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Mac Portable, Dead Battery, Compatible AC Adapters
- Thread starter JDW
- Start date
digitalrampage
Well-known member
:approve: My two cents, having read portions of this board are the following - P.S I own 18 Mac Portables, and have been studying them for a long time.
1. The whole thing about removing the batteries and putting a 9v feed in on the PRAM battery thing is just stupid, the whole idea of the battery cradle is to temporarily give the logic a bit of juice while swapping in and out the main battery to keep date/time. Amazingly, the machine will actually turn on with a brand new 9v battery if the hard disk is disconnected and you don't try and boot from a floppy. Of course, this will only work if the battery cover is off, and for a few minutes before killing the battery.
2. With the main battery removed, and the battery cover on, any PSU of 7.5v and 2a or over should turn over the machine, however I know some of my units will only turn over with the 3A 7.5v PSU's... Not sure why, as some get very edgy with the 3A PSU.
3. I always personally stick to the 7.5v 2A adaptors for safety, but always revert to the 1.5a cream adaptor when I have a good SLA battery in, the charge circuit seems to suck more amperage, and charge faster when available and in my experience shortened the overall battery life.
4. The Power controller on the Mac Portable is very funny and moving between power sources can scramble the boards a bit. Pressing both the reset and interrupt together a few times usually fixes them up, but I have had times where i've had to leave boards for a few days without power for them to be happy again.
5. If you are not going to rebuild the main 6v 5.0ah SLA, my experience is - best to remove both batteries and put back on the battery cover before connecting power supplies.
The Mac Portable is a very interesting machine, they really are one of my favourite mac's. However they are also the most unstable mac's without the SMD caps being replaced and a good PSU.
I only ask everyone, test your Apple PSU's before plugging them in, as many of those Cream and Grey PSU's are going supernova now, and dishing out either way too little, or way too much power.
Hope I've offered something of use to someone here.
1. The whole thing about removing the batteries and putting a 9v feed in on the PRAM battery thing is just stupid, the whole idea of the battery cradle is to temporarily give the logic a bit of juice while swapping in and out the main battery to keep date/time. Amazingly, the machine will actually turn on with a brand new 9v battery if the hard disk is disconnected and you don't try and boot from a floppy. Of course, this will only work if the battery cover is off, and for a few minutes before killing the battery.
2. With the main battery removed, and the battery cover on, any PSU of 7.5v and 2a or over should turn over the machine, however I know some of my units will only turn over with the 3A 7.5v PSU's... Not sure why, as some get very edgy with the 3A PSU.
3. I always personally stick to the 7.5v 2A adaptors for safety, but always revert to the 1.5a cream adaptor when I have a good SLA battery in, the charge circuit seems to suck more amperage, and charge faster when available and in my experience shortened the overall battery life.
4. The Power controller on the Mac Portable is very funny and moving between power sources can scramble the boards a bit. Pressing both the reset and interrupt together a few times usually fixes them up, but I have had times where i've had to leave boards for a few days without power for them to be happy again.
5. If you are not going to rebuild the main 6v 5.0ah SLA, my experience is - best to remove both batteries and put back on the battery cover before connecting power supplies.
The Mac Portable is a very interesting machine, they really are one of my favourite mac's. However they are also the most unstable mac's without the SMD caps being replaced and a good PSU.
I only ask everyone, test your Apple PSU's before plugging them in, as many of those Cream and Grey PSU's are going supernova now, and dishing out either way too little, or way too much power.
Hope I've offered something of use to someone here.
JDW
Well-known member
digitalrampage, thank you for your feedback. I am especially grateful of your words because who among us has so many Mac Portables? My goodness!
But my question was not directly answered by what you wrote. And perhaps that is because you lack a "variable" power supply. The situation is that an associate of mine who owns a Mac Portable cannot get it to work. He has adapters but none of them will boot the Portable and one of them, which should have worked, tested dead. So he lacks the required "working" adapters to test what you wrote. However, he has a "variable voltage" power supply. But before I instruct him to go ahead and connect that PSU to his Portable to test and see what happens, I first want to know who among us has done this. Yes, yes, I know many of you read this have tested AC ADAPTERS. But that is not the same as using a true variable-voltage power supply. I am not sure if my associate has a supply which also allows him to limit the Current too. He only told me he can vary the Voltage.
