Macintosh Classic Color does not turn on

[habibrobert]

Hello everyone,

I am trying to get a Macintosh Classic Color to turn on. I am using a keyboard that once belonged to a Macintosh Power 5400. I used the on button on the keyboard but nothing happened (there shouldnt be a compatibility issue with the keyboards....right?)

Anyways I'm wanting to open it up and see whats going on inside. Any good way to go about this? Do you need any special scree drivers? I've seen some extra long screw drivers on ebay for the classic compact mac cases. I'm not sure if the same thing applies to a Color Classic?

My next question is discharging the monitor. Can anyone post a link for the tool that you use to discharge the monitors (sorry I dont know the name!). Also, I've been told you can hook up the ground to a the metal frame of the computer. However, I have also been told that you have to be careful on where on the metal fram you attach the ground to because it could fry the board. Can someone tell me exactly where to put the ground wire?

I'm just scared of frying the board, maybe it would be better to attach the ground to something other than the metal frame? Or does that not work? I don't want to shock myself in the process!

Any Advice on what could be wrong would be much appreciated!

Warmest Wishes,

Habib

 

[JRL]

No special screwdrivers needed - you should just be able to unscrew two screws at the back and open the lid. You can slide out the motherboard from there.

Make sure you press the Power button on the KB after you flick the switch on the back first. Kinda obvious suggestion, but it can be easy to forget. Also check the caps on the motherboard for leakage - #1 culprit right there.

 

[habibrobert]

Thanks for your reply! You mean I can slip out the motherboard without disconnecting it from the monitor? I read in another posting that it is kind of tricky to disconnect the motherboard from the monitor because it involves talking the yolk out which can be very delicate. Did I read that correctly? Or am I mistaken?

 

[JRL]

Nope, the monitor isn't connected to the motherboard in that way. You just need to pull carefully on the motherboard outwards.

I would still strongly recommend replacing the caps. Even if they ultimately don't end up being the problem they're going to be at or beyond their serviceable life anyways. You might be understandably nervous to do it but if you're careful the process isn't that bad.

 

[habibrobert]

Thanks for the advice. There is some serious leakage here. Looks like a pram battery exploded at some point. What do you guys like to go with? Tantalum, or aluminum caps? Also, I see that there are 3 slots for inserting some type of ram, two shorter ones and one long one. The large slot is empty, but the two little slots are filled. I'm assuming the larger slot is supposed to be filled with some sort of ram?

 

[JRL]

First clean up the PRAM battery residue with a qtip and alcohol and check if there's any damage to traces or chips.

It's a personal choice, really. Many people go for tantalums because they last longer, but some people like the aluminum electrolytics because of their stock look. The larger slot is for VRAM but since the CC has onboard VRAM you don't need anything in the slot.

 

[habibrobert]

I will give that a shot. Just out of curiosity, what would happen if the traces are damaged? Does that make the board useless?

With regards to tantalums vs. stock caps. Some people on this forum say that you never really know how a capacitor that was not designed to be on the board will function, therefore it is best to go with the stock caps. Is that taking things a little too far? Or have people actually experienced this? After all, a capacitor that is rated the same as the old one should work....right? It would be bad if capacitors were that unpredictable, but I'm not electrical engineer, so who knows... Any input would be great.

Also, I've heard of many people dishwashing their boards. Do you guys reccomend that? Also, do you have to unsolder the old caps do to this? Or does it not matter since the caps are bad anyways?

Thanks!

 

[JRL]

You can fix corroded traces by soldering a small wire (I use small wires stripped from IDE hard drive cables) in place of where the traces would normally run. You can test if a trace is electrically broken with a multimeter.

That fear really is baseless. The tantalum caps are superior to the aluminum electrolytics in almost every way hence why they are slightly more expensive. Just make sure you have the same capacitance and exact (or slightly greater) voltage replacements.

You can put the boards in the dishwasher if you want; you just have to be careful if you do so because if you don't dry it out well you can accidentally corrode your board. Hence why I just clean with a qtip or toothbrush and rubbing alcohol.

 

[habibrobert]

Thank you so much for your advice. I will give all of this a shot and let you know what I come up with.

 

[habibrobert]

Photos of the carnage I found!

 

[Macdrone]

Pretty standard carnage at this point. Doesn't look horrible, most SE/30's I've seen look way worse.

 

[JRL]

Thankfully it isn't too bad. Just try to clean it up the best you can with the alcohol.

 

[techknight]

Hopefully itll work fine after its cleaned up. But with battery acid its hard to say.

 

[uniserver]

Pram battery removal

 

[habibrobert]

I washed the motherboard yesterday and tried turning on the unit today. Much to my surprise it turned on! However, it just showed a blank gray screen. Guess I'm going to have to send this to Uniserver to get recapped. Thanks for the advice guys!