Keith, Have you seen or heard of electrolytic capacitors on pre-SE/30 compact Macs leaking? These would all be through-hole capacitors, which hold up quite well compared to SMD ones. Apple didn't switch to SMD caps on compact Macs until the SE/30. The general consensus on earlier compact Macs is to leave the caps alone unless there is a (rare) problem (e.g smell a fishy smell). Of course, they can and will die eventually, and leak their fluid. It's just not common.
*Much* more common is the battery leaking, and you noted that problem. That's my vote. Or if it's a Plus or has any kind of internal upgrade, the SIMMs or upgrade board may be loose. Best, Jerri On Tue, Feb 5, 2019 at 4:12 PM 'Keith Jamison' via Vintage Macs < [email protected]> wrote: > Hi Ian, > > I'm with Jerri Kohl on this. > > A SAD MAC indicates an issue with the hardware. That means it could be > missing or faulty RAM, leaked capacitors or some other faulty component. > That is always down to the digital board (logic board, motherboard). > > The fact that it powers on does not exclude the analog board where the > power supply and video circuits are found. Some of the power circuits may > be out of tolerance (age related and a result of temperatures and old > components) and as such they may not be feeding the correct voltages back > to the digital board. > > If this is what you see: > Sad Mac icon <http://apple.wikia.com/wiki/Sad_Mac_icon> > > Sad Mac icon > > A Sad Mac is a symbol used by older-generation Apple Macintosh computers > (hardware using the Old World ROM), sta... > <http://apple.wikia.com/wiki/Sad_Mac_icon> > > Then it would be helpful to know what the two numbers are under the sad > Mac. > > The symbol for no system folder (i.e. no disk with a system file) is this > (see Figure 1): > > How to Generate Floppy Disks for Old Macintosh Computers - Hardware Secrets > <https://www.hardwaresecrets.com/how-to-generate-floppy-disks-for-old-macintosh-computers/> > > How to Generate Floppy Disks for Old Macintosh Computers - Hardware Secrets > > Gabriel Torres > > Did you buy an old Macintosh computer, but it didn’t come with programs > and the operating system disks? In this ... > > <https://www.hardwaresecrets.com/how-to-generate-floppy-disks-for-old-macintosh-computers/> > > If you are not handy with a soldering iron, you may be able to find > someone local, or certainly within a reasonable distance who can replace > the electrolytic capacitors and any other damaged components. > > This image shows some deposits around the capacitors on the digital board: > > http://crasno.ca/articles/img/MacIIciBadCaps.jpg > > This image shows the rear of the Macintosh Plus > > http://www.vectronicscollections.org/apple/images/macintoshplus/msnap2.jpg > > If you zoom into the image, you can see in the left hand column Model > Number M0001A which identifies the Plus. > > This image shows a Macintosh 512k: > > > http://www.vectronicscollections.org/apple/images/macintosh512k/macintosh512K_msnap2.jpg > > Over towards the power switch, above the characters 512K is the Model > Number M0001W > > This image shows a Macintosh 128k: > > > https://www.filfre.net/wp-content/uploads/2016/09/AwgXEL5dnYbIVWuo.medium.jpg > > Again, towards the power switch, the Model Number is given as M0001 > > This is important for the following reason. Some folks chose to upgrade > their original Macs by sending it back to Apple. Apple removed the original > logic board, installed a new logic board and, as some external connections > may have been different from the original, they installed a new back to > reflect the actual logic board inside. > > This means that some original 128k and 512k Macs have Plus logic boards > and Plus backs while the front of the casing still looks like a 128k or a > 512k. The front casing should also have a SERIAL NUMBER label beside the > brightness control, you will have to tip the computer carefully onto it's > back to see the label and it likely refers to the original build, not the > upgraded version. > > If you have a 128K, 512K or Plus, there should be a battery compartment > above the power switch. The compartment is a little larger than a AA > battery. Hopefully there is no battery in there, or, if there is a battery, > hopefully it hasn't leaked. > > I'm still leaning towards some leaky electrolyte on the digital board. It > can bridge circuit connections and cause spurious short circuits. > > Hope this helps you to determine the model and diagnose the fault. > > Keith > > > > > On Sunday, 27 January 2019, 11:25:21 GMT, Ian <[email protected]> > wrote: > > > Hi, folks, > > I have an early Mac, it has the square RJ11 keyboard connector, DB mouse > connector and a single floppy drive. > > It boots to the screen, but displays the "sad mac" icon, as I do not > have a startup disk. > > I understand that this is a 400 k, single-sided disk. > > I do have another Mac, but it's an SE30 with the double-sided > higher-capacity drives. > > So, (i) can I get a suitable disk from you or one of your members, or > (ii) is it possible to make a 400 k boot disk on my SE30 (I have plenty > of spare disks). > > I do have a complete set of setup disks for System 6 and System 7, but I > understand that these will also have the incompatible high-capacity format. > > Thanks in advance, > > Ian Batty, Secretary, Historical Radio Society of Australia, > > 79 Rosebud Avenue, > > Rosebud, 3939, Victoria > > mob' 0402 736 527 > > > --- > This email has been checked for viruses by AVG. > https://www.avg.com > > -- > -- > ----- > You received this message because you are a member of the Vintage Macs > group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to vintage-macs+ > [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > --- > You received this message because you are subscribed to the Google Groups > "Vintage Macs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > > -- > -- > ----- > You received this message because you are a member of the Vintage Macs > group. > The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our > netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml > To post to this group, send email to [email protected] > To leave this group, send email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/vintage-macs > > Support for older Macs: http://lowendmac.com/services/ > --- > You received this message because you are subscribed to the Google Groups > "Vintage Macs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- ----- You received this message because you are a member of the Vintage Macs group. The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/vintage-macs Support for older Macs: http://lowendmac.com/services/ --- You received this message because you are subscribed to the Google Groups "Vintage Macs" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
