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All replies
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Helpful answers
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May 23, 2014 4:42 PM in response to anticlimaticby BDAqua,Hi,
Some mostly older startup keys, but yes, I think you should at least see a question mark, do you have the Disk Tools Floppy?
Apple Boot Key Combos:
Bypass startup drive and boot from external (or CD).... CMD-OPT-SHIFT-DELETE
Boot from CD (Most late model Apples) ................. C
Boot from a specific SCSI ID #.(#=SCSI ID number)...... CMD-OPT-SHIFT-DELETE-#
Zap PRAM .............................................. CMD-OPT-P-R
Disable Extensions .................................... SHIFT
Rebuild Desktop ....................................... CMD-OPT
Close finder windows.(hold just before finder starts).. OPT
Boot with Virtual Memory off........................... CMD
Trigger extension manager at boot-up................... SPACE
Force Quadra av machines to use TV as a monitor........ CMD-OPT-T-V
Boot from ROM (Mac Classic only)....................... CMD-OPT-X-O
Force PowerBooks to reset the screen................... R
Force an AV monitor to be recognized as one............ CMD-OPT-A-V
Eject Boot Floppy...................................... Hold Down Mouse Button
Select volume to start from............................ OPT
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May 23, 2014 7:56 PM in response to BDAquaby anticlimatic,Thank you for responding.
I do have a disk tools floppy, and have tried all of the possible key combinations, but the hang-up seems to occur before the machine looks for that input. I know these models typically don't boot past a black screen if the PRAM battery is dead, so I'm wondering why a new battery doesn't affect it. Which part contains the boot settings that the PRAM powers, is it the hard drive, or logic board?
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May 24, 2014 3:23 AM in response to anticlimaticby Jan Hedlund,Yes, as BDAqua indicated, you should at least see a floppy icon with a flashing question-mark.
The computer will search for a valid startup disk in the floppy drive first.
If you suspect that the hard drive is faulty (and thus somehow is blocking the computer), you could simply remove it and boot from a floppy for a test. However, there are other things to check. Begin by disconnecting and reconnecting cables. Reseat memory modules. Finally, examine the logic board (use a magnifying glass). Look for cracked/discoloured/bulging/leaking electrolytic capacitors (as well as other damaged electronic components) and bad solder joints. Of course, do not do anything inside unless the computer has been switched off and disconnected from the mains.
Jan
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May 24, 2014 12:32 PM in response to Jan Hedlundby anticlimatic,Thank you for your response.
After looking at the logic board I found one cap that had a good amount of black residue around the base of it, near the power supply. I left the machine running overnight to see if I could warm it up, and sure enough the computer booted the hard drive with no problems. Does thisfurther point to the caps being the issue? I have never recapped a board before, and unless I miss my mark those are "blind" surface connectors. How does one get solder between them and the board? What is a good solution to use to clean it?
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May 25, 2014 3:59 AM in response to anticlimaticby Jan Hedlund,>I left the machine running overnight to see if I could warm it up, and sure enough the computer booted the hard drive with no problems. Does thisfurther point to the caps being the issue?
Electrolytic capacitors (that have not been in use for a while) may be "reconditioned" to a certain degree. So, yes, the described behaviour appears to indicate that there is a capacitor issue.
>I have never recapped a board before, and unless I miss my mark those are "blind" surface connectors.
There are two types of SMD (surface mount device) electrolytic capacitors. One is a barrel variant on a base plate, the other is a rectangular (often yellow) type. It is also possible that you will find normal barrel types with axial or radial leads.
>How does one get solder between them and the board?
If you wish to try replacing capacitors, much information about techniques can be found on the Internet. There are special tools for SMD. However, with access to one or two suitable standard soldering irons, desoldering braids, a desoldering pump and solder wire, you should be able to handle it. Wear safety glasses!
>What is a good solution to use to clean it?
Special equipment and cleaning liquids are available. Also, one can sometimes read about people using a household dishwasher (only with water) to clean circuit boards.
Jan
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May 25, 2014 11:40 AM in response to anticlimaticby Appaloosa mac man,For what it is worth, just because the old capacitor was surface mount does not mean that the replacement must be surface mount. Then you do not have an issue with inserting solder between the board and the component.
Another technique we have used on older machines is to totally disassemble and reassemble the component parts. Connections may have oxidation issues. Reseating RAM, unplugging wires and reconnecting them. Look for foreign objects like loose screws and paperclips.
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May 25, 2014 5:47 PM in response to anticlimaticby Jeff,"After looking at the logic board I found one cap that had a good amount of black residue around the base of it... I left the machine running overnight to see if I could warm it up..."
Are you sure that it wasn't just accumulated dust? It's possible that what you observed is coincidental and not causal, as to the boot problems you've been having. Perhaps the problem is within the power supply? I'd want to rule that out, before removing/installing a capacitor.