Mac Portable, Dead Battery, Compatible AC Adapters

[JDW]

Most Mac Portables have dead batteries now, and we all know that the Portable won't start up from its AC Adapter without a good battery. However, it has been said that a PowerBook 100 AC Adapter would boot the Macintosh Portable even with a dead battery. I don't know this from personal experience though, just from what I have read on EBAY and in various online forums.

Here is a list of AC Adapters I found at Apple's website:

http://support.apple.com/kb/TA32393

Unfortunately, that web page doesn't mention the Mac Portable. The first AC adapter on that list is the M5140, which is for PowerBook 100. Would anyone know what the model number is for the Macintosh Portable's AC adapter?

Since it has been said that the PowerBook 100's AC Adapter works to boot the Macintosh Portable even if the Portable's battery is dead, but does anyone know if that AC adapter (which can boot the Portable with a dead battery) is the original model M5140 adapter or the replacement model M4662 adapter (or both)?

And what would happen if an M5651 or M5652 were connected to the Macintosh Portable? Would it fry the board? Apple's article says the M5652 would damage the PowerBook 100, so it makes one wonder what would happen to the Macintosh Portable.

I look forward to hearing your thoughts and experiences.

Thank you.

 

[Byrd]

I've both the PB100 (grey) and Portable (white) adapters which I'll check on the model numbers for you today. I can confirm though, that the PB100 adapter on a Portable (with the dead, lead acid battery removed) does not fire up a Portable.

Some time ago, I posted a similar thread:

viewtopic.php?f=10&t=13918&p=134600&sid=380104df66fbfbcff3f353ee8d55b41c#p134600

... now I can't say I've tried the 9V/3A power adapter yet, but it sounds feasable. Keep in mind also that the caps will eventually need to be replaced with tantalum replacements. But, if you've not taken apart a Portable before, get ready for what is actually quite a pleasant experience - it pulls apart like a jigsaw puzzle, with no screws in sight. Just be careful to not snap off any tabs.

JB

 

[JDW]

Byrd, thank you for your reply.

The inspiration for this thread is a conversation I am now having with one of our list members, off-list. He tried to boot the Portable with a 5651 adapter because he wanted to play it safe with a 2A adapter. However, he told me that did not work to boot the machine. He also said that when he originally acquired his Macintosh Portables, they came with a 5136 adapter, which I assume is the model number of the AC Adapter for the original Macintosh Portable. Even so, they will not boot off that adapter either -- no surprises there based on what I've read before about dead Portable batteries.

I did Google up this a few minutes ago.

http://idisk.mac.com/lefevere/Public/THE_PORTABLE_WILL_NOT_BOOT_UP.pdf

I guess there are a variety of things that could prevent booting, including bad capacitors that you spoke of.

 

[ClassicHasClass]

My Portable boots with a dead battery, but I am using a custom adaptor and I believe I had to crank the amps up. I can give you the V/A rating if you want me to dig it out of the closet.

 

[JDW]

If you don't mind the digging, I'd love to know the technical info.

For the record, the individual I am speaking to off-line about his non-bootable Mac Portables told me he has the following adapters:

5136, 1.5A (came with the Mac Portables he acquired, and fail to boot the Portable)

5651, 2A (failed to boot the Portable)

5652, 3A (never tried this one)

And to repeat my earlier post, the PowerBook 100 adapters (which he doesn't have) are:

5140 (original)

4662 (newer, replacement)

 

[ClassicHasClass]

I'll do it when I'm back in town. Ping me in a couple days if I forget.

 

[mcdermd]

5136, 1.5A (came with the Mac Portables he acquired, and fail to boot the Portable)5651, 2A (failed to boot the Portable)

Same as mine. As I recall, the 2A PowerBook adapter boots my Portable with a dead battery but the battery has to be installed (along with the 9v backup battery). I recelled the battery a while back so I can't test that at the moment.

 

[JDW]

mcdermd, the individual I am speaking to off-list provided more info:

• He says he just checked his 5651 adapter (2A version) with a DMM and it started out at 7.7v but then quickly dropped to 0.5v, which indicates that particular adapter may be dead.

• He asks if he can safely use the 5652 adapter (3A version)? He tested it and says it shows a steady 7.8v.

Thanks.

 

[superpantoufle]

Hi all,

After a quick look through my boxes of Mac stuff, here are the adapters I have that are relevant to the topic:

Macintosh Portable Power Adapter Model # M5136Z (output 7.5V / 1.5A)

This is the adapter that came with my Portable (original non-backlit). I bought this Portable second-hand from its original owner a couple of years ago. I confirm it won't allow the Portable to boot.

Would anyone know what the model number is for the Macintosh Portable's AC adapter?

Looks like it is indeed M5136. I guess the Z in my adapter's model number is for Switzerland's specific connector.

