Recent content by alexGS

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    Macintosh Portable M5120 strange behavior

    I agree with bibilit, faults in battery level sensing sound like hybrid module problems. I’ve fitted replacement hybrids and they have cured such things. I usually have to clip all the pins and remove each pin individually; it’s very difficult to remove a hybrid module intact
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    Three Macintosh Portables that don’t work

    With regard to your third example - I had a Portable recently where one of the three 74AC244 latch chips had failed, related to floppy drive function. I swapped it with one of the other two latch chips and immediately had a display similar to that and no chime. Therefore, I wonder if one of...
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    Portable LCD dims, but evenly all over

    I haven’t seen this before - a non-backlit Portable where the whole display dims perfectly evenly to black in about 5-10 minutes, then recovers from black to normal when powered off for about the same length of time. In that respect (the recovery), it seems the same as Tunnel Vision, except...
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    Backlit Portable with no backlight, v1.3 control panel, where to check please…

    Thanks SuperSVGA - I wasn’t familiar with an electronically-controlled potentiometer. It turned out to be the inverter board faulty, swapping that restored backlight operation. Just coincidence that it failed when I replaced the latch chips
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    PowerBook 500 Series Battery Rebuild Failure (Oops, all dead EMMs!)

    Thanks! :) I got a cheap deal on Eneloop Pro AAs (which I identified as being able to accept a 1A charge rate easily) and swapped that memory chip that I’d ordered. And thanks to jmacz identifying the need for that, it produced a battery pack that actually ‘repaired’ properly with Lind - I was...
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    Macintosh Portable 5126 issues…

    Ok, so right now you have the Sad Mac - CD38 error and no chime when you turn on? I think I would apply some flux and hot air to reflow the square power manager chip (near the right-side trackball connector) - also double-check your capacitor replacements in that area.
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    PowerBook 100 display, LCD_VEE issue but inductors ok?

    Thanks, I’m in New Zealand but price isn’t the problem anyway - it takes me hours to do these, especially when there’s a dust bubble and I have to do it again. I ordered some that claimed to be FSTN, but when it turned up it was exactly the same as other films, so produced the usual results...
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    Macintosh Portable 5126 issues…

    Further to what I said, the error code ending in CD38 is a Power Manager error, so here’s hoping a reset will fix
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    Macintosh Portable 5126 issues…

    Have you tried holding the two buttons on the left side? Should reset the power manager. The process of ‘powering down’ is an important one before installing the RAM card. I hope you had the battery out, power unplugged, AND the battery cover refitted (if you have a 9V battery in there)...
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    Powerbook Duo 280c + Accessories Maintenance

    Thanks! Darn, no wonder it can be so difficult finding LCDs for these machines… the number sounded familiar
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    Powerbook Duo 280c + Accessories Maintenance

    This is an amazing thread - you’ve been extremely thorough, and generous sharing all your great designs. After such efficiency, it’s almost a relief to know you can have accidents too :) I’ve never worked on a Duo, but I feel prepared now. That LCD type seems familiar - same as 540c?
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    PowerBook 100 display, LCD_VEE issue but inductors ok?

    Sorry I didn’t see this earlier. I’ve fixed a few PB100 logic boards with this exact behaviour and I always start by replacing C22 in the corner - it’s involved with producing the LCD drive voltage. I think you will also have to replace the 8x 3.3uF electrolytic caps on the back of the LCD...
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    Powerbook 145 global contrast issues

    Sorry, none of this is any help but just to share some thoughts. I have a similar effect with my Powerbook 100 - the wrong contrast (too dark in my case) and the ‘rolling shimmer’. Seems to go away once it warms up. I thought it was because I used MLCC caps instead of tantalums, but I see you’ve...
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    Backlit Portable with no backlight, v1.3 control panel, where to check please…

    I was having disk drive problems with this backlit Portable that I’ve finally solved - the HDSEL trace was broken between the 6522 VIA pin 16 and 74AC244 latch pin 2. Capacitor leakage was the original cause. While disassembling and reassembling a dozen times during this repair, and around the...
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    PB 5xx original AC adapter re-cap & modern replacement

    It’s a bit depressing isn’t it… I’m almost at the same point myself, can’t cope with the ‘babysitting’. However, I rebuilt a pack a few weeks ago using new Eneloop Pro AA cells (I spot-welded tabs on) and replaced the memory chip. That battery seems to work well: runtime still only about an...
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