So who among us has connected a variable voltage power supply (NOT an AC Adpater) and successfully booted a Portable (internal hard drive included) and used that long enough to determine that such a power supply (at a particular set voltage and current) will NOT harm the Portable? That is what I wish to know. Surely there is at least one Mac Portable owner out there reading this who has tested this at least once.
I look forward to your replies.
But my question was not directly answered by what you wrote. And perhaps that is because you lack a "variable" power supply. The situation is that an associate of mine who owns a Mac Portable cannot get it to work. He has adapters but none of them will boot the Portable and one of them, which should have worked, tested dead. So he lacks the required "working" adapters to test what you wrote. However, he has a "variable voltage" power supply. But before I instruct him to go ahead and connect that PSU to his Portable to test and see what happens, I first want to know who among us has done this. Yes, yes, I know many of you read this have tested AC ADAPTERS. But that is not the same as using a true variable-voltage power supply. I am not sure if my associate has a supply which also allows him to limit the Current too. He only told me he can vary the Voltage.
So who among us has connected a variable voltage power supply (NOT an AC Adpater) and successfully booted a Portable (internal hard drive included) and used that long enough to determine that such a power supply (at a particular set voltage and current) will NOT harm the Portable? That is what I wish to know. Surely there is at least one Mac Portable owner out there reading this who has tested this at least once.
I look forward to your replies.
mcdermd
Well-known member
What do I risk in hooking up a variable voltage supply to my Portable that is running in good condition? My brother has all sorts of Tektronix equipment including a variable voltage supply module but I'd be loathe to power my Portable from it if there was a chance of harming it.
techknight
Well-known member
you want to keep the voltage CONSTANT. dont variate the voltage. The DC-DC converters in theory should handle that, but itll put more stress on them 
techknight
Well-known member
ok. Question: Can you run a portable solely on the 9V connector.
Answer: YES. You can. I tried it, it works. Idles at 1.80amps, takes about 2.2 amps surge to spin up the drive. There is a catch. You must have the battery cover removed. Why? the 9v isnt connected to the circuit at all until the saftey interlock is disengaged. The interlock switches out the 6V battery and switches in the 9V battery when the cover is slid off and removed.
Is it advisable? no. Why? it runs the switching regulators harder/hotter. Heat shortens the lifetime of components in the long run.
I cant get my backlit portable to solely run off the AC adapter input, there is too much voltage drop on the 5V switching regulator when loaded, so I have to mod the circuitry so that I can
Answer: YES. You can. I tried it, it works. Idles at 1.80amps, takes about 2.2 amps surge to spin up the drive. There is a catch. You must have the battery cover removed. Why? the 9v isnt connected to the circuit at all until the saftey interlock is disengaged. The interlock switches out the 6V battery and switches in the 9V battery when the cover is slid off and removed.
Is it advisable? no. Why? it runs the switching regulators harder/hotter. Heat shortens the lifetime of components in the long run.
I cant get my backlit portable to solely run off the AC adapter input, there is too much voltage drop on the 5V switching regulator when loaded, so I have to mod the circuitry so that I can
reallyrandy
Well-known member
It seems like there has to be someoneout there that either rebuilds these batteries or knows how. I'd love to see my portable boot up. I don't even know if it works.
JDW
Well-known member
What are your thoughts on the following, where the seller (DWBOWERS) claims, "This Portable boots and runs fine without the battery using the included PowerBook power supply"?
http://www.ebay.com/itm/Macintosh-Portable-Vintage-Computer-Used-by-NASA-6MB-RAM-Excellent-condition-/140807426423?pt=US_Vintage_Computers_Mainframes&hash=item20c8c6d177#ht_500wt_922
He also has a backlit one too, in which listing he claimed the same thing about the PowerBook adapter until I contacted him about reliability, directing him to this thread. I wrote him 3 times via EBAY, but he merely changed his listing without replying back to me at all. I find that odd in light of his excellent reputation score and wonderful photos. And it brings up the same issue we've pondered in this thread — it is really safe to use a PowerBook adapter to owner a Portable in the long term? We really didn't come to any definitive conclusion in this thread, other than to deed TechKnight's warning about the potential for burned down resistors, as well as less than reliable booting (unless you've replaced the hard drive with a flash drive).