Apple Low-Power AC Adapter Model # ADP-17AB (output 7.5V / 2A)

This one came with my PowerBook 100, but the ©1994 year and the strange model number lead me to believe it certainly wasn't its original adapter. Maybe a later replacement?



This one doesn't give my 100 enough power to boot anymore, though it still powers up its screen and allow it to make strange noises… So my 100 runs happily 24/7 for two months now from another 1xx adapter (see below). I can't remember for sure if it booted the Portable, but I don't think so.

Macintosh PowerBook AC Adapter Model # 5140Z (output 7.5V / 2A)

I got one of those with each of my early 1xx PowerBooks (140 and 145B for sure, and I think also with my 150). So they weren't exclusive to the PowerBook 100. They easily boot my Portable. In my experience, for the Portable to boot it had to have its main battery taken out, and I had to try a couple of times (plug and unplug the adapter).



I don't have enough time today to check my later adapters' model numbers, sorry. But since I managed to boot the Portable with a M5140, I never tried anything else. Am I wrong to fear going beyond 2.0A?

 

[JDW]

Am I wrong to fear going beyond 2.0A?

That is precisely what I wish to know. More specifically, will a 5652 adapter (3A version, 7.7v) cause harm to the Macintosh Portable or not?

 

[mcdermd]

I have always thought that maximum amperage output doesn't matter as long as you have enough. It's too much voltage that will kill things.

 

[mcdermd]

Okay, I have tested it here at my desk with my Portable (40MB conner drive, 2MB RAM, Modem). After each change in configuration, I waited ten seconds then briefly pressed both programmer and restart buttons simultaneously three times to reset the power manager before pressing a key on the keyboard to start the machine. My results are:

M5136 Macintosh Portable Adapter (1.5A, 7.5V):

Boots with good battery + 9v PRAM battery: YES

Boots with bad battery + 9v PRAM battery: NO (Starts but there is not enough power to spin the hard drive or the floppy drive)

Boots with no battery + 9v PRAM battery: NO (Starts but there is not enough power to spin the hard drive or the floppy drive)

Boots with no battery - 9v PRAM battery: NO (Starts but there is not enough power to spin the hard drive or the floppy drive)

M5651 PowerBook AC Adapter (2A, 7.5V):

Boots with good battery + 9v PRAM battery: YES

Boots with bad battery + 9v PRAM battery: YES

Boots with no battery + 9v PRAM battery: YES

Boots with no battery - 9v PRAM battery: YES

I should think that the 3A adapter should provide the same results as the 2A adapter.

 

[JDW]

I should think that the 3A adapter should provide the same results as the 2A adapter.

Logically, I agree. If you have a 7.7v PSU that can supply 1A and another 7.7v PSU that can supply 5A, either should work fine in most any situation because the device pulling power from the PSU will take as much electric current as it needs, and no more.

But it appears Apple is siding with Dr. McCoy on this, rather than Mr. Spock:

http://support.apple.com/kb/TA32393

Note that Apple says "Wattage" can destroy the circuit board of some PowerBooks! Their "Warning" says that anything above 19W would destroy a PB100 or PB150. But why? I can understand this if the voltage is too high, but it is really warning about excess voltage here? If so, why not put that instead of Wattage?

The individual with whom I am speaking off-list has a dead M5651 (which does him no good to test further) and a working M5652. Consider well how the 5651 & 5652 output the same voltage of about 7.7v. And yet, the 5651 is rated as 19W on Apple's site (2A), and the 5652 is rated as 24W on Apple's site (3A). The voltage is the same, yet the wattage is different (due to the current rating being different -- i.e., the 5652 supplies more current than the 5651). Now once again consider Apple's WARNING on that web page. If anything greater than 19W will destroy a PowerBook100 (i.e., the 5652 would destroy it), what then would the 5652 do to a Macintosh Portable???

The reason all this matters is because the main battery is dead, the individual who owns it doesn't have the means to get another, and we need to determine if his Portable is really working or not. The only way to determine if the Portable is fried somehow is to either get a working main battery (which is not possible right now), or test an AC adapter. But the only adapters currently in-hand that are working are the original Macintosh Portable adapter (which we all know WON'T boot the Portable that has a dead Main Battery), and the 5652 (7.7v, 24W, 3A). So does anyone have experience booting a Portable off an M5652 AC Adapter?

 

[shred]

I've powered my Mac Portable from an M5651 2A adapter for years (ever since I realised that the original white wall wart was being yellowed by the heat from leaving it plugged in constantly) with no ill effects. However, as others have found, the M5651 will not reliably boot the Portable with the original 3.5" Conner hard drive.

With a compact flash drive, it's just a matter of hitting both the + buttons to reset the power manager and away it goes with or without the main battery present.

