Thread
Can dead battery cause hard disk trouble?
I have a :lc: (Performa 475).
It had a dead PRAM battery, so I had wired it up to a voltage regulator that I had built, powered from a transformer. I then changed that to a similar regulator, but mounted internally powered from a PP3 battery so I could use it with the case cover on
.
This is what happened:
Day 1-Mains powered regulator installed, boots fine three or four times that day
Day 2-Battery powered regulator installed, boots fine two or three times
Day 3-Trouble (see explanation below) booting
Day 4+Same trouble experianced
A week or so later-Will not boot, regulator voltage checked and found to be too low
The perpetual problem is, when booting, the hard disk does strange things. Every second time I boot it, it spins up, then, about ten seconds later when it should start booting, it spins down again and shows me a flashy floppy picture. There is no grating or scraping from the hard disk, and it boots from a floppy OK. When it does boot from the hard disk, it works fine.
I then discovered the "double-flick" thing. I tried that, and now, every time, it does "problem". I haven't since tried it with a regulator/battery, so I don't know if that works, but again it does boot from a floppy.
My question is, would getting a new PRAM battery fix the problem. I say this particularly because the problem only showed up after a while (battery voltage dropping over time).
P.S. Don't say my hard disk's bad, because I haven't got another!
It had a dead PRAM battery, so I had wired it up to a voltage regulator that I had built, powered from a transformer. I then changed that to a similar regulator, but mounted internally powered from a PP3 battery so I could use it with the case cover on
.This is what happened:
Day 1-Mains powered regulator installed, boots fine three or four times that day
Day 2-Battery powered regulator installed, boots fine two or three times
Day 3-Trouble (see explanation below) booting
Day 4+Same trouble experianced
A week or so later-Will not boot, regulator voltage checked and found to be too low
The perpetual problem is, when booting, the hard disk does strange things. Every second time I boot it, it spins up, then, about ten seconds later when it should start booting, it spins down again and shows me a flashy floppy picture. There is no grating or scraping from the hard disk, and it boots from a floppy OK. When it does boot from the hard disk, it works fine.
I then discovered the "double-flick" thing. I tried that, and now, every time, it does "problem". I haven't since tried it with a regulator/battery, so I don't know if that works, but again it does boot from a floppy.
My question is, would getting a new PRAM battery fix the problem. I say this particularly because the problem only showed up after a while (battery voltage dropping over time).
P.S. Don't say my hard disk's bad, because I haven't got another!
I just do not understand peoples irrational fear of PRAM batteries - it's almost become an epidemic!
The reason PRAM batteries (and any other type of battery of that type) explode, leak, cause damage etc is because they're OLD! It's not because the batteries within themselves are inherently dangerous. Almost every piece of electronic equipment that uses these type of batteries all advise that if you do not intend using the device for any length of time to remove the batteries. That seems a pretty good piece of advice to me and it applies equally to old computers as it does to any other piece of electronic equipment. Yet so few people seem to bother follow this simple piece of advice - and are then surprised when damage occurs.
To solve your problem - replace the PRAM battery with one of a similar type. Most of the PRAM batteries used in Macintoshes are Lithium 1/2 AA 3.6v - these are easily obtained on places like eBay for a couple of bucks. Save yourself a lot of time, trouble and messing about and replace the PRAM battery and remove it if you don't intend using the machine for any length of time AND replace it once it's gone beyond its useful shelf life.
Simple!
The reason PRAM batteries (and any other type of battery of that type) explode, leak, cause damage etc is because they're OLD! It's not because the batteries within themselves are inherently dangerous. Almost every piece of electronic equipment that uses these type of batteries all advise that if you do not intend using the device for any length of time to remove the batteries. That seems a pretty good piece of advice to me and it applies equally to old computers as it does to any other piece of electronic equipment. Yet so few people seem to bother follow this simple piece of advice - and are then surprised when damage occurs.
