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North Hedge Ned

Different Macintosh in Original User Guide?

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2 hours ago, Dog Cow said:

Andy Hertzfeld's recollection of dates, as with most people, isn't always spot-on and I've found a couple of instances while doing research for the Mac 512K Blog where he had some wrong dates in his Folklore blog.

Nonetheless, it's the date we have, and the date makes sense if the initial target to launch was January 1983 instead of the almost a year later that it slipped to.

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OK - The torx arrived and - JACKPOT!  Both units have Mr. Macintosh inside on the video board, on the EPROM board, and on the Main Logic.  Here are the pix of both units.  Interestingly, the unit with the video issue has a different manufacturer of tube.  Bot units have non functioning floppies.  Maybe a quick fix?  None the less - prototypes for sure - new ones after the Twiggy system!

IMG_5199.JPG

IMG_5201.JPG

IMG_5203.JPG

IMG_5205.JPG

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So, if the dates here are correct the "MacMan" motherboard you have is the May 1983 revision. Per the dates quoted by Dog Cow that puts your motherboard right on the switchover between Twiggy and Sony drives, so whether your particular unit started out as a Twiggy or was built up with a Sony drive initially is probably something you can't really know without knowing more about the provenance of the machines. But in any case there's certainly absolutely no doubt now that these are prerelease developer units in every respect, not just release machines bearing old skins.

 

As to what they're worth, search me. That's for the market to decide I guess. I am curious if the EPROMS on that board have been updated to a shipping release of the 64K ROM code or if they're still pre-release. (IE, will these units run the shipped versions of System 0.97-4.whatever? that a regular 128k will run or not.) They might be "worth" more if they have a prerelease ROM version, even if that makes them worthless from a practical standpoint.

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SO Gorgonops, I wonder how we can tell the EPROMS?  I can't boot from the floppy.  I have a few external floppies around but no system disks to try.  Would like to know the ROM version too.....

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The pic of the TwiggyMac ROMs on 'fritter aren't as detailed as yours, but he listed the markings.

 

The ROM's all have "7T" written in faded blueish felt tip marker on the label, along with the following writing on each of the 4 ROMS:

0 HI - H0 B6ED
1 HI - H1 A04A
0 LOW - LO0F332
1 LOW - LO 1 6CBC

 

 

zQj8M.jpg

 

IMG_5205.JPG

 

 

Between reading Five Different Macintoshes and Macintosh Prototypes I got all mixed up.

 

We've got some info on the Twiggy Version on 'fritter and now two Sony versions of the same board?

Both have Printer/Modem port icons flip-flopped as compared to the shipping version. Do icons match the board's connectors or had they become mislabels?

Is the screen resolution 384x256 or 512x342 at this fork on the timeline?

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Wow, that is incredible!

 

As for the floppy drives, they likely need to be lubricated. The Sony 400k drives are notorious for getting gummed up.

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1 hour ago, Trash80toHP_Mini said:

Is the screen resolution 384x256 or 512x342 at this fork on the timeline?

All versions with 16 bit memory have the higher resolution. This board is *almost* the final product and there's a fair chance it would work with the final shipping ROMs, although of course I can't say that definitively.

 

The only sure fire way to know what the ROM version is would be to either boot it and use a program to dump it to disk for analysis, or to read the ROMs with an EPROM programmer or something. They are standard 27128 parts so finding compatible equipment would not be hard.

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... Note of course that if the code version on these ROMs is significantly older than the latter half of '83 they may well not boot a shipped System version. The Toolbox ROM and the part of the OS that resides in RAM are very tightly interwoven and they were squashing bugs right up to the end.

 

That said, yes, it's totally worth trying to clean and lube the drives if you think you're up to it. Another possible worry is if these are pre-release mechanisms the driver in the ROM may not necessarily be compatible with later drives. As I recall there are actually compatibility issues with different revisions of the internal mechanisms in some shipped machines.

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13 hours ago, North Hedge Ned said:

OK - The torx arrived and - JACKPOT!  Both units have Mr. Macintosh inside on the video board, on the EPROM board, and on the Main Logic.  Here are the pix of both units.  

IMG_5205.JPG

 

You do not have pre-release ROMs.

 

7.0 on the ROM labels means the final shipping version of the 64K Macintosh ROM. These ROMs will have no trouble booting the usual System startup disks once you get your floppy drive working.

Edited by Dog Cow

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Neat-O old machines!

 

The 400K drives may be missing the felt pads or they may need replaced.  Yeah, give then a thorough cleaning and inspection.

Edited by MOS8_030

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What is the best way to recondition the drives?  I fired on up last night - the one with weird video issue unfortunately, and I could hear the read/write heads adjust themselves back into the ready position.  However, insert disk and it is weird - it pushes in, and clicks down almost manually, but no read write sound.  To eject, there is nothing behind the paper clip hole.  However, just a gentle push and voila, the disk pops up and out again.  It's like the first Sony drives took the disk in manually by a push in and down, and the revers to eject.  Nothing powered about it - it seems - not like the production units I believe, which are power-mechanically insert and eject....

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Pics of the drives might be very interesting. I have had, and might still, some very early Sony drives that have some differences from the usually shipping units. Nothing crazy though. The drives were never power-insert, only elect. They just has a very nice mechanism that grabbed the disk and pulled it in "automatically" where as the much, much later "manual" insert drives needed more help from the user.