Anyway, here's the backlit one:
http://www.ebay.com/itm/Macintosh-Portable-Backlit-Model-M5126-with-Battery-Power-Adapter-and-Case-/140807393958?pt=US_Vintage_Computers_Mainframes&hash=item20c8c652a6
http://www.ebay.com/itm/Macintosh-Portable-Vintage-Computer-Used-by-NASA-6MB-RAM-Excellent-condition-/140807426423?pt=US_Vintage_Computers_Mainframes&hash=item20c8c6d177#ht_500wt_922
He also has a backlit one too, in which listing he claimed the same thing about the PowerBook adapter until I contacted him about reliability, directing him to this thread. I wrote him 3 times via EBAY, but he merely changed his listing without replying back to me at all. I find that odd in light of his excellent reputation score and wonderful photos. And it brings up the same issue we've pondered in this thread — it is really safe to use a PowerBook adapter to owner a Portable in the long term? We really didn't come to any definitive conclusion in this thread, other than to deed TechKnight's warning about the potential for burned down resistors, as well as less than reliable booting (unless you've replaced the hard drive with a flash drive).
Anyway, here's the backlit one:
http://www.ebay.com/itm/Macintosh-Portable-Backlit-Model-M5126-with-Battery-Power-Adapter-and-Case-/140807393958?pt=US_Vintage_Computers_Mainframes&hash=item20c8c652a6
Just rebuild the battery and you take no risk at all. It's the easiest battery I know from a laptop to rebuild.
In the end, why would you take any risk if you can perfectly buy the original cells brand new from the Manufacturer ?
You need 3x of these:
http://cellpacksolutions.com/Search_Data_Sheet.asp?ID=0800-0004
For only 22.5£ or about 35USD you can have recell your original battery and it will be good for at least 5 years ( if you don't let it drain completely ).
I have recelled the battery of all my Mac Portables: the oldest is now about 5 years old and frequently charged about 4x times a week nevertheless with a full charge and LCD & HDD always On + rest mode disable it still lasts over 3 hours.
Another argument is that Mac Portables with the original white power adapter and a rebuild battery a worth more than one with a dead battery and a PB100 adapter, not only from a collector's perspective but also on Ebay for example.
In the end, why would you take any risk if you can perfectly buy the original cells brand new from the Manufacturer ?
You need 3x of these:
http://cellpacksolutions.com/Search_Data_Sheet.asp?ID=0800-0004
For only 22.5£ or about 35USD you can have recell your original battery and it will be good for at least 5 years ( if you don't let it drain completely ).
I have recelled the battery of all my Mac Portables: the oldest is now about 5 years old and frequently charged about 4x times a week nevertheless with a full charge and LCD & HDD always On + rest mode disable it still lasts over 3 hours.
Another argument is that Mac Portables with the original white power adapter and a rebuild battery a worth more than one with a dead battery and a PB100 adapter, not only from a collector's perspective but also on Ebay for example.
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JDW
Well-known member
Why? Because even a newly rebuilt battery will die in time. And because I really wouldn't need a battery since the Portable is not so "portable." And because even a newly rebuilt battery will run down over time, prompting me to either keep it perpetually connected (which I do not want to do), or connect, disconnect, and connect it frequently. Otherwise, the battery voltage will get too low, and I've read that such is a big no-no with Portable batteries.
Hence, it makes much more sense, and it is much more convenient, if we could "safely" use an AC adapter to power the Portable, without the need for any batteries inside it.
Hence, it makes much more sense, and it is much more convenient, if we could "safely" use an AC adapter to power the Portable, without the need for any batteries inside it.
If you want to use your Mac Portable on a PSU only: that's fine.
I prefer to keep my collection as original as possible, so that's with a working battery.
Let's be realistic: what's 44USD for a working battery ?
You pay 5x times that much for a replacement Lithium-ion battery for a new laptop now and it's dead in 2 or 3 years.
As for the draining of the Mac Portable's battery: yes it drains his battery, however with the logic board recapped it takes a fully charged battery 2,5 weeks to drain so if you charge it regularly the draining is not an issue at all.
I feel very comfordable with a Mac Portable lasting 3 hours on battery power, with all power savings disabled. Set them on and it's even longer.
There aren't many new laptops around that will beat this time, only a few with very expensive one's with SSD drives...
I prefer to keep my collection as original as possible, so that's with a working battery.
Let's be realistic: what's 44USD for a working battery ?
