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Elvi
February 6th, 2012, 02:04 PM
Ok so some of you probably have seen this macintosh II i have on my site, now heres the thing, it won't start at all aka no poweron after i hit the power button, been trying to figure it out slightly over the years but as i'm not really used to mac's it's not so easy.
From left to right the psu has 1 orange, 4 red, 5-6 black 1 yellow and 1 white cable, anyone know if there is a way to trick the psu to starting on it's own if you plug in the power cable like you can do with atx psu's? atleast then i'd know if it's the psu or something else.

NeXT
February 6th, 2012, 06:36 PM
For starters, the two 3.6v cells are probably dead. They are needed to supply the latch power foer the PSU to tuen on when you press the power button.
A good substitute for one 3.6v cell is two 1.5v AA batteries.

Elvi
February 15th, 2012, 12:49 PM
Any ideas if it's possbile to hotwire the psu or the batteries so it would start up?

Edit: just mesured the 2 batteries and they arn't dead but i doubt they have enough charge to start the pc, nr 1 3.20V, nr2 0.15V so they arn't dead at all but they might aswell be since they are lithiums.

RWallmow
February 15th, 2012, 01:05 PM
Any ideas if it's possbile to hotwire the psu or the batteries so it would start up?

Edit: just mesured the 2 batteries and they arn't dead but i doubt they have enough charge to start the pc, nr 1 3.20V, nr2 0.15V so they arn't dead at all but they might aswell be since they are lithiums.

Before you go trying to hotwire the PSU, I would replace the batteries, though it sounds like NR1 is still good, but for sake of argument I would replace both. You shouldnt need to replace them with exact matches, like NeXT said you can replace each one with 2x AA or AAA cell batteries. Being you are from Finland I cant tell you where to find battery holders, but if nothing else they are cheap on ebay from china. I have done this in a number of vintage computers, using AA/AAA battery holders makes future replacements VERY easy, plus you can mount the battery holder away from the board so if they leak they wont corrode the board.

Elvi
February 15th, 2012, 01:29 PM
I don't wanna put out any money on this thing before i even know if it's the batteries or the psu that's bad, read somewhere it "should" start with 3.0-6.5V on the pfw line, the white cable so... i tried to jumper from the red +5v to the pfw and nothing, with the mobo disconnected ofcourse.
So any other ideas?

Elvi
February 15th, 2012, 02:43 PM
Just tried to wire in a 3v cell on the battery that didn't have much power left... nothing still doesn't start.

Edit: also suddenly the second battery is showing 2-2.5v charge o_O how is that possible if it's a lithium battery!?

Elvi
March 26th, 2012, 03:15 PM
Is it possible to start this mac with a at or atx psu at all?

scott-k
April 1st, 2012, 10:38 AM
Is it possible to start this mac with a at or atx psu at all?

Yes - I have a Mac II and a IIx running on ATX power supplies. Here's the pinout for the power connector:

Pin # Function
----- --------
1 +12V
2 +5V
3 +5V
4 +5V
5 +5V
6 +5V
7 Ground
8 Ground
9 Ground
10 Ground
11 Ground
12 Ground
13 N/C
14 -12V
15 /PFW

http://support.apple.com/kb/TA39976?viewlocale=en_US

It may not be a good long-term solution, but at least it will let you test the board.

Unknown_K
April 1st, 2012, 12:25 PM
Another issue might be capacitors, I had to rework both of my IIx machines because of leaky caps, the original II will have the same issues. One of the batteries hold PRAM info while the other jump starts the computer (and that one goes dead first). Try reseating the ROM SIMM (forget if that model had SIMM or chips).

Elvi
April 7th, 2012, 07:37 AM
Yes - I have a Mac II and a IIx running on ATX power supplies. Here's the pinout for the power connector:

Pin # Function
----- --------
1 +12V
2 +5V
3 +5V
4 +5V
5 +5V
6 +5V
7 Ground
8 Ground
9 Ground
10 Ground
11 Ground
12 Ground
13 N/C
14 -12V
15 /PFW

http://support.apple.com/kb/TA39976?viewlocale=en_US

It may not be a good long-term solution, but at least it will let you test the board.

I've seen these numbers before but i can't really make heads or tales off them especially pin 13 and 15, doubt a atx or at psu has those.

