Common issues with Apple Macintosh Systems - Part 2 : PRAM Batteries
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- Опубліковано 9 лип 2016
- Welcome to Jason's Macintosh Museum!
This video is all about batteries - specifically, the Parameter RAM (PRAM) batteries that live inside every Apple Macintosh system.
There were three main types of PRAM battery that Apple used on their Macintosh systems:
1984 - 1987 : A21PX (AA size, 4.5V Alkaline)
1987 - mid 2000s : (1/2 AA size, 3.6V Lithium)
1994 - 1998 : (4.5V Alkaline, plastic case with leads)
If any of these are left inside a system for an extended period of time, these batteries can start to leak, and the battery acid can corrode the logic board, rendering it useless. Therefore, you should never leave the PRAM batteries inside any system unless you have one of the specific systems that need one to boot.
For example, the Macintosh II, IIx and IIfx all need two working PRAM batteries to boot, so that the power supply control circuitry on the logic board can function and start up the main power supply unit.
Some other systems (such as the LC 475), require a PRAM battery to be present in order for the system to boot and initialise the video.
I personally have several systems that have been rendered useless by leaking batteries (IIfx, PowerMac 8100, PowerBook 190), and I hope this video will clearly show the risks involved in leaving a PRAM battery inside an old Apple Macintosh system. - Наука та технологія
Ah, you're back! good to see you here again Jason.
Thanks so much for this channel Jason!
Glad you are back!
JMM is the best UA-cam channel, there's no doubt about that.
I love your videos Jason. Thank you!
Great video Jason! Keep it up your good work, upload videos twice a week!
Thank you do much; I've just gt a M5000 mac II in pristine condition that deosnt start, and one of the battery is dead, now I know why it doesn't start" thanks so much for archiving this!
Thanks mate. Great presentation. I have a Macintosh Power PC 5200. It’s been sitting around for 15 years! I booted it up and got a floppy disk symbol with a question mark. I’ll try remove the PRAM battery. Wish me luck!
The 386 and 486 pc motherboards had a soldered on Nicad barrel battery that were prone to leaking when not in use for a while.
Great information. Thanks for sharing!
When are you going to be making more walk through of the other older Macs?
Great advice, thank you so much!
What a good channel! I subscribe immediately! Thanks for making these videos. I have a question for you: What happens if I install an alkaline battery instead of a lithium battery? Thanks for your attention.
Also, would you consider doing a video on some of the peripherals for the early Apple line such as external floppy drives, CD-ROM drives (such as the AppleCD SC), scanners (such as the original Apple Scanner), external hard disks (such as the 20SC) and printers (such as the Image Writer I & II)?
Thanks for this video. It scared me into looking at my old Macintosh LC (circa 1990-1992) I received in 1998. I haven't turned it on since at least 2004...and unfortunately it is not powering on now. No sound, no video, nothing. I'm going to have to open it up to check that the battery is okay but I have the feeling that it leaked and things got corroded unless there's another thing that could have gone wrong with it. This is a good PSA for anyone that has a older/vintage computer, especially a Mac. I had stored my Mac because it is a sort of prized possession of mine (my first computer and obviously an older one) and because I knew it might gain value over time should I wish to sell it in the future - I tried to take as good care of it as I knew how ever since I first got it 18 years ago. I had wanted to turn it on recently but nothing happens, much to my disappointment. Anyway, if anyone has an older computer of any kind, keep this video in mind and take the battery out of your computer, especially if it's working now.
Zachnorn You need to replace the Battery.Had the same Problem wit my iMac G3.Replaced the battery and boom,it powerd on again.
Also capacitors in the power supply leak, and on the motherboard.
When you use AA batteries in the machines I recommend using Energizer Ultimate lithium batteries since they should pretty much never leak, and they are now rated with a 20 year shelf life so they have very low self discharge.
Back in the late nineties I bought a Performa 575 for my gf, and we found out that it needs the battery (purple barrel you show) for it to run. Manny years later I also found out that the mini g4 also needs a battery (coin) to run.
I have a AA battery in my Plus, and it works like a normal PRAM battery. Although I'm worried that it could do damage since it's not an actual PRAM battery
ahhhh the bloopers at the end were great, haha. Reminds me of what I say to myself making my vids, haha.
I enjoyed the full video as well.
Hi Jason ... fascinating, and thanks for sharing. I own a mid-80s Macintosh II, with a second hard drive, updated with a super-drive, and I believe additional memory. This computer has a board (maybe 3” x 3”) that sits on the large logic board with a capacitor and two Maxell 1/2AA batteries in the center of the motherboard. One battery was beginning to expand so I replaced them both. I am trying to restore it. It is in pristine condition. The PRAM info is clearly gone since the last time this was powered on was probably 1990-ish. I was able to power it on, the drives spun up, no chime, no video. I can’t find a website for you, and would like to get it going again. Do I need a boot diskette? Will command+option+P+R reset the PRAM (I don’t know when that feature came to be)? Any advice would be greatly appreciated.
any way of soldering on pram battery sockets on an Apple IIgs, Mac II, Mac SE, etc.
These Maxell 1/2 AA are certainly little devils. I picked up two Macintosh IIfx some time ago, and the mainboard of one of these has been utterly eaten away by one of the Maxells inside, including the battery holder.
Hi.. Is there any source of information on how to remove the PRAM battery in all the old Macs?
