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Figuring out dead PowerMac 6100

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This one has stumped me. It has the symptoms of a broken CPU but I've got two boards and they both don't LOOK broken. I've also got two power supplies, two ROM SIMMS, multiple RAM sticks. None of these parts mixed together produces a working 6100... When power is applied the power light comes on, PS fan spins up, I see the keyboard LEDs blink but then absolutely nothing else happens. No chime, no video, no evidence that it's trying to boot off HD or floppy. Tried with a good PRAM battery and doing the on-off-on trick.

 

What am I missing here? I don't see caps leaking but even with caps going bad I suspect the machine would still show some life. Pretty sure the thing worked before I stored it so I have no idea.

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Likely caps still. All of these should be re-capped immediately. In the process of refurbishing my fleet, I won't even attempt to power them on without re-capping first (lest I cause damage). I'd start there and then see how it works out.

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They are on the tip of needing them. If you figure, given that we are at 2019 practically, that would make the oldest Power Macs roughly 25 years old or so. None of my classic Macs from the 1980s needed anything 10-ish years ago, and now they all need some work. Time sneaks up on you like that.

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Ive ran into a Power Mac 8100 and even an 8500 that needed capacitors replaced on the logic board in order for them to boot, before they had no chime and a blank screen, ive heard of 6100s needing logic board and PSU caps replaced as well.

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OK well I'm feeling a little better about my situation then. I don't mind doing the recapping so long as it may help fix my problem and I'm not just wasting time on a dead board. I'll order up the caps I need for the job and try this within the next couple of months I guess.

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Also make sure you're running with an actual ROM, not a cache card. If you have a proper ROM and a cache card installed, try removing the cache card. I've had a few cache cards go bad and prevent the Mac from booting.

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On 12/31/2018 at 7:59 AM, AwkwardPotato said:

Dang. I guess I should look into recapping my 6100. :-/

For sure.  I recently recapped a 6100 where the caps were literally falling off the board at the slightest touch.  The thing is it worked fine a year ago.

I also have an 8100 and I checked the caps on that board and they are not showing any signs of leakage or corrosion as the solder joints are still shiny.  I will still recap it within this year though, just to be safe.  

 

Those were made in 1994 so next up would be my 7200 or 640CD, although neither of those show any leakage or even a hint of corrosion.

Edited by Zippy Zapp

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All the PowerMac x100 machines are nearing the age of capacitor failure. I’d say at the moment most will probably run fine, but definitely the first wave of dead caps has arrived for them. Another few years and I think we will be at the point where a majority of them will be needing new caps.

 

And so time marches on :)

 

If that doesn’t work let us know and we can go from there.

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21 hours ago, Franklinstein said:

Also make sure you're running with an actual ROM, not a cache card. If you have a proper ROM and a cache card installed, try removing the cache card. I've had a few cache cards go bad and prevent the Mac from booting.

 

Yeah I've got two ROM cards and one cache card, already tried running it without the cache card.

 

I'll be trying the board recap first and see what happens.

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do you have a good battery?  If not the 6100 needs a power button double tap.  Turn on, turn off then turn on again.  6100 will need caps but should work, but a bad battery will require a double tap to boot.

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Second the battery advice.   The 6100 is one of the few models that doesn't power on properly with a flat battery.

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On 2/5/2019 at 8:03 AM, Macdrone said:

do you have a good battery?  If not the 6100 needs a power button double tap.  Turn on, turn off then turn on again.  6100 will need caps but should work, but a bad battery will require a double tap to boot.

Yeah I tried a new battery from a small stash I ordered last year and didn't make any change. Also tried the double tap method. I haven't gotten around to the recapping yet but I'll try that first and hopefully it solves my problem. 

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