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Recent content by PacificState

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    SE/30 floppy drive keeps spinning and ejecting simultaneously on boot

    I've been fixing up an SE/30 and got to the point of repairing the floppy drive. Having replaced the eject gear and lubricated the mechanism, I now find that, from the moment I turn the power on, the drive motors spins up without ceasing while the eject mechanism repeats endlessly - until I turn...
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    M5126 Macintosh Portable Sad Mac (0x14/0xCD36)

    Thanks - I tried cleaning the zebra stripes, albeit only on the top side; it wasn't clear to me that they could be removed without damage. I'm away right now, but I do need to check if the IC drivers are still available...
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    M5126 Macintosh Portable Sad Mac (0x14/0xCD36)

    Progress: I hadn't swapped *all* of the caps over, only those by the power manager - with the three at the top right swapped, it now boots to the checkerboard and disk prompt! However, there's at least one issue - a vertical line just over a third of the way from the left. Separately - the...
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    M5126 Macintosh Portable Sad Mac (0x14/0xCD36)

    Thanks. The new smaller caps arrived, and are installed. With a fully charged battery (verified in another Portable), I get a boot chime then either the same Sad Mac error or a blank screen. If the traces are good, is there anything else I can check?
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    M5126 Macintosh Portable Sad Mac (0x14/0xCD36)

    Thanks! I dug a bit deeper: - The traces actually look OK when I buzz them out ;( I've attached an image - this is right after removing the caps (see below) and I haven't cleaned the pads up yet. - After retrying a few times, I'm getting some intermittent behaviour in terms of booting between...
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    M5126 Macintosh Portable Sad Mac (0x14/0xCD36)

    I'm trying to rescue an M5126 portable which formerly wouldn't start up at all - and so the first thing I did was recap. I've tried to avoid reassembling in full until I'm sure things are working, so I've carefully reconnected (with layers of insulation!) the battery holder on top of the PCB...
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    SE/30 Black screen but works otherwise

    I had this and it turned out to be dry joints on the yoke board.
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    SE/30 Screen Artefacts

    I just built one of the replica boards: - The PALs do get quite hot normally - The RAM test doesn't check the video RAM, I think(?) This kinda looks like a failing bit (or more), but I can't understand why some stuff is drawing correctly. Ideas: - Look at the schematic and recheck the...
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    Macintosh Portable Memory Expansion

    Thanks. What I hadn't understood is that while the Mac (it's a non-backlight M5120) comes with 2MB of memory, 1MB seems to be on the motherboard and (as you hint at) 1MB appears to be on a card I didn't realise was there ;-) Does this mean the expansions differ between the backlight and...
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    SCSI termination and internal/external drives

    Thanks. I'm still kind of confused, to be honest, after looking at the SE/30 schematic. I'd assume that the Mac itself would represent one side and be terminated, but the 50 and 25 pin share the same signals. This makes it conceptually easier (say) if you have a Mac with no internal drive and a...
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    SCSI termination and internal/external drives

    If I have an SE/30 with an internal SCSI drive, then the drive should have termination enabled. However, if I then add an external drive - do I have to disable the internal drive's termination and add it externally (replacing it with a terminator when the external drive is not connected), or...
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    Macintosh Portable Memory Expansion

    I have a Mac Portable M5120 with 2MB RAM, and I'm curious to know what options there are for RAM expansion at this point. MacEffects used to sell an 8MB card (which I believe Techknight designed?) which is now out of stock, but I also think there may have been schematics on this site before the...
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    Macintosh SE/30 logicboard recreation (thread revival)

    And… it’s alive! I ended up socketing the chips, and swapping in the VIAs got it going. Thanks again to Bolle for doing this - and also for revising the board so that the latest rev has the right footprints.
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    Macintosh SE/30 logicboard recreation (thread revival)

    Thanks! I’ve resorted to A/B this board with a known good one;; so far the SIMM signals seem broadly similar. Otherwise, I’m starting to wonder if a bad IC could cause the chime, so I might consider disassembling the ROM…
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    Macintosh SE/30 logicboard recreation (thread revival)

    Got past that issue - there was a *tiny* blob of solder between the vias. With that clear, I get to a boot chime - but then (with a Rominator installed) the sad rising boot chimes and Simasimac. The RAM boots in another board, the muxes (and caps!) are all new parts, I can't see any other...
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