-first of all, I'm an idiot with a scope since i have never used one... but I'm trying my best here " -

If you didn't recondition the analog board, stop until that's done. Save yourself a lot of ghost-chasing.

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Thanks for the input but to me that does not make sense to me. To be sure I tried the Se/30 LoBo in my known working SE which gave me the same result.

Since the PSU outputs normal voltages needed for the floppy drive, I have no video problems whatsoever, and it does not make a difference with the hdd in the machine or in an extermal enclosure with it's own PSU I would not expect the analog board for this to be the problem.

But I found something very interesting today, let's call it a minor success!

I borrowed a digital multimeter-device from a friend of mine, that also has an oscilloscope with the output shown on a pc via software. It's slow - as expected - and annoying to use, but it does kinda give me the impression of what was going on. Results are in:

The floppy transmits and receives data from/to the SWIM, you see every pin actually do that on the scope.

Here is the amazing part: as soon as i kept the probe between ground and pin 4 of UH7, the WR-line, the disk started formatting as if NOTHING was wrong.

Hey Ike,~Did you check everything around UH7 (especially pin 4 and 16 to swim /floppy connector). Also check the pins on UH7 that go to the GLUE chip (page 3 of the SE/30 schematics that can be found on net) because that's responsible for inverting that WR line...if any of those are faulty could be a prob.

Finally did you check around L22 inductor/C67 cap and R30 resistor (around SWIM and floppy connector) as they are all part of the WR line...long shot though!

~

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So this was kind of the right answer... the issue I have with my situation now is: The continuity checks just fine!

Why does prodding around with my scope solve the problem temporarily?