the rom and IWM chips look fine the sockets are clean. I can try reflowing some of those rusted joints.
Mac SE no bong, no display. not getting anywhere with troubleshooting
- Thread starter marcocet
- Start date
Nothing seems to happen when i press it.
The reset button shows 450 ohm not pressed and 0 when press so seems to be working?
The Interrupt shows 3750 ohm when not pressed in though? Is 450 for the reset button too low?
also interupt button may be broken as it doesnt change resistance when pressed
13.5V is high - not sure exactly what would cause that (power supply issue?). Usually the problem is the opposite with voltage too low. I think most (maybe all) of the chips would run off 5V.
At this point, it really could be anything wrong with the logic board.
May be worth taking a close look with a magnifying glass on backside to see if there are any broken solder joints, and on the component side to look for broken or corroded traces or components.
After that, I'd go through the diagnostics in a systematic way. For example, follow the algorithms for "dead sets" in the Larry Pina repair books.
Good luck!
Yea im not sure why it is that high. I didnt think it was that high when i measured previously
Yea I will do that and look closer for traces
Oh interesting i didnt realize there were books other than dead mac scrolls. I will take a look at the dead sets section!
Thank you !
Yeah you could also check out: https://vintageapple.org/macbooks/pdf/Macintosh_Repair_&_Upgrade_Secrets_1990.pdf
and https://archive.org/details/macclassicse00larr
Yea sorry I meant I would check that out. I didn't realize the author had more books other than dead mac scrolls.
Hey been a little while. I never had much luck looking for problems physically on the board, but I ended up getting a Zoyi ZT-703S starter scope for some other projects and hopefully it will be helpful here. I tried to measure the output of the oscillator crystal and output is shown in the attached video. Im unsure if this is an issue with the board or if im doing something wrong.
View attachment IMG_0463.MOV
This doesn't seem right.
View attachment IMG_0463.MOV
This doesn't seem right.
Alright well im getting the same reading from the crystal on my mac plus which is fully functional so. Not sure whats going on there
I dont seem to be getting anything on the CLK pin on the cpu so maybe that could be it?
In looking at your logic board pictures on the first page, that's some serious oxidation/rust.
It would be a good idea to soak the board in vinegar, or use an ultrasonic cleaner with detergent specifically for electronics, to stop that corrosion.
The pictures appear to show broken traces on the top and the bottom of the board and possibly rotted capacitors but it's hard to tell without a continuity check, or from just a picture.
The only schematic I found for the SE was here:
oldcrap.org
-And they are fuzzy looking .gif files.
I'm not much help but contributing what I can. Can only recommend to use a magnifying glass/headset to spot what looks like dark spots interrupting the green traces on the chip legs, or caps, and then verify the traces with a meter.
It would be a good idea to soak the board in vinegar, or use an ultrasonic cleaner with detergent specifically for electronics, to stop that corrosion.
The pictures appear to show broken traces on the top and the bottom of the board and possibly rotted capacitors but it's hard to tell without a continuity check, or from just a picture.
The only schematic I found for the SE was here:
apple-mac-all-schematics-68k - Old Crap Vintage Computing
Apple Macintosh - Apple and Bomarc schematics for Portable, Plus, SE, SE30, Classic, II, IIci, IIcx, IIfx, IIsi, LC II, LC III, Quadra 840av.
oldcrap.org
I'm not much help but contributing what I can. Can only recommend to use a magnifying glass/headset to spot what looks like dark spots interrupting the green traces on the chip legs, or caps, and then verify the traces with a meter.
Attachments
Yea there is a decent amount near the I/O. I was hoping the machine would still work sense its just I/O traces.In looking at your logic board pictures on the first page, that's some serious oxidation/rust.
It would be a good idea to soak the board in vinegar, or use an ultrasonic cleaner with detergent specifically for electronics, to stop that corrosion.
The pictures appear to show broken traces on the top and the bottom of the board and possibly rotted capacitors but it's hard to tell without a continuity check, or from just a picture.
The only schematic I found for the SE was here:
-And they are fuzzy looking .gif files.apple-mac-all-schematics-68k - Old Crap Vintage Computing
Apple Macintosh - Apple and Bomarc schematics for Portable, Plus, SE, SE30, Classic, II, IIci, IIcx, IIfx, IIsi, LC II, LC III, Quadra 840av.
I'm not much help but contributing what I can. Can only recommend to use a magnifying glass/headset to spot what looks like dark spots interrupting the green traces on the chip legs, or caps, and then verify the traces with a meter.
I washed the board with soap and water but yea I can do that.
Where do you see the broken traces and bad caps?
Yea same schematics I found, they are quite bad unfortunately. I did find a SE logic board recreation project though. Assuming it has the same layout it could be helpful? But unsure if its exactly the same. https://archive.org/details/macintosh-se-reloaded-master
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