To solve your problem - replace the PRAM battery with one of a similar type. Most of the PRAM batteries used in Macintoshes are Lithium 1/2 AA 3.6v - these are easily obtained on places like eBay for a couple of bucks. Save yourself a lot of time, trouble and messing about and replace the PRAM battery and remove it if you don't intend using the machine for any length of time AND replace it once it's gone beyond its useful shelf life.
Simple!
I know I could replace the battery, I was just wanting to know if that would fix it before I waste my money/time. I have no fear of PRAM batteries, just wanted to know if that would solve it.
Keep posting!
Keep posting!
I meant to say that I would like to know why it won't boot with a double flick, as I have heard that that works, and I wouldn't have to buy a battery :lol: .
You need to try and understand why the voltage is dropping.
In my opinion from what you're written, the Hard Disk isn't getting sufficient power from the board to continue working and that's why it's spinning down.
From the limited information you've given, if the voltage is dropping and there is insufficient power to keep the HD spinning, you may have bad capacitors, because that's a typical symptom of bad caps.
That's just a stab in the dark from the information you've given - it could be a lot of other things as well.
In my opinion from what you're written, the Hard Disk isn't getting sufficient power from the board to continue working and that's why it's spinning down.
From the limited information you've given, if the voltage is dropping and there is insufficient power to keep the HD spinning, you may have bad capacitors, because that's a typical symptom of bad caps.
That's just a stab in the dark from the information you've given - it could be a lot of other things as well.
Um... the voltage drop is from the regulator that pretends it's a battery. That's not what powers the hard disk is it?
I can't really give much information as I'm a newbie to old macs.
I can't really give much information as I'm a newbie to old macs.
If it starts to boot, the PRAM battery is unlikely to be your problem.
It looks like you have a faulty PSU or that something in your 475 is sucking up a lot of power on boot. Have you tried booting from floppy disk?
Edit: Isolate the problem. Fit a new PRAM battery.
It looks like you have a faulty PSU or that something in your 475 is sucking up a lot of power on boot. Have you tried booting from floppy disk?
Edit: Isolate the problem. Fit a new PRAM battery.
Yep, already advised that!
You can speculate and theorise till the cows come home, at the end of the day you have to start proving or disproving some of these theories and you can't do that if you have 'unknowns' in the mix.
It may well be a faulty PSU, but variable and inconsistent startups are often due to the board capacitors not holding any or little charge and that sucks power out of the board causing inconsistency. You won't know that of course until....you replace the PRAM battery!
Full circle!
I'm pretty sure it is the PRAM "battery", as it was when I used the battery-powered regulator for it that trouble was starting, and it was only when that ran down that the mac's hard drive caused trouble every time.
Now, when I do the double-flick thing to start it, the hard drive never works properly. I have read in Wikipedia that the double-flick works on this very model. My question is, why does it never work (the mac boots from a floppy and the video does start up, but the hard drive doesn't work).
Finally, I have included a detail of each kind of startup my mac goes through (I have not timed this accurately).
Successful:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive starts clicking
15 sec-happy mac, "Welcome to Macintosh"
17 sec-extensions start loading
25 or 30 sec-main desktop appears and mac is now usable
Unsuccessful:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive spins down
15 sec-blank grey screen with moveable cursor
17 sec-floppy disk with flashing "?"
Unsuccessful with bootable floppy:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive spins down
15 sec-happy mac, "Welcome to Macintosh"
About a minute later-main desktop appears, mac is usable, but hard drive is not present on desktop and is not recognised by "disk first aid" or any other programs on the utility disk
Double-flick:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-hard drive spins down
6 sec-power switch off (sometimes I do this before hard drive spins down at 5 sec)
7 sec-power switch on again, follow unsuccessful startup from 0 sec
I know this is rather long, and I know I could replace the PRAM battery, but I just want to know why it won't boot when I do the double-flick thing and if there's anything I can do about this
.
The startups are not inconsistent. I have read about people who say it their mac starts up "about every third time, although today it started up twice with no trouble". I did at the time find it strange that my mac always started up fine every second time, with the alternate time causing the exact same trouble every time. It never deviated from this pattern, even when I had left it for days. I even did a cold restart and it did it again :lol: !
