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SE/30 : Simasi (bad capacitors?)

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I have installed a quantum 2-gig internal drive. All was well with formating, installing system software, etc. I was on my way to installing netBSD when after a reboot, I got the simasi mac. In reading on line (http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html#SimasiMac) this link suggests cleaning the RAM and ROM connections, removing the network card from the PDS slot, and changing the PRAM battery, which I did, all to no avail. So I'm pretty convinced that one of the capacitors has gone bad. I'm more than willing to do this myself, but have no idea about soldering/desoldering. Does anyone know of someone who will look at the logic board for a reasonable price? Or any suggestions for replacing the capacitors myself?

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Before going for a capacitor replacement, have a look at the board and try to find any signs of capacitor leakage (it will look like Cola spilled on the board). If there is any, clean it off with some alcohol and cotton buds/Q tips or alternatively remove the battery and SIMMs and stick the motherboard in the dishwasher. Seriously! If you're not keen on the dishwasher then it could also be cleaned using water in a bowl. If going for any cleaning involving water, ensure that the board is fully dry before trying it out. In my experience this often cures the Simasimac problem, for how long is anyone's guess.

 

Given that your SE/30 was working properly recently I would hazard a guess that any capacitor problems have not reached a serious enough level for full on replacement yet. If, however, cleaning the board does not work then there are some threads on these forums detailing capacitor replacement services (use forum search).

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To be blunt, once you enter leaking capacitor territory the question is not whether but how soon to replace them. As insurance, while you are 'inside', as it were, inspect also and resolder the analogue board connections mentioned in the plethora of posts about SE/30s in these Forums. The practice on the gross-scale joints of the analogue board will prepare you for the fine-scale work on the logic board.

 

de

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Before going for a capacitor replacement, have a look at the board and try to find any signs of capacitor leakage...

I address the myth of visually spotting leaked capacitor fluid in this post.

 

And since my "sticky request" was declined in a previous thread on capacitor replacement, here is the link to that.

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I'd put it this way: If you see leakage, you definitely have a problem. If you don't see leakage, you may still have a problem.

 

Given how common this problem is, it's generally safe to assume that replacing the capacitors is necessary when you see simasimac or other characteristic symptoms. Sure, reseat simms and all that -- it's worth a go, but in the end, most folks end up having to replace the caps.

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Certainly cleaning is a good "quick fix" but I agree it won't last for ever. Fortunately in my case I found another much better SE/30 so the one with capacitor issues has been mothballed for the time being.

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I know this isn't going to be what you want to hear, as it certainly wasn't something I wanted to face up to when I first started playing with SE/30's, but the cold hard fact is that all SE/30 logic boards now need to have their capacitors replaced. Those silver SMD tank capactors are notorious for leaking, but even your big axial caps may have leaked as well through the years.

 

Your "much better SE/30" may serve you in a satisfactory manner for a few months if you add nothing to it hardware-wise, but you still may get a random crash now and not know why. You may think it's an extension or software conflict when it very well could be an iffy capacitor. Capacitors are designed on your logic board for a reason, not simply to act as filters, but often used to "stabilize" current flow throughout the board. If something becomes unstable on the logic board, it can show up in the form of a system crash or the dreaded horizontal lines at cold boot.

 

But once you start adding RAM or HD's or PDS cards to that "much better SE/30" you will then start to see more clear signs that the caps need replacement. My remarks on this topic are not merely guesses by me or assumptions based on theoretical failure analysis of electrolytic capacitors. I speak of things I've experienced first hand myself. I wish we didn't have to replace those silly caps, but we unfortunately need to. Simply cleaning the board doesn't put leaked fluid back into the capacitors (i.e., it won't restore their original capacity to hold a charge).

 

But once you get past the capacitor problems, the fun begins. The SE/30 is a great classic Mac to work and play with.

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