37:04 , "90 apple mark 012o" is a bipolar 8pin IC. I suppose, this chip has 1.25v voltage reference and comparator for checking battery voltage. I designed in 1992 Sony.
Please make a Video about The Powerbook 5300 Series
Hi Jason, I dont know how active you are with comments on legacy videos but thought you may be interested to know about the "Inorganic Lithium Battery". Its made by Sonnenschein GMBH which are now a division of Exide.
At least the 40MHz 68030 and FPU in that IIfx seem to be intact...did you save them?
Hi Jason, love your videos. I was wondering if you could please upload a video on how to transfer original software from a modern PC (in my case Windows) to an 800k disk for my Mac Plus? Info on the net is sketchy at best for this process. Thanks :-)
Just a follow up since posting my question, I found a neat little device called the "Floppy Emu" and am considering purchasing it www.bigmessowires.com/shop/product/floppy-emu-deluxe-bundle/
My IIci the Maxell battery in it vented and sprayed something corrosive all over the bottom of the floppy drive and whatever vapor let off also go in the hard drive and corroded it internally too, completely wrecking the system.
Just took the batteries out of my PowerBook G3 (Bronze Keyboard). Both were looking a tad sketchy.
Have you tried removing the acid with vinegar?
Hello Jason, I have a Macintosh II dated 1987, I found it abbandoned in the house of my father...I am fond of its because it was my first computer.
I tryed to power on, but no sign of life has arrived to me...
Batteries are solded on the motherboard and, luckily, none of them has leaked acid. I tested with a multimeter one of them still reports 3.3V, but the other one reports -0.5V.
Do you think that this condition could prevent Mac to power on? Or I have search the problem elsewhere (power supplier perhaps?). Thank you in advance, and compliments for your videos! Andrea
LOL Why did you say you are ashamed that there is a IIfx board in the II? My II just arrived last Friday, and I was ecstatic when I found that it had the IIfx board/processor in it! :) It won't fire up though, and I have a sneaky suspicion that it may be batteries instead of the power supply if I'm lucky!
Would this cause the screen to show a floppy disc with a question mark on it on boot up?
I had a maxwell in my G4 Cube that leaked. I thought it exploded by how it looked. But luckily I think it was left on its side for years while it went. The tadiran brand I have in my G3 and G4 tower and they have been fine since I last looked. I recently got an iMac G3 600 snow with a saft battery in what read 0.02v so it was a good time to save and replace. Hoping this is stopping the system from working as the bored measured voltage from what I’ve seen online to test but only clicks on and straight off
I’ve also encounter “newer” intel motherboards (not even Apple ones) not work without a CMOS battery so hoping putting one in my iMac G3 will help it. 5v trickle power is there and starting it goes to 20v but clicks straight off so hopefully I can find the issue if it’s not the PRAM battery
Hi. I have upgraded my 2017 22.5 iMac ( 32 GB and SSD 1TB) but the computer does not start. I was checking the green LEDS that confirm when powered and start are green but the third one ( GPU) does not light. So the problem is in the GPU?. If I change the PRAM battery the problem can be fixed? Thank you
My very first compact Mac had a horrible case of battery leakage. I was very disappointed but have since acquired a working compact Mac with one of the blue batteries. Needless to say I removed it.
Are you in England or the US? I've got an entire collection of classic Macs going back to a IIvx and a Classic II around Phoenix, Arizona that I can't continue to store, can't repair, and don't want to throw in the garbage.
I’ll take em off your hands
My guess is that the maxcell lithium batteries would be more prone to leaking, due the very large protruding postive terminal, Those Lithium batteries, are Lithium Thionyl Chloride chemistry, Lithium thionyl chloride batteries use a glass to metal seal to isolate the positive terminal from the negative terminal/case of the battery. That large nub on the positive terminal seems like it could very easily be levered against the internal glass seal and break it.
On the 475 if you flip the power on off real quick after the chime it will boot.
Nice video. I hate battery leakage
This was a huge problem when I got a Macintosh IIfx
My 5300 had it battery contacts eaten away. Batteries are now just to fill the bay.
Nice video Jason and first
My IIgs has a batterty from 1990 that has not leaked.
It will. It's only a matter of time.
I know therefore I changed it to a new one. Interesting thing is that some batteries last very long, some very short. could that be depending on the usage of the machine, or is it the quality of the battery? It's a risky thing, because the new batteries could possibly be much worse that the old ones.
Jason, if you'd like to send the unrepairable to me I can take a further look at doing some micro surgery on the boards for you.
Ahhhh, the Maxell "mini-bomb" Have seen these actually explode......
i had a maxell like that in a imac g3 at least it didn't leak
I'd like to make your own captions instead of using generated captions.
So what you are saying is that the 🔋 is a ticking time bomb. Got it.
i just leave the pram batteries out
3rd
You shouldn't drop down into your chair like that.
leaking batteries - destroyer of apple/homecomputer/pc-worlds :
the bomb aka maxxell batteries have destroyed many macs, SAFT batteries seem to be better
The Tadiran brand batteries seem to hold up signficantly better than the Maxells. Hope the SE/30 I ordered has a Tadiran.
my powermac 6100 had a tadrian battery, it was dead so i swapped it with another tadrian from a imac g3 then it died later so i just left the battery slot empty. my lime 333 imac had a maxell battery.