Macintosh SE failing to POST

- The computer had memory issues at the beginning (corrosion) so I tried downgrading from 4MB to 2MB (changing the jumper as well of course) and ...

The first would be the hard drive. The Quantum SCSI drives the old macs use are incredibly prone to failure. If it does fail on you (it's bound ...

Probably not the latter if the FDD is only 800kB, but how do you know that there is an HDD? Do you hear it?

I've seen this mentioned before, as LIDO not working with the Mac Plus and only working with the SE FDHD and later. But... I have no idea what ...

Do you hear the hard disk spin up? (I can't remember if the SE FDHD has a fan or not... if so, it would be a separate motor noise from the fan).

Second issue was the gummed up floppy drive. I fully disassembled it and cleaned (did not disassemble the heads, I basically detached the ...

I've acquired this beautiful Macintosh SE and it's in need of help. Will I be able to make it work? Part 2: https://youtu.be/siR-XEheM90 ...

In that case, it may not like the boot disk and kept starting from hard disk, giving you the same error. Do you have a 880k or HD floppy drive ...

This Macintosh SE is in need of some TLC. After removing the RIFA caps, it's time to fix the hard drive and try out some SCSI drive ...

With the Mac SE's hard drive promptly failing after installing System 6.0. ... Through a stroke of luck (or possibly pity), a random post ...

Macky-Mac said: ack, not good.....what did you do to the machine after the first post? other than cussing at it? whatever it was, I hope it ...

I am not a Mac expert but it sure sounds likely you have a hard disc problem. Do you have a boot floppy you use to start up? Mac SE, that is ...

This can be either some faulty trace (have you checked the batteries?), a bad socketed chip, or a 'dead' chip. First step is checking for ...

Sometimes is related to the RAM, so my first try would be to remove all the SIMMs and test it with known working RAM. If not, just install what ...

be/dl6pi7J_ALI I have this old Macintosh SE which has developed a mouse issue ... post-458217 ADB chip adaptor: https://tinkerdifferent.com ...

But unfortunately again the SE/30 does not want to boot from that floppy disk. I am still a bit confused as the floppy drive used to work really ...

the sad mac along with the error code. I am unable to find the ... Albert Einstein will be eternally grateful. Preview my answer. Post my answer ...

could possibily be the source of the -199 error. Thus getting the files to the Mac SE without using floppies or floppy drives could bypass any ...

This is by far one of your most revolutionary videos for Mac II/SE diagnostics thus far. Kudos to you Adrian for this investigation!

In early September I published a post on Mastodon, with what was meant to be a humorous comment. “Oh no”, I said, implying that there is ...