I don't know how sophisticated the charging circuit in the Mac Portable is, or how it will respond to a 3A charger if the main battery is dead (or worst case: if it has shorted cells). I suspect that the worst outcome from using a 3A charger would be that it might "blow" the pico fuse soldered to the Portable's main board. The fuse exists to protect the board from over current. I've only seen a Portable with an open-circuit fuse once and I have no idea what the user did to cause it.

@dcdermd: regarding testing with the 9v battery in / out, it won't make any difference - as long as the battery cover is on. The 9v backup battery is switched in mechanically by a micro-switch on the battery compartment door.

 

[techknight]

The only reason why wattage matters, being too many watts kills powerbooks is because of 2 things really.

1 is poor circuit design.

2 is potential overload during a fault condition.

1: If the circuit is designed poorly, it uses the limiting in the power supply's current (wattage) to regulate proceeding voltages/amperages in cascading circuitry. So, if the wattage of a power supply was increased, in return the poorly designed circuit would regulate too "hot" and cause damage. (such as charging a battery).

2: If a fault occurs, such as a short in the battery, or elsewhere in the logic board, the lower current your supply can handle, the better the situation. Why? if the circuit shorts out, there is not as much current there to blow stuff up, maybe heat them up, but the power supply would crowbar before this would happen. If the amperage is higher, there is more current available to the short, which could cause ratings of semiconductors in cascading stages to be exceeded, in turn, cause failure in those stages. aka MAGIC SMOKE

Example of situation 2 would be a car audio amplifier. When bench testing damaged or possibly damaged/repaired car audio amplifiers, I run them at a current limited supply of 12v at 2amps. Why? if a short re-occurs or has occurred in the output stage, it will protect the power SMPS stage. If i supplied it with a high amperage power supply, such as 30amps, it would cause the SMPS stage to completely explode because of the short while attempting to supply voltage rails across nearly a 0 ohm resistance. MAGIC SMOKE

 

[JDW]

I've powered my Mac Portable from an M5651 2A adapter for years (ever since I realised that the original white wall wart was being yellowed by the heat from leaving it plugged in constantly) with no ill effects. However, as others have found, the M5651 will not reliably boot the Portable with the original 3.5" Conner hard drive.

But, shred, your experience conflicts with that of mcdermd...

I have tested it here at my desk with my Portable (40MB conner drive, 2MB RAM, Modem). After each change in configuration, I waited ten seconds then briefly pressed both programmer and restart buttons simultaneously three times to reset the power manager before pressing a key on the keyboard to start the machine. My results are:
M5651 PowerBook AC Adapter (2A, 7.5V):

Boots with good battery + 9v PRAM battery: YES

Boots with bad battery + 9v PRAM battery: YES

Boots with no battery + 9v PRAM battery: YES

Boots with no battery - 9v PRAM battery: YES

So who is right? Can Portables with the original 40MB Apple branded Conner drive be booted with the M5651 or not? One says yes, another no. But I would like to know who is correct and why. Is it, shred, that you didn't reset the power manager like mcdermd did?

With a compact flash drive, it's just a matter of hitting both the + buttons to reset the power manager and away it goes with or without the main battery present.

What flash drive do you use, and where did you buy it?

Thanks!

 

[shred]

Hi JDW,

Note that I said the M5651 doesn't "reliably" boot my Mac Portable with the Conner 3.5" hard drive. It worked sometimes, not others and I always reset the power manager before booting.

There's a thread I started called "Ah, it's the serenity" or something like that on getting compact flash to go in the Portable. I wired up my own cable to go from the Portable logic board to a 50 way SCSI adapter, then SCSI -> IDE > Compact Flash. It's not the neatest solution, but it goes well and the Portable is ultra quiet now.

[edit] My M5651 is running from 240v. It shouldn't make any difference to the output, but you never know.

 

[JDW]

Thanks for the tip on that other thread, shed. Here it is:

viewtopic.php?f=10&t=4477

Funny too, seeing that I actively participated in it! Ha ha. Totally forgot about it. And my closing post was to say that one of the links given resulted in a 404 error.

 

[JDW]

The only reason why wattage matters, being too many watts kills powerbooks is because of 2 things really...

But when you speak of "Watts" you are talking about the combination of voltage and current, not just current alone. However, if an AC adapter puts out a steady voltage, then it would only be "too much current" that would increase the "wattage," which is what you mention kills the Mac Portable. But if we admit that "too much current kills," then how is it that the main 9v battery of the Portable wouldn't be a problem too? Because can't that lead acid battery supply more than 2 Amps of current? And as far as I know, the battery is just a normal battery, and nothing within the battery itself actively limits the current output.

I'm still trying to figure out what a rock solid 9.00v power supply (AC adapter, what have you) would be a problem if it has the upper potential of delivering more than 2 or so Amps of current. If the voltage of that supply isn't fluctuating, who case if it supplies a max of 3A or 4A or even 10A? Because again, even the main 9v battery of the Portable doesn't have built-in current limiting, does it?