If i had some shematics then i probably could work it out some day but i've seen none on the net for either at or atx.

RWallmow
April 7th, 2012, 09:07 AM
I've seen these numbers before but i can't really make heads or tales off them especially pin 13 and 15, doubt a atx or at psu has those.

If i had some shematics then i probably could work it out some day but i've seen none on the net for either at or atx.

I am guessing N/C means "No Connection", as it frequently does in pinouts. PFW is power-fail/power-on circuit, something which I am pretty sure doesn't work the same on ATX, and something that would be dangerous to "fake", its purpose in the Mac is to 1. respond to power key on ADB keyboard (less critical) and 2. be able to initiate SHUT DOWN on the Mac in case of thermal runaway or other damaging events. If you really want to fake it and power-up with an ATX supply (and very likely destroy the board) +5v should in theory be applied to PFW to bring the power online.

Elvi
April 7th, 2012, 09:29 AM
I really don't have anything to loose here as i have no spare parts to test with and it won't turn on at all, i guess this would be easier with an AT psu as if the PFW is the one that needs +5 and the rest of the pinns are allready on a AT psu so i'd just have to hit the on switch on the psu... hopefully, thoughts?

RWallmow
April 7th, 2012, 04:40 PM
I really don't have anything to loose here as i have no spare parts to test with and it won't turn on at all, i guess this would be easier with an AT psu as if the PFW is the one that needs +5 and the rest of the pinns are allready on a AT psu so i'd just have to hit the on switch on the psu... hopefully, thoughts?

AT or ATX, either one should supply the voltages needed, but either one will leave the PFW not working as it should, try it at your own risk, but its likely you will toast that thing.

Best bet if you want to see this thing live again would be to replace all the electrolytic capacitors, those are the likely culprits to why its not powering on now. I would say after you have replaced those, and put fresh PRAM batteries in it and it STILL wont power on.....then I would say you have nothing more to loose, those are NOT expensive things to try first, you are looking at about $10-15USD (with postage) in parts and an hour of time. Those shouldn't be TOO expensive of parts in Finland either, there has to be SOME kind of electronics store (local or mail-order) that sells those types of parts, even if its a touch more than they would cost here in the states, if nothing else you can order that stuff for next to nothing from china it you have the time to wait.

In the end its your stuff, if you want to just "apply power" and see, its up to you, just saying I would be trying a few things before that step.

Elvi
April 8th, 2012, 02:24 AM
Shouldn't the capacitor tops be bulgy or leaking if they have failed? i can't see any of that.
Also it doesn't tell me if the PSU itself is bad or not.

scott-k
April 8th, 2012, 05:05 AM
I've seen these numbers before but i can't really make heads or tales off them especially pin 13 and 15, doubt a atx or at psu has those.

If i had some schematics then i probably could work it out some day but i've seen none on the net for either at or atx.

This is what your connector should look like:


http://i1246.photobucket.com/albums/gg614/scott-k/power.jpg


1 Yellow (+12V)
3 Red (+5V)
12 Black (GND)
14 Blue (-12V)

Ground the green wire on the ATX power supply to turn it on.
This powers the Mac directly, so you don't need pin 15.

scott-k
April 8th, 2012, 05:16 AM
Shouldn't the capacitor tops be bulgy or leaking if they have failed? i can't see any of that.
Also it doesn't tell me if the PSU itself is bad or not.

The caps probably won't bulge... Look for a greasy stain around them:

http://i1246.photobucket.com/albums/gg614/scott-k/leaky.jpg

Elvi
April 8th, 2012, 06:04 AM
1 Yellow (+12V)
3 Red (+5V)
12 Black (GND)
14 Blue (-12V)

Ground the green wire on the ATX power supply to turn it on.
This powers the Mac directly, so you don't need pin 15.

Guess this would even be easier with an AT psu, i have a few of those, just start the psu and away we go... hopefully.


The caps probably won't bulge... Look for a greasy stain around them:

http://i1246.photobucket.com/albums/gg614/scott-k/leaky.jpg

Uh oh, i saw a few that i think have leaked, not good :/ never thought those small things were caps tho.

Elvi
April 8th, 2012, 06:43 AM
HAHA would you look at that, it booted right up with a AT psu, nothing wrong except that the OS is busted but i knew that from before, and as i don't have any OS diskettes i can't fix it, the hd seems ok even with the leaking caps... for now.

