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    400k Drive Repair Guide - A Call to Arms!!!!!!

    This company still has some vintage stuff https://www.littlediode.com/components/home.php  
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    According to a similar thread on some other forum, Hall effect sensors may also be the cause of a motor failing to spin when a disk is inserted (please see one of my previous posts on this thread).
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hi guys, just to confirm that the transistor Q107 was indeed the culprit. Today I replaced it with a spare 2SB822 (thanks to JDW) and the drive works again like a charm.
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hello, thanks for the very useful feedback, thanks to it I guess I've eventually found the missing piece of information. Transistor specs: 2SB822 Packaging: "FTR" (see picture) Testing done on the existing one (using a multimeter) is showing it is probably faulty, which is consistent with...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Actually the label on the package of the unit I have is reading “B822”, not “B882”. Is yours different? By the size of the tiny package and the absence of any heat sink, I would not believe it to be high power stuff rated at 3A...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hi guys, follow up notes after replacing the capacitors on the motor board. Honestly, I could not see any difference between before and after. Either way, the disk drive passed more than 2000 random test units without any fault. I'm not saying capacitors may not need replacement (I have...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hi Guys, some updates from my side. Eventually, it seems as though it was indeed the hall effect sensors responsible for the abnormal rpm fluctuation. I replaced the three of them at once, so I can't tell which one exactly was faulty.  RPM are now stable and within the range (slightly above...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Check done on all capacitors of the motor board, all of them in perfect shape, within +/- 10% tolerance (test done off circuit). My feeling is that there's a little of paranoia when it comes to the urge of replacing them...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Quick update for those who are still interested in this topic. The main PCB is definitely not the failed component, there must be something wrong with the motor board, as replacing it with a spare one gives a perfectly functional 100% error free disc drive. 395-396 rpm at track 0, 600-603 rpm...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hi Guys, some additional info about the faulty drive I have... Diagnostic "sonytest" is indicating what seems to be a clear sign that something is not ok with the control signal: for track 00 nominal rotational speed should be 390 rpm, up to 600 rpm for track 79. A working drive is actually...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    I have only tested these unofficial pre-releases with my 128Ks, but - by logic - there should be no reason they should not work on a 512K with original ROM. The software is indeed unstable, but the disk utility "sonytest" is definitely usable and I could not figure out a more complete tool for...
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    You can find the disk images on many sites, such as WinWorld or Macintosh garden. Mind they are unstable and only work on Mac 128K, but they are indeed low level utilities for the 400k drive.
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    400k Drive Repair Guide - A Call to Arms!!!!!!

    Hi guys,  I need your advise and expertise here. Over the past years I have refurbished a few 400k drives. My experience is that they only need to be thoroughly cleaned (especially the r/w head) and lubricated. I also learnt that the mechanical part of the drive is more delicate than one...
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    J1 connector (Plus analog board)

    Hi Guys, same problem on (most of) my classic Macs. After some search, 1:1 replacements exist and are available. Molex > PART NUMBER:19091049  Digi-Key Part Nr WM1606-ND Molex > PART NUMBER:15311046 Digi-Key Part Nr WM1042-ND Both parts seem to be active and available.
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    Sony 800k Drive Repairs

    Hi Guys,  I have this one that is really driving me mad...  I have since many years a Mac Plus (original Mac upgraded), with 800k drive. I turned it on recently and the drive could not eject, usual rotten gears. So I moved on and temporarily replaced it with 800k unit present in external 800k...
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