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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    It should be possible! I mean this thing runs on a single USB-PD charger right now so integrating a better and modern power supply circuit on a brand new PCB would be really kickass! I also think everything except the flyback and the CRT connectors can be replaced with SMD resistors and probably...
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    Mac Classic with a Pi & USB-C

    I've modified `dtparam=vactive=342,vsync-invert` from 342 to 384 to have a proper 4:3 aspect ratio. After adjusting the vertical size potentiometer it seems to work well!
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    Mac Classic with a Pi & USB-C

    Hi! Sorry for the reply, Yes I've thought about trying out grayscale but I haven't got the time to replicate the grayscale neck board yet. Soon maybe?
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    Mac Classic with a Pi & USB-C

    Also the analog board voltage hooks schematic buried in the previous thread: WARNING: If you don't know how to deal with high voltage stuff, please stay away from this thread. I am not liable for any lethal/non-lethal injuries or damages resulting from the use of this information.
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    Mac Classic with a Pi & USB-C

    Can't believe I forgot to post it but here's my config.txt for the rpi 4 if anyone wants to replicate: kernel=rpi4-u-boot.bin dtoverlay=upstream-pi4 arm_boost=1 dtoverlay=vc4-kms-v3d-pi4 dtoverlay=cma,cma-256 max_framebuffers=2 arm_64bit=1 gpu_mem=16 boot_delay=0 force_eeprom_read=0...
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    Mac Classic with a Pi & USB-C

    After more than a year of service as a Raspberry Pi 4 home server, It's still going strong :) I've added a adb2usb converter courtesy of https://github.com/tmk/tmk_keyboard/tree/master/converter/adb_usb The CRT has been continuously running ever since, it's noiseless and only consumes 30W of...
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    WARNING: If you dont know how to deal with high voltage stuff, please stay away from this thread. I am not liable for any injury or damages resulting from the use of this information. With that out of the way, this is the culmination of all my mods to make the Early Classic Analog Board run...
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    I will list down the mods in a modified schematic of EAB later soon, hopefully folks can try it to save classic analog boards that are screwed by their broken PSU circuits :)
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    Yes, i retained the LM317, but i removed the 12v reg for efficiency's sake and combined all 12v rails into one, including the one on the heater, the 12v rails on the deflection IC and the softstart RC circuit in LM317's ADJ pin. I supplied the usb-pd's 20v to the input of LM317 and it seems to...
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    Mac Classic with a Pi & USB-C

    I'm using a custom build of minivmac beta, running on SDL2 and renders dirctly on gpu accelerated framebuffer without Xorg
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    Mac Classic with a Pi & USB-C

    And we did it :D
  12. W

    Mac Classic with a Pi & USB-C

    @Nixontheknight yes, i actually have figured out that part already! I just need some parts to arrive today so that i can display from the RPi 4 :D
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    Okay, after some tweaking, it seems that the LM317 and its adjacent passives are important for limiting the current of the 31v rail. Now it's fixed, hopefully.
  14. W

    Mac Classic with a Pi & USB-C

    Finally, after the troubles i had in this thread, I'm now able to power the early Mac Classic's analog board with USB Type C! (Right now im using its fixed up logic board that is also powered by USB Type C for demonstration purposes). Final aim is to make it like what they did here. But with a...
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    Okay... Kinda feeling like an idiot now... So there's probably nothing wrong with the A/B.. I adjusted the HOT voltage, the BOMARC schematics suggested +31V but when i turned the voltage down the bad smell seems to have gone away and the horizontal width has reduced. There's still some noise but...
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    After some cleaning and removing some gunk, i've revived the LB with alternative power regulators, but unfortunately im still getting the same herringbone kind of pattern, the same as im getting with the Pi4, as well as the really wide output. Any ideas folks?
  17. W

    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    So yeah, when i try to display a full picture, the area around the MOSFET starts to smell quite bad... and only smells bad when i show a almost-fully white image. And it has a very bad shimmering effect as well.. not sure what to do next honestly Also tried to adjust the width coil thingy but...
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    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    Just FYI, i was able to do 3d acceleration on this setup + SE CRT&AB.. kinda useless but at least it's less burden on the Pi4's CPU :)
  19. W

    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    No problem! Any help is very appreciated! :D
  20. W

    Diagnosing a Classic Mac in a weird situation (Early Analog Board)

    I only have a 2 channel oscilloscope, should i try checking hsync and the pixel clock perhaps?
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