68kMLA Classic Interface
This is a version of the 68kMLA forums for viewing on your favorite old mac. Visitors on modern platforms may prefer the main site.
| Click here to select a new forum. | |
| Nasty Time Bombs Removed Just In Knick Of Time!! | |
Posted by: macuserman on 2021-12-01 12:39:22  Whew! Cutting it close on this Macintosh II! | |
| Posted by: KGLlewellyn on 2021-12-01 13:15:17 TWO Maxells in one Mac...I would not have wanted to see the results if both went off. Oof. Nice catch! | |
| Posted by: Johnnya101 on 2021-12-01 13:16:30 Wow, that was close! Sidenote: Why is it that some people seem to only find Maxells, and some almost never find them? Was it regional? In probably the 30+ Macs I've come across, I have only found one intact one... | |
Posted by: macuserman on 2021-12-01 13:26:44Wow, that was close!Hmm I've found quite a few I have some machines that did explode already. This is my first macintosh II not sure if I'll keep it or not but I want to play with it at least first and I couldn't wait to get those batteries out when I saw them. | |
Posted by: Johnnya101 on 2021-12-01 15:59:13Wow, that was close!Forgot the edit was removed, so ill reply. Meant to say ive only ever found one maxell. | |
| Posted by: Byrd on 2021-12-01 16:38:16 One is bad enough, two Maxells - that's enough to start a small turf war! I've come across mostly Maxells in early 68K machines, but picked up a B&W G3 recently which had a Maxell. | |
| Posted by: macuserman on 2021-12-02 07:50:18 Hmmm well I may have spoken to soon about saving it just yet lol. I am getting zero signs of life out of it when I try to power it on. | |
Posted by: macuserman on 2021-12-02 07:50:59  Anyone have a test procedure or at least a pinout for the Macintosh II PSU? Be nice to first figure out if it's a PSU or board problem. Board looks really good though so I'm betting PSU. | |
| Posted by: bibilit on 2021-12-02 08:17:00 Have you got a pair of brand new batteries ? The Macintosh II series will need ones to kick the boot process (there's a trick shorting two wires on the PSU connector though) | |
Posted by: macuserman on 2021-12-02 08:44:09Have you got a pair of brand new batteries ? The Macintosh II series will need ones to kick the boot process (there's a trick shorting two wires on the PSU connector though)Ohhh hmm nope, I have some batteries, but didn't put them in this is my first macintosh II that I've played with so I was not aware that they required the batteries to boot. On machines I've used in the past that required it, they would usually power on but just not boot, this isn't doing anything at all. | |
Posted by: macuserman on 2021-12-02 09:15:36Ohhh hmm nope, I have some batteries, but didn't put them in this is my first macintosh II that I've played with so I was not aware that they required the batteries to boot. On machines I've used in the past that required it, they would usually power on but just not boot, this isn't doing anything at all.Just put fresh batteries in it but still nothing so unfortunately that wasn't my issue. | |
| Posted by: joshc on 2021-12-02 09:20:35 Your board has the original electrolytic SMD capacitors, it needs to be recapped. These Mac IIs also have a tendency of problems with their start-up circuit which is documented here: https://www.downtowndougbrown.com/2015/03/explanation-of-the-macintosh-iiiix-power-onoff-circuit/ My Mac II wouldn't start even after it was recapped because of a bad trace in the start-up circuit. | |
Posted by: macuserman on 2021-12-02 09:28:58Your board has the original electrolytic SMD capacitors, it needs to be recapped.Ugh yeah I was thinking I'd need to do that, I guess I need to find a list of caps to order or sit and look them all up on my own but rather just order them and have them on hand before disassembling. | |
| Posted by: macuserman on 2021-12-02 09:32:20 Also not quite sure how to safely remove the adapter to get at the caps and areas around/under it for inspection.  | |
| Posted by: macuserman on 2021-12-02 09:42:31 I know you can get a puller type device or at least I've seen pictures of them for the original CPU chips by itself, but these big adapters no idea how that would even work on one, hate to damage it trying to remove it. | |
| Posted by: joshc on 2021-12-02 10:05:00 That one just pulls up by hand, it’s inserted directly into the CPU and MMU sockets. Just be gentle with it. Cap guides: Rev A: https://recapamac.com.au/macintosh-ii-a/ Rev B: https://recapamac.com.au/macintosh-ii-b/ | |
Posted by: macuserman on 2021-12-02 10:15:42That one just pulls up by hand, it’s inserted directly into the CPU and MMU sockets. Just be gentle with it.Got it I'll give that a try when my caps come in. On another note what's the easiest way to tell if this board is FDHD already? I couldn't seem to find a list of the chip numbers just which chips needed to be changed. | |
| Posted by: joshc on 2021-12-02 10:36:03 It's a case of new ROMs and changing the IWM chip to a SWIM chip. More details on the FDHD upgrade here: 
Macintosh II ROM ReplacementI'd like to upgrade my Macintosh II to FDHD, I have a SWIM chip (to replace the WIM chip), but don't know how to burn the ROMS. The upgrade process I'm trying to do is described in the book: "
retrocomputing.stackexchange.com
Also more detail here upgrading ROM for Macintosh II?hi all, is it possible to replace the ROMs of the Macintosh II with 800k floppy with the version of the one with FDHD? from this 1987-12 - 9779D2C4 - MacII (800k v2).ROM to this 1988-09 - 97221136 - Mac II FDHD & IIx & IIcx.ROM thanks!
68kmla.org
Post a photo here of your chip and someone will be able to identify if its an IWM or SWIM. | |
Posted by: macuserman on 2021-12-02 10:47:50  It says IWM next to the chip but I suppose that doesn’t mean it hasn’t been changed I was hoping it was already modded because the floppy drive looked like a 1.44mb drive. | |
Posted by: KGLlewellyn on 2021-12-07 13:22:46Wow, that was close!I get what you mean. I've never seen one, and I've collected a lot of machines over the years in NW US and UK. | |
| 1 > |