Mac Classic in Trouble... Bad ROM? Need Help...

[mac_mike]

Greetings everyone! I've been meaning to post here for awhile, but I've delayed it hoping that my old, previously reliable Mac Classic edition might fix itself to no avail. Basically, the mac boots up, and all I get is the grey desktop background... nothing happens after that. The hard drive spins, but nothing happens. The screen looks fine, but there is no mouse pointer or anything else. Sometimes, if I tap on the little tab buttons on the left side of the case near the back, I will get the sad mac logo with an error code of 000001. It is my understanding that is the code for a bad ROM. Since I can't replicate the sad mac all the time, maybe there is more than that. This malfunction occurred all of a sudden with no previous signs or hints of trouble. What do you guys think may be going on?

I have purchased the long torx screwdriver to open the machine, but I've been stalling. I'm no stranger to soldering and working with electronics, but the whole, "CRT capacitors have enough voltage charge to kill you," is a little unnerving. The machine hasn't been switched on in months, so it's probably OK, but still give me some pause. Any safety tips? I've heard of putting the logic board in the dishwasher, which also seems crazy, but apparently it works.

As a long shot option. I also have in my possession the chassis to an old Mac Classic II (which I believe is a color version).  I know the parts and boards are different, but I was wondering if it might be possible to simply replace the Mac Classic chassis with the Classic II? I know it's probably unlikely, since they are different machines and one is color and the other isn't, but if that might be an option that would be an incredibly easy potential fix. Any chance this might be possible?

Based on my research, I should try to start by opening the case and reseating the ROM. Does that sound right? Anything else I should try (besides looking for capacitor leakage)? Any help, advice, or assistance would be greatly appreciated! Thank you so much in advance for your expertise and help! 

 

[bibilit]

The Classic and Classic II are both Black and White, and boards can be swapped.

Only the Colour Classic is different.

Your problem is probably related to capacitors, or bourne filter.

 

[techknight]

Macs will do this if it cant talk to certain peripherals or if there is an IRQ stuck. on the portable, the SWIM does this when it goes bad. But who knows on the classic. 

Reason why bourns filters cause this on systems like the SE/30 and such is because it holds the chip in a state where when the mac attempts to initialize its hanging around waiting for it. 

 

[Scott Squires]

Even if the capacitors aren't the problem this time, you're going to have to replace them sooner than later, so you should get comfortable opening that Classic. Really, you should be replacing them now so that they don't damage the logic board traces more than they already have. You should have respect for the CRT, but it's not so terrifying that you shouldn't open the machine up. The high voltage areas are well insulated and if you're careful then you're not going to touch them on accident. Just don't touch the red suction cup and avoid the analog board. Avoid the CRT neck because it is fragile. The power supply circuit on the Classic is exposed (at least on my Classic it is), and I don't know enough about power supplies to know if it's dangerous, so I stay away from there. You don't need to go near any of these areas to work on the digital parts of a Classic.

The primary thing is to take special care when disconnecting the power connector to the logic board. Those mini fit jr. connectors tend to get stuck and require a lot of force then come loose suddenly. The way it is positioned, you can snap the neck of the CRT if you pull the connector off with great force. Remove it slowly and the hardest part is over. Yours might not even be a tight fit.

From there it's a very simple matter to slide out the logic board. Take it apart and you'll see.

 

[techknight]

Well if that thing isnt recapped, then all bets are off. on everything... The classic is the worst of the compact mac series as far as caps are concerned because the analog board is just as bad as the logic board. the SE/30 runs a close 2nd because its usually just the logic board. 

 

[mac_mike]

Thank you all so much for your input!! It looks like this is going to be a big mess of a job, unfortunately.   I guess I can start by dishwashing the logic board? That sees so scary to me, but since the unit isn't working, I guess I have nothing to lose.  The swapping of the logic boards isn't going to work like i thought. Apparently, the extra chassis I have isn't from a classic at all, but from a performa from many years later. 

Thank you again for your responses! I really, really appreciate it!!   I will keep you informed as to my progress.

 

[mac_mike]

BTW, what do you think of a service like this? http://www.ebay.com/itm/Macintosh-Classic-Re-Cap-Service-/182409567339?hash=item2a78751c6b:g:YpEAAOSw2s1UxY2j  

They do all the recapping and cleaning for ya! That would certainly save a lot of time and aggravation for me, although if the analog board is bad, too... well, that would stink for sure!

 

[EvilCapitalist]

That's someone who used to be a member here.  He does excellent work, as many folks on here (myself included) can attest and if soldering isn't in your wheelhouse using him would be a smart plan.

 

[mac_mike]

Thank you all for your advice! I opened my mac and found that not only had the capacitors leaked, but the battery did too... badly... very corroded, so that explains the problem. By remarkable luck, I saw posted on eBay a recapped Classic Board for a great price, so I grabbed it and installed it today. It started up, and I even got sound (which I hadn't had from the main speaker in a long, long time). so that was great, but then I got the "Question Mark" Floppy icon which suggested a bad hard drive; however, the hard drive sounded normal... it was making reading and writing sounds like it normally would, so I'm a big confused. I booted up the mac into system 6.0.3 in ROM using the Command + Option + X + O trick (which took a few tries to actually work) and it doesn't find the hard drive at all--it doesn't exist to the mac. I've had hard drives go bad before, and they make an awful sound when they do. Did I not press the connector in hard enough (or too hard perhaps, I pushed it in there pretty good)? I don't think I put it in the wrong way... Could the board be bad? What do you think is the most likely problem, what should I do next, and if it's user error (like the cable the wrong way), did I break something for good? I tried a mac floppy disk, and that did work ok thank goodness!!

Thank you for all your assistance, it is greatly appreciated!!!

 

[dochilli]

I own about 20 compact Macs and 50 % of them had defect harddisks. So this in not unusual... Buy a SCSI2SD. This is a great replacement for old harddisks.