Now, when I do the double-flick thing to start it, the hard drive never works properly. I have read in Wikipedia that the double-flick works on this very model. My question is, why does it never work (the mac boots from a floppy and the video does start up, but the hard drive doesn't work).
Finally, I have included a detail of each kind of startup my mac goes through (I have not timed this accurately).
Successful:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive starts clicking
15 sec-happy mac, "Welcome to Macintosh"
17 sec-extensions start loading
25 or 30 sec-main desktop appears and mac is now usable
Unsuccessful:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive spins down
15 sec-blank grey screen with moveable cursor
17 sec-floppy disk with flashing "?"
Unsuccessful with bootable floppy:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-breif hard drive and fan dip as video starts up, normal fan/hard drive sound restored
13 sec-hard drive spins down
15 sec-happy mac, "Welcome to Macintosh"
About a minute later-main desktop appears, mac is usable, but hard drive is not present on desktop and is not recognised by "disk first aid" or any other programs on the utility disk
Double-flick:
0 sec-power switch flicked, fan and hard drive spin up
2 sec-startup chime
5 sec-hard drive spins down
6 sec-power switch off (sometimes I do this before hard drive spins down at 5 sec)
7 sec-power switch on again, follow unsuccessful startup from 0 sec
I know this is rather long, and I know I could replace the PRAM battery, but I just want to know why it won't boot when I do the double-flick thing and if there's anything I can do about this
.
UPDATE:
This morning I tried to boot my mac again. I was actually trying to test a system 6 boot disk that I have been trying to make for a while.
I tried it 3 times with a floppy. Each time, it booted as for a double flick startup, then it proceeded to read the disk. Then, I got this:
xx(
00000F
000001
The second time it booted, I think I briefly saw a :b&w: , but I'm not sure.
On the third try, my hard disk started clicking. That's one time in about 8-10 times sice trouble struck. I couldn't see if it would mount it, however, because I had my bad boot disk in the floppy drive, so insted I got the sad mac. I then, of course, tried it without the floppy, but the hard disk did is usual thing.
I'm not sure what the codes mean, and there was no chord sequence, but I don't suspect the sad mac to be a hardware fault, as it did not happen when I tried it without the floppy.
This is just an update, much help would be appreciated, as it is still not working properly.
P.S. If you could help me make my boot disk, that would be helpful too
This morning I tried to boot my mac again. I was actually trying to test a system 6 boot disk that I have been trying to make for a while.
I tried it 3 times with a floppy. Each time, it booted as for a double flick startup, then it proceeded to read the disk. Then, I got this:
xx(
00000F
000001
The second time it booted, I think I briefly saw a :b&w: , but I'm not sure.
On the third try, my hard disk started clicking. That's one time in about 8-10 times sice trouble struck. I couldn't see if it would mount it, however, because I had my bad boot disk in the floppy drive, so insted I got the sad mac. I then, of course, tried it without the floppy, but the hard disk did is usual thing.
I'm not sure what the codes mean, and there was no chord sequence, but I don't suspect the sad mac to be a hardware fault, as it did not happen when I tried it without the floppy.
This is just an update, much help would be appreciated, as it is still not working properly.
P.S. If you could help me make my boot disk, that would be helpful too
onlyonemac asked:
Given that you only own one Mac, you are asking for trouble by experimenting in this way. Sooner or later, the hard disk will stop booting.
Quick-flick on the power switch is a diagnostic method for identifying whether a Mac might work before replacing the PRAM battery. Having verified that the Mac works, sane people replace the PRAM battery.
Every time that you boot the Mac and it gets as far as looking at the hard disk, the Mac logs the fact (on the disk) that it tried to boot. With System 7.5 (?), Mac OS looks at the log and if there are failed boots, it flags the disk for repair. Boot will be slower.
Given that you only own one Mac, you are asking for trouble by experimenting in this way. Sooner or later, the hard disk will stop booting.
