working analog board:

Unfortunately, I am just a retired hydrogeologist (environmental scientist) that has no acquaintances or contacts with anyone locally who has a vintage Mac, knows anything about old Macs, has an analog board, etc. Way back when I purchased the Fat Mac in California in about 1985? I volunteered part time as a non-computer-expert to assist a group of Mac software developers. My role was simply to bring an educational (former teacher), technical (non-computer) background, business and consulting background to a group who had very sparse experience outside of programming. I can’t remember if any of them ever had hardware skills, but that was a lifetime or two ago and I have lost contact with all of those folks. And sadly, hydrogeologist acquaintances of mine don’t know anything about vintage Macintoshes.

I checked and discovered that my Mac Classic is actually a Mac Classic II – so I hope it will be still working great next time I check it. I haven’t decided whether to sell it or not. If I knew an easy way to actually get it sold for a good price before I move, without a ton of work and time spent, I would consider it – and the same for the software, manuals, printer, etc.

I have attached some thumbnails of photos related to the Fat Mac.


I

 

[oldpcguy]

Oldpcguy: thanks so much for your offer regarding replacing the caps. However, I don’t know if I could sell it for the cost of round trip shipping and insurance cost, even if replacing the caps “fixed” the Fat Mac. Plus, I’m sure you would want some reasonable reimbursement for the repair.

Nope, I'd be happy to do so at no cost (aside from return shipping). I enjoy working on these old Macs and would be happy to do so for one of the earliest models.

I have attached some thumbnails of photos related to the Fat Mac.


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Looks to be in great shape. Believe it or not the system, even not working, has some decent value given you have the mouse, keyboard (especially the keyboard cable, it is NOT a standard telephone cable), external drive, and carrying bag.

 

[GiGaBiTe]

It turns out that I have soldered before, several decades ago – it was probably to fix some radios or some other electronics. I think the soldering gun, inherited from my grandfather, is hiding in my basement somewhere. But, as some of you have gathered, I am not anywhere near being in your “league” as far as Macintosh repairs. I’m not even in the “Little Leagues” (e.g., a baseball league for little kids in the USA).

While a soldering gun would probably work, it's not something I'd recommend. The temperature isn't very consistent on those old guns, and the weight would make it ham-fisted to work on small areas of a circuit board. I'd recommend a Weller soldering station where the temperature can be varied.

Thanks to your replies, I now realize that, for me, to even get ready to begin a significant troubleshoot/repair, I would need to learn a lot of new vocabulary, and skills, and find the correct torx screwdriver (no luck after visiting 4 hardware stores) and possibly other tools

If you have a Walmart near by, they sell a precision screwdriver kit with an extension that will work. You may want to buy two to have two extensions, just one will barely reach. This will have most every bit you'll ever need.

Robot or human?

figure out how to get inside the Mac case and avoid electrocuting myself, figure out how to take things apart and put the computer back together, figure out what “caps” I would need, figure out where/how to get them, likely have to learn how to troubleshoot a specific model, and so much more.

All of this information is well known, and has been for a very long time. If you don't know, just ask and someone can tell you. There are also other forums with other experienced mac users you can look to for help too. 68kmla, Vogons and Tinker Different.

It’s just that, having seen the Fat Mac working just fine so recently, (might have even been less than a year), it seemed like a shame to have to sell it as a non-working Mac. I suppose it was just wishful thinking that a computer that degraded while just resting in a closet a short time – might have an extremely easy fix.

This is the norm in the vintage Mac community. Any serious vintage Mac enthusiast/collector knows that virtually every machine today needs to be restored prior to use. It's a pay to play hobby. The community has gone so far to reverse engineer Mac logic boards to make new runs of logic boards that were destroyed by capacitor and battery bomb damage. The fact that you removed the battery before it leaked already makes your machine hold more value.

I have no idea what I could sell a Fat Mac for when the display does not even turn on, but otherwise appears to be in very good condition. But I am assuming that even just paying to safely ship and insure it somewhere round trip (e.g., for troubleshooting and repair) may cost more than I could sell it for. But since I am in Minnesota (as opposed to Silicon Valley, LA, NYC, etc.), it may be difficult to find someone local that wants to buy it.

Round trip shipping and insurance alone would greatly exceed the value of the machine. I'd only recommend getting it repaired if you want to keep it for personal use. The last SE I repaired was something like $200 in shipping on top of hundreds of dollars in parts and labor.

But never discount different areas of the country for not having any interest. There are people all over the states, and all over the world for that matter that restore and use these machines.

I would indeed like to sell the Fat Mac, lots of software for it, lots of manuals for it, printer(s), etc., along with my other items, to help afford to move to a warmer climate. Any practical suggestions on how to sell these given the reality of my location and the Fat Mac’s condition would be sincerely appreciated.

You could list it in the "Vintage Computer Items for sale or trade" section on this forum, Amibay and Ebay. Just say what the problems are and start high and slowly lower it until it sells.

I checked and discovered that my Mac Classic is actually a Mac Classic II – so I hope it will be still working great next time I check it. I haven’t decided whether to sell it or not. If I knew an easy way to actually get it sold for a good price before I move, without a ton of work and time spent, I would consider it – and the same for the software, manuals, printer, etc.

If it does still work, it may not for long unfortunately, unless you take action now.

All of the compact Macs suffer the same problems with heat related issues, but the Classic II has the additional nightmare of an internal PRAM battery on the logic board, and the notoriously bad early SMD capacitors that leak corrosive electrolyte. These machines are often found battery bombed to death, and/or additionally damaged by the leaking capacitors. I WOULD NOT recommend powering that machine on at all until it is disassembled and carefully inspected. If electrolyte has leaked (and you can be assured it has to some degree), the board being powered on will cause electrolysis damage because the electrolyte is also conductive.

The capacitors in the power supplies in the later compact Macs are also notorious for leaking, with the additional problem that some of them have corrosive and conductive glue in them that causes the PSU to malfunction.

These are all problems that will happen, not if they will happen. The longer you wait, the more risk of the machine being destroyed by rot.

 

[olePigeon]

If you're interested in getting back into soldering, there are several low cost USB chargeable soldering irons on the market now. They're much cheaper than a Hakko or something like that, and they have several modern features such as temperature control, temperature profiles, and relatively quick heating.

 

[Star Lake]

oldpcguy, GiGaBiTe and olePigeon:​

Thank you all so much for your very thoughtful and helpful replies!

 

[Star Lake]

In case someone in the forum is interested, I have now listed the items (described and shown in this thread) for sale on eBay.

 

[oldpcguy]

In case someone in the forum is interested, I have now listed the items (described and shown in this thread) for sale on eBay.

Aside from the mouse sticker it looks very clean.