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  1. C

    Broken rheostat on Mac SE

    Shifting image on the CRT for SE is done by adjusting/rotating the metal tab on the neck of the tube. Width adjusting is by core of an inductor coil. None of them is a rheostat.
  2. C

    30Video: New video board for SE/30 / IIsi / more?

    Great progress! You may need a zero delay clock buffer on the clock or at least some termination to compensate long channel and extra loading on the clock signal without alter the timing.
  3. C

    SE FDHD Flyback lived its last day. Suggestions that don't cost more than the machine is worth?

    There are good ones on eBay for less than $100 like this: https://www.ebay.com/itm/196439056626?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=BIgEM56nQ32&sssrc=4429486&ssuid=gybvE_oFT2i&var=&widget_ver=artemis&media=COPY Plus you will get a PSU which typically worth $50 on eBay
  4. C

    SE/30 works great but no sound

    C3, C4, C5 and C6 are actually crucial part of the audio output. With them leaking. The audio will be actually draining and finally disappear.
  5. C

    SE FDHD Floppy Transistor

    There're many variations for 800K 51W but the common circuits around eject mechanism, power-saving switch for 5V(C) and 12V(C), Stepping motor control remain the same even in later FDHD drives.
  6. C

    SE FDHD Floppy Transistor

    Google search: https://tinkerdifferent.com/resources/sony-mp-f-51w-800k-floppy-drive-schematic-vector.116/
  7. C

    SE FDHD Floppy Transistor

    I just jumped into this vintage macintosh business in 2024, before that I was never exposed to anything before late in the PowerPC era.
  8. C

    SE/30 reloaded board hang at boot

    PIC16F87 replacement ADB on this board: mentioned here: https://68kmla.org/bb/index.php?threads/mac-se-adb-controller.38363 , with a QFN-to-PLCC adapter PCB by max1zzz). PCB from max1zzz is here: https://github.com/max234252/PLCC-ADB-Adapter The link to the precompiled binary is also in the...
  9. C

    SE/30 - Design for Drop in Replacement Power Supply

    Hi @mari3311, I think all the power rails are "regulated". The 12V sweeping rail just has an additional LDO (Linear regulator) to further clean-up the noise from the switching noise that is common in this "switching" type of power regulator. Especially PWM controller in old days is oscillating...
  10. C

    SE/30 - Design for Drop in Replacement Power Supply

    Hi @(o';'o), The HITACHI logo is etched on the back side of the PCB: with a likely regulatory number of HCS-40 94V-0 (UL)
  11. C

    SE/30 - Design for Drop in Replacement Power Supply

    The "Singapore" PSUs has a "HITACHI" name on the PCB and according to console5, they are made by Hitachi.
  12. C

    SE FDHD Floppy Transistor

    Refer to the schematic: It is not exactly the same model but from your symptom and PCB trace photo it should match Q7 in the attached schematic: 2SB624-BV4. It is responsible to provide 12V to the eject motor upon control from the controller. If it is shorter then eject motor will be always...
  13. C

    800k drive - swapping eject mechanisms?

    Yes that will work. I did the same a few times.
  14. C

    SE/30 Logic Board and Analog Board Recapped, Boot Chime Quickly Followed By Death Chime, Nothing Shows On Screen

    This seems most likely a RAM problem. It is very possible that some trace finally breaks after all these years
  15. C

    Bad head alignment on 800k floppy drive

    I did destroy one head before the same way. I is pretty much gone. Good luck.
  16. C

    Bad head alignment on 800k floppy drive

    The photo does not look good. Did you bend the upper part of the head too hard when you clean the head? Here is a photo of a working 800k drive:
  17. C

    Bad head alignment on 800k floppy drive

    Did you move the Zero Track Sensor (ZTS) during the cleaning? If so then it is most certainly misaligned. Check Zero Track alignment in https://tinkerdifferent.com/threads/superdrive-floppy-maintenance.549/page-2 I followed these steps and fixed a few 800K/1.44M drives.
  18. C

    CRT on Mac Plus -- rows randomly offset by 1-2 pixels

    Did you do anything to rule out the problem on the Logic board? Could you upload a hi-res photo around the video circuitry area? (UA8~UG8)
  19. C

    SE/30 reloaded board hang at boot

    Problem solved with a new ADB replacement:
  20. C

    SE/30 VIA chip replacement

    I recently worked on a SE/30 Reloaded board. The ADB chip from the donor board is bad so I used a PIC16F87 replacement ADB on this board. (mentioned here: https://68kmla.org/bb/index.php?threads/mac-se-adb-controller.38363 , with a QFN-to-PLCC adapter PCB by max1zzz). I noticed that if I use...
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