Quick-flick on the power switch is a diagnostic method for identifying whether a Mac might work before replacing the PRAM battery. Having verified that the Mac works, sane people replace the PRAM battery.
I have heard that people use this on this very model all the time!
The thing is, yes, it can be done, and it can be used as a long term "fix", however given the extra wear and tear you're putting on the machine...there's no real point in it when you can avoid it by spending all of $7 on a battery.
When a hard drive starts spinning up and down at power on, there are 2x obvious reason.
Either the heads are stuck in the parked position and repeated attempts free them.
Other possibility is that the PSU is not giving enough power, probably due to failing capacitors.
Given the age, both the logic board and the PSU need to be recapped.
I don't think that a new pram battery will be enough to solve your problem.
Either the heads are stuck in the parked position and repeated attempts free them.
Other possibility is that the PSU is not giving enough power, probably due to failing capacitors.
Given the age, both the logic board and the PSU need to be recapped.
I don't think that a new pram battery will be enough to solve your problem.
I thought the same this morning
.Earlier today, I connected another voltage regulator to the battery slot. This one was powered from a small transformer, but had a power jack on it so that it could be mounted internally.
Startup was the same as with an unsuccessful startup from the list above. I tried it three times with the same result.
I don't think that it needs recapping, as there are no signs of cap crap on the mother board. I have tried reseating the hard drive power and SCSI connectors with no change.
Anymore suggestions? :?: :?: :?:
P.S. I don't have time/money to spend on recapping/PSU change/new hard drive, but please suggest anything other than those standard and overmentioned fixes.
:'( :'( :'( :'( :'( :'(
The "overmentioned fixes" are the only solution. Electrolyte Capacitors degrade over time: that's just basic chemistry. Leakage is not always obvious, they can also dry out or don't leak at all while they are bad. You need an ESR meter for testing capacitors.
Since your performa 475 is at least 16 years old, it's likely failing capacitors that cause the problem.
You may not like my answer but these "standard" fixes do solve the problem in 90% of cases like yours.
I have rebuild my IIsi PSU a while ago, it's 3 years older than your performa 475, but the PSU was a mess inside with many leaking capacitors.
Also you are looking at the logic board: the problem is most likely the power supply.
If you don't want to go this way and spend money to keep your computers in working condition then I would suggest looking for another hobby...
Sorry,
Nico
I can't really even check the capacitor's in the PSU, as I am inexperianced enough with mains voltage circuits. If you can help me there, please feel free to do so. Maybe once I've finished my own PSU project I'll be more confident.
Speaking of other PSUs, is there any way that I can try my computer with a different supply (I don't know about the power connector pin mapping either). If that works, I might want to try recapping my PSU, otherwise I won't bother with that.
P.S. Old macs is not my hobby-I was just given an unloved mac.
Speaking of other PSUs, is there any way that I can try my computer with a different supply (I don't know about the power connector pin mapping either). If that works, I might want to try recapping my PSU, otherwise I won't bother with that.
P.S. Old macs is not my hobby-I was just given an unloved mac.
UPDATE:
I have measured the voltage coming from the PSU. These are my results:
Under no load:
-Blue wire: -4.8v
-Yellow wire: 11.11v
-Orange wire: 5.27v
There is also a tick about twice a second-it seemed to speed up as the supply was running for a while.
Under load when powering mac:
-Blue wire: -5.06v
-Yellow: 12.3v
-Orange: 5.1v
The tick is not present when the supply is under load (I disconnected the fan and hard drive so I could hear if there was a noise)
In both cases, my meter has a 1M ohm impedance.
I have measured the voltage coming from the PSU. These are my results:
Under no load:
-Blue wire: -4.8v
-Yellow wire: 11.11v
-Orange wire: 5.27v
There is also a tick about twice a second-it seemed to speed up as the supply was running for a while.
