Busted? - Macintosh SE/30 Board Repair - Part 1

[@adriansdigitalbasement]

Great stuff Joe! That’s one messed up board!

[@JoesComputerMuseum]

Thanks. Wait until you see the next one. Its even worse!

[@gordonlachlan4144]

a trick : you can watch series on Flixzone. I've been using them for watching lots of of movies these days.

[@johnmartin9294]

@Gordon Lachlan yea, I've been using flixzone} for years myself =)

[@ARCJavMaster]

As always, amazing video! This will help troubleshooting the oncoming SE/30 board I just purchased.

[@JoesComputerMuseum]

;)

[@JVHShack]

Hey, Joe! Thanks to you making a certain video a few years ago, I got to play with my Apple IIGS. It's a shame that nobody subs to your channel. One note about this video: the very last part seems like it's slightly out of sync between audio and video. I just have a nasty ability to detect that. Keep up the really cool work!

[@JoesComputerMuseum]

Thanks for letting me know, and I'm glad you like my work!

[@aaronjamt]

Was the “Floating” Point Unit causing “floating” data lines?

[@geekwithsocialskills]

I recently revived a Mac SE/30 board that was pretty messed up like the one you got as well. I put the board in my sonic cleaner for a while which helped clean it up, then began the process of running many bodge wires. If you need some high capacity RAM for it, let me know and I would be happy to send a donation to you/your channel, just send me a direct message (contact details on my about page). P.S. nice to see you using the Mac ROM-inator II Atom SIMM from Big Mess o' Wires. Lots of cool Apple stuff on that site!

[@JoesComputerMuseum]

Hey, thanks for the message! Hopefully, I won't need bodges, but time will tell.

[@SteveRieck-Music]

Awesome video! Sunscribed. Thanks.

[@trevgauntletneu_gaming]

I have a question regarding diodes D1 & D2. What did you use to replace them?

[@JoesComputerMuseum]

In this case, standard 1N1418.

[@craigchamberlain]

I'm repairing a battery-bombed SE/30 just now and I suspect I might also have FPU issues because I can boot 6.0.3 but not 6.0.5, 6.0.8 or 7.5.5 beyond a certain point. With 6.0.5 it asked me to name my computer and then stopped accessing the disk (SCSI2SD) with the watch icon on screen. With 6.0.8 it boots to what looks like a blank desktop with blank menu bar and active mouse pointer. And with 7.5.5 it gives the Welcome To Macintosh screen then starts the progress bar on the next screen but only gets about 15% of the way. I guess my next move is to inspect the FPU for broken traces or bridges/gunk before doing your little trick with the chip select line. Does anyone know why we see this behaviour with pre-6.0.5? Was the FPU not utilised by the system generally before 6.0.5 perhaps? Maybe only used for specialist apps? I'll report back on progress.

[@JoesComputerMuseum]

Hey! Yeah, certain versions of classic Mac OS used the FPU and others didn't, but I didn't do an exhaustive check during my diagnostics. Like with all things, this problem could be the FPU or could be just about anything else. From a 10,000 foot view, it smells to me like a problem with the RTC, crystal, etc. in the battery bombed area. Like the OS tries to read the PRAM and can't, so it gives up. Also explains why the one version of the OS was asking for the computer name.

[@craigchamberlain]

@@JoesComputerMuseum Thanks for the reply - yeah that's a good suggestion as I did need to rebuild the area around the RTC with new D1 and D2 diodes and a new crystal. I've just received an ATX PSU extension cable today so should be able to debug more easily with the logic board out of the chassis. Will check if the RTC is signalling or not. On that subject, any tips on selecting an Oscilloscope? I threw out my old CRT based digital oscilloscope during my recent house move and have been tempted to pick up a Rigol scope for projects like this. Any tips on what features to look for when balancing cost and feature set? I'm an electronics engineer so I understand the fundamentals but would appreciate your feedback on these. Thanks.

[@JoesComputerMuseum]

@@craigchamberlain On an o-scope: I'm no expert. For most of what we're doing, the simplest quality scope will work. You need at least two channels, 50mhz bandwidth and you'll probably be just fine. Heck, even an old in-good-condition CRT scope will work.

[@craigchamberlain]

@@JoesComputerMuseum thanks, yeah I think something like a DS1054z is probably plenty capable for working on anything from the 1980s and probably the 1990s too! Thanks.

[@retropuffer2986]

I just love those vintage macs! I always used System 6 since System 7 put a big load on the regular Plus/SE machines. But with that 030...... :D

[@JoesComputerMuseum]

This thing is going to be my classic Mac go-to, that's for sure.

[@JulienMR]

Do you know where to find the "Sony" IC pairs? I mean the 2 Audio chips retagged by Apple: mines are corroded, and I need to change them...

[@JoesComputerMuseum]

I do not. I have been looking myself for a couple of years now.

[@JulienMR]

​@@JoesComputerMuseumthanks for your answer. I think it might be some common chips, relabeled, but I have no idea what they can be...

[@lemonherb1]

Instead of removing the FPU, I wonder if you couldn't just use an ethernet card that usually has an FPU socket on board. It plugs into the PDS slot of the SE/30 as well as other cards. Normally the FPU socket is vacant as some Macs had a working FPU soldered on the logicboard which will be the opposite of your situation now

[@JoesComputerMuseum]

Good idea!

[@AmigaofRochester]

I just fixed a SE/30 someone man handled. Got it booting and display! Got another one the bench as we speak.

[@JoesComputerMuseum]

SWEET

[@piratestation69]

I still say those old macs are paper weights... never used one and never will. Ill take an apple //e any day... but anyone that can restore a piece of history kudos.