They way you describe things, the disk is not mounting in all the way because its gummed up. And if it does not seat right, the sensor to detect the floppy being there will not be triggered (its up front). Typically the disk ends up at an angle with the leading edge at the opening being higher up. It is why I will never, ever use lithium grease on drives. It dries up and hardens making it hell to remove but it can be done. I always service the drives with very light amounts of 3-in-one oil after cleaning. Very, very little is needed. These will not be daily use machines after all and the oil can easily be cleaned off even years later.

For the machine with display issues, I suggest you dont power it up anymore. It is likely a cold solder joint that needs a reflow. Very, very common issues. But these joints can create a lot of heat and melt connectors. I have plenty of examples of Macs that did operate seemingly fine, but the cold joints literally burned up and melted the connectors.

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Here's a good starting point for checking the floppy drives.

Also there are PDF copies of the Dead Mac Scrolls floating around on the web.

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Interesting, I'd always assumed the wire to be a an open ground bus for additional discharge safety for ESD over numerous ROM swaps. In the closeups it appears to be a +5V patch needed  to drive the much higher chip count on the adapter board. Is it soldered to the resistor on the supply side/power plane? If not, what's the regulated output supply powering the ROM daughtercard?

 

SonyMacMan-NHN

SonyMacs-MLA-ROMs.thumb.JPG.3b1cc77ebc065e230c22d7680f60b20d.JPG

 

TwiggyMac-AF

TwiggyMac-AF-ROMs.thumb.JPG.843fa8499f4c934853dd8926bdacf130.JPG

 

WAG: very curious, at rev. 7.1 it appears they may have been trying harder/longer to get Twiggy up and running than Sony at 7.0 or that it had gone through more iterations in the process and frozen at that level? Do the markings on the SonyROMs imply/indicate that ROM 1 Hi may have been frozen, ROM 0 Low might have been in the process of being actively debugged and the pair in between somewhere in between the two states and might be frozen at the 7.1 level after debugging was complete?

 

Great stuff, NHN!

 

Edited by Trash80toHP_Mini
Apparently I can no longer typel ;-/

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4 hours ago, unity said:

It is tapped into a capacitor, so yes probably a ground.

Are we talking about that metal fence wrapped around the EPROM board and where it seems to connect to a point labeled "CR3"? A part labeled "CR" is usually a "Current Rectifier", IE, a diode, not a capacitor. (The board has plenty of axial bypass capacitors on it labeled as Cxx, the part at CR3 is physically different and looks like a diode to me.)

 

I can't find CR3 listed on any Mac logic board schematic (there is one on the analog board and it is a diode), googling up a picture of a shipping 128k motherboard I can see that portion of the board is a substantially different so that component may well not exist in the production version.

 

That said it probably is a ground. I'm going to hazard a guess that it's there to act like a fence to divert some electromagnetic interference they thought they might be getting from some other component, like the disk drive or monitor, and they added it in response to some unexplained glitchy-ness that showed up after adding the EPROM board. (Which is why it's made out of wire crudely lashed in place instead of connected to tracks on the PCB.)

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... I am a little curious about the use of four 27128s instead of just using a pair of 27256s inserted directly into the ROM sockets, but as this was 1983 it's possible that the 27256 either didn't quite exist yet or was very expensive. EPROM capacity generally lagged mask ROMs and 32k was a pretty decently large ROM at the time. (Also, according to Folklore they were *really* trying to keep the ROM to 32k until pretty late in the process, so maybe they simply had a ton of 27128s lying around to reuse.)

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Yes, the wire. I assume that is what we are talking about.  And you are right, that is a diode. I did not look at the identifier, looked like a glass capacitor so common on these.  CR3 is on a 128k board but in location B12.

Edited by unity

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MOS8-030 - thanks for the link to the cleaning.  Very useful and will put it into practice this weekend.  I found an old floppy that someone had handwritten on it "System Disk 400K".  So, will see if I can bring life into the working one.  

 

Unity - thanks for the feedback and the input, especially on the non-working display.  So, cold solder joints.... easy fix?  or is this one a nice non-functioning display piece? ... Prototype fish tank?  Have on display in exploded view?  I did notice one strange thing with this one...  The hardware around the base of the yoke is very different than the working one.  The working one has a white ring around it with little magnets place at various locations.  The non-working one has only magnets seemingly taped on (Clear yellow orange tape) magnets.  Also, different labels etc.  The working one (didn't take a pic... yet) was a Samsung I think.  Attached, here is a photo of the non-working unit.

 

Thanks to all for your continued discussion around these units - certainly the mystery unfolds, and the information collection is awesome!

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Hi everyone - Great News!  One of my two 128K Prototypes LIVES!  I pulled the floppy out and gave it a lube up.  Works like a charm.  Found an old disk kicking around with "System Software 400K" written on it.  Turns out to be System 1.1, Finder 1.1g.  Anyhow, the unit is alive and well.  If all goes well, there should be some photos with this post.  With the floppy removed, you can clearly see in the metal an opening large enough for a Twiggy Drive, and the floppy carrier for the Sony plugs that hole up.  Now to figure out if I can fix the other one with the odd bright horizontal lines in the middle of the screen.  Thank for your continued input everyone.

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