Under load when powering mac:
-Blue wire: -5.06v
-Yellow: 12.3v
-Orange: 5.1v
The tick is not present when the supply is under load (I disconnected the fan and hard drive so I could hear if there was a noise)
In both cases, my meter has a 1M ohm impedance.
Recap it.
You're about the 3rd or 4th person to say exactly the same thing, the symptoms the machine is showing are typical of failing capacitors.
If the OP is not prepared to spend any money on purchasing a replacement PRAM battery, somehow I doubt he's going to invest any time, money or effort in replacing the board capacitors.
Those figures look okay, but it's through the logic board where it's losing voltage and that's probably being caused by failing capacitors.
There's a couple of other things you could try -
1/ Plug the HD into a good known PSU (not the Mac PSU) and see if that spins the HD up sufficiently to boot. Obviously you'll need to have the HD data cable connected to the Mac logic board.
2/ Heat up the board with a hairdryer and see if you can get the capacitors sufficiently warm to enable at least one successful boot.
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Umm... I don't know the correct voltages for each pin on the connecter. Help appreciated. Also, the HD spins up initially, the problem is it won't stay spun up long enough for the mac to boot from it (see boot timelines posted above in previous posts).
How does warmming the capacitors help???
There are capacitors inside the power supply. When they go bad, the power supply dies with "the click of death". Your power supply is "clicking". Replace the capacitors inside of it. I feel like several people are repeating themselves in this thread.
Capacitors don't have to show any outward signs of failure to have either failed or be failing. In many ways electrolyte leakage, exploding tops etc are extreme examples of failure - they're by no means the 'norm'. Most of these capacitors have 1,000 hour MTBF's and maximum operating temperatures of 85 degrees, which shortens their life. If you want to know more about this subject, this site is very informative - http://www.badcaps.net/.
Please don't think that just because there's no signs of failure, that they haven't failed or aren't failing.
Look up the make and model number on google and find out what the power requirements are.
It brings them up to their usual operating temperature and can often coax them into working long enough for you to boot the machine. This is not a 'fix' it's a diagnostic method to help identify if your capacitors are failing. If they work when warmed up and won't when cold then you have your answer.
Umm... my mac always made an atticy smell when in use. I thought nothing of it-it always had that sort of smell, even when not in use. That was the smell of the person who gave it to me, so I thought. I did notice that it smelt more when running, but I just put it down to "the smell comes out more when it's warm".badcaps.net said:
I would not say that it stank, but that could be a sign. Maybe PSU capacitors aren't as smelly
.
UPDATE:
Yesterday I tried booting my mac again. It had nothing to do with the battery/hard disk/PSU/capacitor problems-I was testing a boot floppy. I was using the double-flick to boot the mac.
I, as has already been mentioned, was trying to make a system 6 boot floppy (see post 15 June). I never managed to make that disk, but I did make a system 8 floppy which booted fine.
I did, however, notice something interisting with the hard disk. Once, it did stay spun up, but I was in the process of zapping the PRAM, so of course the mac rebooted and the hard drive didn't work. Why does the drive spin once and then not again? I didn't disconnect the power, switch the mac off, change a thing, but yet the second it wouldn't go. On the times, however, when it did eventually spin down (the "bad" startups), I heard a faint rapid "click click click click" noise from the disk, about twice a second. I don't think, however, that that's a sign of stuck heads, as it was running fine 5 seconds before.
Yesterday I tried booting my mac again. It had nothing to do with the battery/hard disk/PSU/capacitor problems-I was testing a boot floppy. I was using the double-flick to boot the mac.
I, as has already been mentioned, was trying to make a system 6 boot floppy (see post 15 June). I never managed to make that disk, but I did make a system 8 floppy which booted fine.
I did, however, notice something interisting with the hard disk. Once, it did stay spun up, but I was in the process of zapping the PRAM, so of course the mac rebooted and the hard drive didn't work. Why does the drive spin once and then not again? I didn't disconnect the power, switch the mac off, change a thing, but yet the second it wouldn't go. On the times, however, when it did eventually spin down (the "bad" startups), I heard a faint rapid "click click click click" noise from the disk, about twice a second. I don't think, however, that that's a sign of stuck heads, as it was running fine 5 seconds before.
