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Finally got this little 512K Mac put back together with a couple of interesting new faults along the way. Just in time for the last day of #MARCHintosh! Special thanks to the community here in the 68kmla forums and shoutout to @tashtari for the excellent TashTwenty project and @reallyrandy...

Thanks for all the tips, I was able to get this booting but the results seem a bit unstable. I now have the following settings in my zuluscsi.ini, `EnableSelLatch` seemed to have no real effect. [SCSI] Debug = 1 # Same effect as DIPSW2, enables verbose log messages SelectionDelay = 0 #...

Tried with the Siliverlining image and still no attempt to boot and booting from floppy there are no additional drives on the desktop. Using the 6.0.8 Image as HD0.hda and the Silverlining as HD1.hda. No difference if only using HD0.hda or renaming HD0 to HD6.hda etc.. [0ms] Platform: ZuluSCSI...

Just tried by connecting the micro-usb power and the result is the same. The red LED blinks once at power up, and then blinks every second or so at the question mark screen. Trying different images and sometimes there are no blinks at the question screen, but always the single blink at power...

It's the ZuluSCSI Mini that only has the DB-25 connector. I am plugging it straight into the back of the Mac Plus.

Howdy, hope this is simple! I have a ZuluSCSI mini and can't seem to get it to do anything. Trying various image files and zuluscsi.ini changes always results in the question floppy screen. Booting from a floppy containing 6.0.8 and I don't see any additional drives show on the desktop. Can...

Update! -- IT FREAKING WORKS!! What a journey, even though this post didn't get much love, thanks for inspiring me all the same. Seeing the posts here definitely kept me going back to this project with new ideas. So what did I try, well, everything. But with all major chips socketed and known...

https://windswepthomeblog.files.wordpress.com/2021/09/plus_analog.pdf This document has some of the sections like Vertical Sweep covered. Looks like Q1 and Q2 according to the schematic are the main drive transistors for the vertical sweep.

Pic of the socketed 512K board so far. Ignore the wires attached to the CPU, this was to test a Rominator that is similarly not working with thus board.

Okay a bit of an update, really hoping someone knows what this means. First, because I am impatient waiting for the replacement 6522 I have socketed the LAG and BMU0 PAL chips. After socketing and reinserting the chips I got the checkerboard pattern. This seems to indicate that the video...

Looks like the horizontal drive is working properly and the max potential of the vertical drive is way below spec. Have replacing any of the transistors affected the display in any way? I would focus on the vertical drive portion, could be crazy but resistors and diodes can fail. Worth probing...

Does anyone have a Macintosh 128K or 512K logic board, in any condition that they would be willing to part with? I have been slowly socketing the various chips on my 512K board and inserted one of the PAL chips backwards :'( I put way too much time into this and now I think its dead forever..

A little bit of further progress, While waiting for the replacement 6522 VIA to arrive I have socketed the 8530, adjacent 4016, and IWM chip. With the 8530 removed the behavior is the same. Speaker pops with RAM fully populated, sad mac with one RAM chip removed. With the IWM removed the...

Some progress maybe, I socketed the 6522 VIA and the adjacent 3440042 CLK chip. With the CLK chip removed the results are the same with or without removing a ram chip. However, with the VIA removed the mac goes straight to a black screen with no speaker pops. With a RAM chip removed and the...

Some videos that may help ROM and RAM replaced, Gray Screen, Speaker pops, no Sad Mac. When any RAM chips are removed, Sad Mac Based on this article: https://macgui.com/news/article.php?t=496 It seems the failure occurs when its done with all ROM and RAM tests and starts this stage...

Howdy 68kmla'rs! I was given a Macintosh 512K that was in very rough shape. As is common, the battery had leaked and the whole chassis was covered in rust. Phase 1 The computer actually showed signs of life even in this rough shape. After wiggling the cable between the logic board and analog...