Thanks alot scott-k now i atleast know that the mobo is somewhat ok so i can play with it, maybe i should open up the mac psu and check it's innards to see how it is, also noticed that the traces to the button has started to flake, that might be a reason it's not booting either.

Elvi
May 30th, 2012, 02:31 PM
Does anyone have the schematic for this mac or know where to find one? trying to figure out of the power button leads are busted, 1 of the 6 pinns seem to be minus and goes almost directly to 1 of the batteries, the other one along side it go to 1 of the caps so i know these 2 work atleast, the other 4 is another matter, i realy can't see where they are going.

Elvi
June 2nd, 2012, 07:50 AM
No one?

Unknown_K
June 2nd, 2012, 12:09 PM
Here is the switch

Elvi
June 3rd, 2012, 11:28 AM
Thanks, i'll see if i can figure it out.

Elvi
June 5th, 2012, 11:14 AM
okay, i havn't been able to identify the ways the traces go except for the 2 on the bottom of the switch in the above image, maybe someone can help?
i've taken a image of the front of the board and under for help
9199
button, top right corner

9200
button pinns top left corner

Elvi
June 5th, 2012, 12:54 PM
Progress :D
i found this video on youtube http://youtu.be/6Mvn5z6AJK4 Jump Starting the Macintosh II and to my surprice it actually awoke so the psu is ok :D
and my next surprice was when i pressed the button on the back and it shut off but starting it again with the extra battery connected to the bad one, no go... so a trace must be bad around the button.

Unknown_K
June 5th, 2012, 01:36 PM
You have leaking capacitors, and one line from the power switch is corroded maybe broken.
So you need to replace the aluminum capacitors, clean up the board, replace the batteries, and check for broken tracks.

Elvi
June 5th, 2012, 01:38 PM
i'm trying to see where the traces go but i can't, theres just no hint at all where they go and i know about the caps but now it boots atleast of the psu, also just noticed that it doesn't give a chime, nothing from the speaker, plugged in and all that.

RWallmow
June 5th, 2012, 01:42 PM
okay, i havn't been able to identify the ways the traces go except for the 2 on the bottom of the switch in the above image, maybe someone can help?
i've taken a image of the front of the board and under for help
9199
button, top right corner

9200
button pinns top left corner
Is it just me or do the traces LOOK bad in that first photo, have you checked the ones that look dark/corroded?

You would need to clip out the dead battery, or its likely going to short whatever new battery you try to jumper onto it, I would be willing to bet those existing batteries have dead shorted internally. Like many of us have said from the beginning, replace those batteries. It might not even be bad traces, but just shorted batteries (however the traces don't look good, so it could be both).

EDIT: Since you have got this thing to power on, you know its worth doing the work to replace the batteries. :listen: :D

Elvi
June 5th, 2012, 01:45 PM
not both batteries are bad, just the 2nd one but i guess i could clip that one out, btw i've never changed surface mounted caps before so i wouldn't know how to or even what specs these caps have.

RWallmow
June 5th, 2012, 01:57 PM
not both batteries are bad, just the 2nd one but i guess i could clip that one out, btw i've never changed surface mounted caps before so i wouldn't know how to or even what specs these caps have.

Surface mount work can be a bit scary at first, I would say practice on something unimportant first if you are worried, but if you can handle through-the-hole soldering its not much worse on these macs. These early macs have pretty large solder pads for most the surface mount caps, they are not too bad to work on. You might need a magnifying glass of some kind to read the values of the capacitors its usually small print on the cans, otherwise maybe someone else can chime in, I don't know the values needed by a Mac II, I have only done an SE/30 myself.

Unknown_K
June 5th, 2012, 01:58 PM
You need tools (like a multi meter) to check for continuity of the traces from point to point. If you do not have troubleshooting knowledge send the machine to somebody who does (local repair shop) to have it fixed, no idea what stuff like that costs in your area.

Elvi
June 5th, 2012, 02:11 PM
i've allready tested the traces from the button but on 2 of the pinns i can't honestly see where they are going, the 2 bigger traces i can see where they are going and the both connect, it's the 2 smaller traces that i can't see where they go.

@ RWallmow large solder pads? these caps have smaller pads than i've tried in any other machine i've changed stuff in, besides that i can't even see the solder pads.

