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    Help identifying Apple Monitor H-card components

    Looks like a low profile potentiometer.  If you can determine the value in ohms and the lead spacing, you should be able to select and buy a replacement from an electronic parts supplier.  If you have the schematic and know the part identifier you should be able to figure what value is needed.
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    Astec PSU Question

    Those Rifa filtering caps do not come in that form, which is typically used for electrolytic caps.  The ones that are failing have some kind of epoxy fill inside a rectangular plastic case, and it degrades over time which causes the problem.  It can be very smelly when they fail, with lots of...
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    RAM type reliability

    Make sure the voltage being used to drive the memory under test is within spec for that specific memory type.  I've seen some DDR memory that really wanted a few extra tenths of a volt to run reliably on certain motherboards.
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    RAM type reliability

    Do you know if your tester is really reliable at DDR speeds?  If its PCB layout isn't right you could have issues.  Also it might be good to verify its power supply is in spec.
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    SCSI2SD and CD-ROM Emulation?

    Is the bus termination correct?  Is there either double termination (both the SCSI2SD and another terminator) or no termination?
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    Mac 128k Keyboard Recapping - 1uf 63V

    That cap doesn't need a voltage rating of 63V at all.  They probably had a big stock of them and just selected them for the capacitance value.  I suspect that the ESR rating isn't much of a factor either, since the keyboard is not a power supply that needs smoothing, nor is it operating at high...
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    Help required with Logic board component IIgs

    You can double check the part on the SE/30 board by seeing if pins 1&8, 2&7, 3&6 and 4&5 have continuity.  Since they are inductors, the resistance shouldn't be very high.
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    Help required with Logic board component IIgs

    Since one side of each of the inductors inside that part goes straight to the ADB connector, it might be good to check that pin 3 of the connector itself isn't somehow sorted to ground.
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    Ethernet Hub Repair

    I've had hubs go bad before, they would loose individual ports.  Since I had other unused hubs available, I never bothered to try and diagnose it. I also have had switches from Linksys/Cisco and Dell fail due to power supply issues.  I replaced the bad capacitors and they worked again.  However...
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    Purpose of purposefully omitted component on IIsi board?

    Looks like it could be an alternate form factor if Y1 isn't available, Y2 would be populated?
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    Apple IIGS graphic glitches

    What happens if you switch it into text mode by selecting the text control panel (command-control-escape) from the glitched graphics mode, then exit from it back to graphics mode?  Do you have a way to cool off the VGC when it is glitching to see if it is temperature related?
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    Apple IIGS graphic glitches

    You could try running the RAM diagnostics from the diagnostics disk to see if that turns up anything about banks $E0 and $E1.
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    Apple IIGS graphic glitches

    I can't tell exactly, but it looks like the offset of the dislocated pixels is maybe 8?
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    Apple IIGS graphic glitches

    Looks like an addressing error where it is drawing a column too early in the scan, pulling the data from a later column.
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    What is the current view on these hard drives?

    I've had good luck with my old SCSI HDDs.  I've not heard of "the awful sticky rubber goo problem", so I don't know to what you are referring.  Power them up and see if they respond.
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    IIGS power supply 12v at 11.5, should I worry about it>

    Taking a quick look at the IIgs schematics, about the only thing on the motherboard that uses +12V is the speaker driver circuitry.  It is also supplied to the card slots, but a CFFA probably doesn't use that voltage, so you may not care that it is a bit low.
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    IIGS power supply 12v at 11.5, should I worry about it>

    Well, the +12 supply is only 4% low, so may be within tolerance, but maybe only until you attach some hard disks that need it.  Some quick searching didn't turn up a schematic.  Since you are going to use a CFFA and nothing else you are probably good to go.
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    Mac IIsi internal speaker distortion

    Do you have an oscilloscope available?  If you sent a pure sine wave to the speaker you could trace the signal path to see where the distortion was being introduced and narrow down the problem component(s).
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    10baseT Hub

    The CAT ratings show what data rates the cables will support and what the longest distance for those rates.  Wikipedia has some good information.
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    10baseT Hub

    If the same cables worked with the 1 Gb hub, then it is unlikely it is the cables, unless by making the change to the other hub you corrected a broken wire.  Ports do go bad on hubs and switches.  Did you try other ports on the 10 Mb hub?  It is also possible that due to the age of the 10 Mb...
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