The hard disk doesn't have a model number printed on it (I just took the cover off the disk, but none of the disk platters said anything on then :lol: :lol: :lol: ). Seriously now, it just says "Apple 3.5 internal HDD", or something like that. I did notice, however, that the power requirements on the disk stated 5 and 12 volts dc. Which wire is which voltage, however, and is there an easy way to find out?
PSU states 5v, 12v and -5v on sticker. Those voltages look so far out to me that I think it'll damge my logic board with that over-voltage :O !
UPDATE:
Today I've tried more to fix the mac.
Firstly, I checked the voltage and current going to the drive. The currents are as expected, but the voltages are not. The 5V supply is fine, but, at the point where the drive shuts down, the 12V supply begins to rise (strange as the main PSU doesn't even supply more). If, however, I measure it under no load, it stays at 12V (i.e. it's not rising because of the current drop). Strangly, the drive continues to draw from the 5V supply even when it has stopped.
Secondly, I discovered a very strange thing. When starting up, the speaker emits a very quiet whistling noise, a bit like a jet plane. At first, it rises, then it wobbles a bit in pitch, then, at the point when the drive would have shut down (although the noise is there even without the drive), it starts to slowly lower in pitch, but seems to always remain present.
Are the two issues related or not? And what is causing the 12V supply to rise in voltage?
Please help; don't abandon my topic .
Today I've tried more to fix the mac.
Firstly, I checked the voltage and current going to the drive. The currents are as expected, but the voltages are not. The 5V supply is fine, but, at the point where the drive shuts down, the 12V supply begins to rise (strange as the main PSU doesn't even supply more). If, however, I measure it under no load, it stays at 12V (i.e. it's not rising because of the current drop). Strangly, the drive continues to draw from the 5V supply even when it has stopped.
Secondly, I discovered a very strange thing. When starting up, the speaker emits a very quiet whistling noise, a bit like a jet plane. At first, it rises, then it wobbles a bit in pitch, then, at the point when the drive would have shut down (although the noise is there even without the drive), it starts to slowly lower in pitch, but seems to always remain present.
Are the two issues related or not? And what is causing the 12V supply to rise in voltage?
Please help; don't abandon my topic
.Sorry, the 12V supply does not rise, but stays steady when the current drops. It was a fault with my meter (it does that sometimes). I would have done this as an edit, but for some reason there was no edit button.
why haven't you supplied the main board with 3.6v's? sometimes i come across over sized 3.6v pram batteries i just solder wires to the +/- and then just a dab of goop and stick the battery in another place on the main board.
first things first, get voltage to the pram, if you had other macs i would suggest trying another hard drive, i'm thinking the hard drive is bad, witch is totally common, these scsi drives are old and going bad all the time.
also, try to get more then one mac, then you are enabling some trial and error, with out spare parts you cant do much.
but then you might have to change your user name
first things first, get voltage to the pram, if you had other macs i would suggest trying another hard drive, i'm thinking the hard drive is bad, witch is totally common, these scsi drives are old and going bad all the time.
also, try to get more then one mac, then you are enabling some trial and error, with out spare parts you cant do much.
but then you might have to change your user name
How can it be a bad hard drive when he can't get it to boot off floppy either? Is the floppy drive bad too? It's possible, but highly unlikely.
The most likely scenario is, (and it's been mentioned countless times and is well documented on this forum) is that the capacitors on the logic board have or are in the process of failing. If the capacitors are indeed in the process of failing, then they will not be able to filter the dc current running through the logic board and that is precisely the reason the hard disk will not spin up - it's not getting sufficient power.
The voltage outputs from the PSU look okay, the reason it's still not booting is because those voltages are getting lost on the logic board due to likely failing capacitors. Replacing the PSU won't make any difference, neither will replacing the hard disk.
I accept the OP doesn't want to accept this as the reason, but there is no other logical explanation as far as I can see.