Unknown_K
June 5th, 2012, 02:29 PM
I don't have a Mac II, but I have recapped 3 IIx machines and those used around 15 pieces 47uf 16V capacitors. All of them were in easy to get to areas.

For surface mount capacitors the solder pads are under the part. You don't actually solder the legs, mostly you heatup the pads that stick out and that flows solder to the capacitor legs. There are posts about resoldering methods if you do a search. Even with new capacitors and batteries there is still the chance you need to do board level repairs or replace other components that were damaged from the leak.

Elvi
June 5th, 2012, 02:50 PM
Yes i guess your right about the repairs but with the help of that video i managed to get it going so i can bypass the button if i want to and i think atleast 1 of the small traces to the button that can be seen on the image is probably broken but i could fix that with a new wire on the back if i just could figure out where it goes, the schematic image didn't give much to go after so i don't want to attach a new wire to maybe some wrong place.

On the battery bit, i cut away the battery that only had 1v left in it but let the other one be cause it had over 3.10v in it, maybe that's the clock battery.

thanks anyway this far.

Elvi
June 7th, 2012, 05:23 AM
I'm guessing the top most trace from the button goes to the tokin "black box", if that is the case i don't get any connection, also just today after clipping away the "start" battery i tried my 9v battery on the same pinns and couldn't get the mac to start so i guess the start circuit is offline while the off circuit seems to work.

Elvi
June 24th, 2012, 02:07 AM
I'm wondering if it's possible to exchange the orginal surface mounted caps for more normal thru mobo type caps, there seems to be holes to support this beside the orginal caps but i'm unsure.
What i do know however as these holes have direct connections to the current caps as i've tested for connectivity, so both the surface mounted solder pads and the thru holes seem to be linked but i thought i'd ask to confirm this.
If anyone wants i can upload an image of the area in question.

scott-k
June 25th, 2012, 02:47 AM
I checked my board, and those holes are pretty small... if they're holes at all. They may be traces from one side of the mainboard to the other - I'm not sure.

I used this site to re-cap my Macintosh II (and a IIx, and two IIcx's):

http://inbox.apana.org.au/?p=1342


Personally, I wouldn't try shoving anything through those holes.

scott-k
June 25th, 2012, 02:54 AM
i tried my 9v battery on the same pinns and couldn't get the mac to start

Just curious... Was this a typo, or did you actually apply 9V to those pins? I'm pretty sure the spec calls for a max of 6V

RWallmow
June 25th, 2012, 07:24 AM
I checked my board, and those holes are pretty small... if they're holes at all. They may be traces from one side of the mainboard to the other - I'm not sure.

I used this site to re-cap my Macintosh II (and a IIx, and two IIcx's):

http://inbox.apana.org.au/?p=1342


Personally, I wouldn't try shoving anything through those holes.

That site recommends cleaning the board with brake cleaner (trichloroethylene), which if heated with butane (or some other gases), can become phosgene, which is some deadly stuff. I do most of my soldering with a butane soldering iron (I like it, its portable, has many tips to choose from, and has a fairly wide heat range) and this could be quite dangerous to someone like me if I didn't know better.

This is just an FYI to readers, many people have been hurt or killed welding/soldering things that have been cleaned with brake cleaner, so now you know :-)

scott-k
June 25th, 2012, 12:43 PM
Phosgene... As in First World War chemical weapons? Okay, I'm glad I skipped that step now :-)

Thanks for the heads-up

RWallmow
June 25th, 2012, 01:41 PM
Phosgene... As in First World War chemical weapons? Okay, I'm glad I skipped that step now :-)

Thanks for the heads-up
One and the same....

I have heard stories of people who have died welding on parts that were cleaned with brake cleaner, worse yet are some of the stories of the ones who lived (http://www.brewracingframes.com/id75.htm)....

Not sure how much gas could be produced from soldering vs welding, but I personally would never want to risk that.

Elvi
June 26th, 2012, 03:25 AM
Just curious... Was this a typo, or did you actually apply 9V to those pins? I'm pretty sure the spec calls for a max of 6V

Nope not a typo and i didn't fasten the wires to the battery, just long enough to kick start the PSU and it works everytime.

Btw the battery is low on power so it maxes out at around 7V anyways.