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White Bars: Macintosh Classic II

MrCheeto

MrCheeto

Suspended
Original poster
Nov 2, 2008
3,531
353
Was working on a Macintosh Classic II, then the client allowed me to keep it for myself.

He informed me that the Mac had a checkerboard pattern on startup, so they replaced all of the caps. (They just happen to manufacture logic boards) Afterward, it shows four white vertical lines, no chime.

I've washed the electrolytic fluid from the board and need to reseat the components. Everywhere I look online, the boards in Classic II's are not similar to mine because the ROM chips appear different. Most have four small ones, while mine has two large ones.

Can somebody confirm that this is just a typical Classic II motherboard?
bf52343d.jpg


Also, which of these two ROM chips is properly seated? There is an extra pair of pins in both sockets, so I'm not sure how to insert them.

61b50012.jpg


I demand answers! [Please]
 
Last edited by a moderator:
So I was told time and time again how this exact issue was solved 99% of the time by washing the electrolytic fluid from the board...nada.

I still have four solid white bars across the screen and no chime.

The caps where professionally replaced so...what now?
 
I installed the ROM's correctly, then.

I did not install a battery since this one is useless anyway and using a dead battery is worse than using no battery.

So it's been washed, the ROM's are indeed seated correctly...
 
iDecker said:
I installed the ROM's correctly, then.

I did not install a battery since this one is useless anyway and using a dead battery is worse than using no battery.

So it's been washed, the ROM's are indeed seated correctly...
Click to expand...

Hmmm, check continuity from the shoulders of the ROM pins, to the pins on the underside (solder side) of the ROM sockets.

Other than that, it's anybody's guess.

I'd also be checking (which may require removing the caps) that the radial electrolytic caps' pins aren't shorting tracks underneath and that no tracks have been etched thru.

Buying another logic board is an option, but it would probably be in the same poor condition that this board originally was.
 
What would a perfectly-functioning Classic II do if you attempted to boot it with no RAM?

Are there any other motherboards that are less prone to such issues that I may fit inside here?
 
iDecker said:
What would a perfectly-functioning Classic II do if you attempted to boot it with no RAM?

Are there any other motherboards that are less prone to such issues that I may fit inside here?
Click to expand...

Classic II has 2MB soldered RAM, so it should at least boot.

There's nothing that will directly fit the Classic II chassis that doesn't suffer from leaking SMD caps.

Perhaps the only early Mac that doesn't even use SMD caps, is the Quadra 700.
 
The 5v and 12v pins on the molex connector to the motherboard are reading about 0.2v off.

Would this possibly be an issue?
 
Eliminates that...

The other thing I noticed is that it will do exactly the same thing with no motherboard installed! Meaning, the motherboard could be entirely dead and there's be no way to tell ><
 
iDecker said:
Eliminates that...

The other thing I noticed is that it will do exactly the same thing with no motherboard installed! Meaning, the motherboard could be entirely dead and there's be no way to tell ><
Click to expand...

Hmmm.... does sound like it might be an etched track or even a corroded pin on an IC or an IC's solder.

Etched tracks are fixable with prototyping wire (and other methods) but it's not the most enviable task. I've done it heaps of times, and it's a pleasure when it works, but when that last track eludes you it's frustrating as... well.. you know. :mad:
 
-.-

I'm going to let it bathe for the next hour. Tomorrow will decide the fate of this project. A restore, or Mac Mini mod...

*sigh*

Almost just as well. I always wanted an SE/30 anyway.
 
iDecker said:
-.-

I'm going to let it bathe for the next hour. Tomorrow will decide the fate of this project. A restore, or Mac Mini mod...

*sigh*

Almost just as well. I always wanted an SE/30 anyway.
Click to expand...

SE/30's are just as bad for leaking SMD caps. :(

Have a look around the replaced caps. If you see any black on the tracks, plate-thru holes, or IC pins, that's possibly where the trouble is. Of course, an IC could be fried internally, but electrolyte corrosion is more likely.
 
Yes, but if I find a restored SE/30 with newer caps, I'd at least have a toy for a good amount of time :)
 
o.o

128MB of... RAM??? What??? Who would ever even use that much? Like, are we launching space ships and tracking satellites at the same time here??? Ridiculous. Typical Apple.
 
Check the pins on the CPU for cracking/solder issues. I had a few powerbooks that needed the CPUs resoldered (I did 5 603e's by hand :O), otherwise I'd just get a whole bunch of crap on the screen. Try heating the board up with a hairdryer to test if it's the CPU, it's not 100% accurate, but it'll tell you that something's not soldered correctly.
 
Heat it? I'm sorry, but at what point would I know if it's been heated properly? What exactly am I trying to accomplish with the heat?
 
iDecker said:
Heat it? I'm sorry, but at what point would I know if it's been heated properly? What exactly am I trying to accomplish with the heat?
Click to expand...

Just heat it, as hot as the hair dryer can make it. You just want to temporarily test if there are any cracked solder joints. The heat from the hairdryer should be just enough to expand the solder/pin to reconnect until they cool down again. If the trick works, you'll basically have an idea that something needs to be resoldered, and if it doesn't work, then chances are the solder joints are ok. Usually you should heat up and test one IC at a time, starting with the CPU, then the ASIC, etc...

Worked for my G5 with bad solder joints on the RAM slots. The heat from the hairdryer was enough to establish a good connection on the broken RAM slot solder joint, so I knew I had to resolder the ram slot. 1920 pins resoldered, and the G5 is up and running again :D
 
Basically baked the thing with a heat gun and tried to start it fifty-times in about ten-minutes...no dice.

*sigh* feelsbadbro
 
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