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 < vintage-macs@googlegroups.com> 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 <ianbatty...@gmail.com> > 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 vintage-macs@googlegroups.com > To leave this group, send email to vintage-macs+ > unsubscr...@googlegroups.com > 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 vintage-macs+unsubscr...@googlegroups.com. > 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 vintage-macs@googlegroups.com > To leave this group, send email to > vintage-macs+unsubscr...@googlegroups.com > 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 vintage-macs+unsubscr...@googlegroups.com. > 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 vintage-macs@googlegroups.com To leave this group, send email to vintage-macs+unsubscr...@googlegroups.com 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 vintage-macs+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