You pay 5x times that much for a replacement Lithium-ion battery for a new laptop now and it's dead in 2 or 3 years.
As for the draining of the Mac Portable's battery: yes it drains his battery, however with the logic board recapped it takes a fully charged battery 2,5 weeks to drain so if you charge it regularly the draining is not an issue at all.
I feel very comfordable with a Mac Portable lasting 3 hours on battery power, with all power savings disabled. Set them on and it's even longer.
There aren't many new laptops around that will beat this time, only a few with very expensive one's with SSD drives...
JDW
Well-known member
Since the Portable would not be my primary computer, nor the only vintage Mac in my collection, regularly charging of the battery once every 2 or 3 weeks would be a burden indeed. That's especially true if you've got a family, young kids, a busy job, etc., which may lead to your forgetting to charge the battery at times. That may not be true for everyone, especially if you use the Portable often. But realistically, who among us is so willing to faithfully charge the battery every 2 to 3 weeks? And who among us could keep that up for 2 to 3 years (whatever the life is of the replacement battery)? And who really wants to replace a $45 battery every 2-3 years if the Portable isn't used often? Perhaps there are a few, but I am not among them.
So I think you can see my point. Powering it off a dedicated PSU (benchtop power supply) really isn't desirable either as most people don't own one, and they are rather big and bulky. When I speak of an "AC Adapter" I am referring to a compact PowerBook AC Adapter, which the EBAY seller is referring to, and which we have discussed earlier in this thread. But as discussed previously, TechKnight believes that long term use of such could fry some onboard resistors. He simply doesn't know which resistors. I suppose if we did know which resistors, we could theoretically replace them with higher wattage versions and be done with the worry altogether. If so, that might be the best solution all around.
So I think you can see my point. Powering it off a dedicated PSU (benchtop power supply) really isn't desirable either as most people don't own one, and they are rather big and bulky. When I speak of an "AC Adapter" I am referring to a compact PowerBook AC Adapter, which the EBAY seller is referring to, and which we have discussed earlier in this thread. But as discussed previously, TechKnight believes that long term use of such could fry some onboard resistors. He simply doesn't know which resistors. I suppose if we did know which resistors, we could theoretically replace them with higher wattage versions and be done with the worry altogether. If so, that might be the best solution all around.
Dennis Nedry
Well-known member
Coming in VERRRRY late to the discussion, I would like to add that using some power adapters with excessively high current ratings can damage equipment. Say that you pick up a really cool looking, medieval 5V, 10A power adapter and hook it up to a couple of 7400 series chips for a school project. And they blow right up and smoke and bubble. WHY?? It was the right voltage and you only needed 1 mA! It was not actually the right voltage when you ran it with such little current.
Unless a power adapter contains a regulator to overcome it, it has internal resistance that directly affects the output voltage over the entire range of current, starting at zero. When this 5V, 10A adapter was designed, it may have initially had an open circuit output voltage of 5V, but when test technician intern ID X hooked up his awesome heatsinked potentiometer from high school to load it down, something very bad happened.
He dropped the resistance lower and lower while watching the current climb, and while one might expect this resistance to be 0.5Ω after visiting Ohm's law (5V ÷ 10A = 0.5Ω), he actually had to turn the resistance all the way down to 0.27041Ω before he reached 10 Amps. Then he tested the output voltage under this load and it was WRONG - 2.29587V. Well he can fix that.
So, eager to get this thing working and impress the other guys in the only way he knows how - sheer SPEED, the guy cracked open the transformer and began adding extra output windings to the transformer. Current and voltage went up a little with each extra winding, so he had to turn up his pot a little each time too. Finally, after more than doubling the magnet wire that was there originally, he was satisfied when his readings were 5V, 10A. So was his boss - it does exactly what the spec says - 5V at 10A. TEST PASS --> TIMELINE OBJECTIVE COMPLETE AHEAD OF SCHEDULE --> SHIP IT --> PROMOTE INTERN X TO COFFEE MACHINE SUPERVISOR --> HAVE A REFRESHING CUP OF COFFEE. (Kidding in Dilbert fashion of course. )
Going back and testing the power adapter for open circuit voltage after this modification, it is now 10.889V because of 0.22959Ω internal resistance! Test the open circuit voltage of handful of your power adapters to see how true this story actually is.
Seriously, though, companies are VERY likely to be aware of this as they select/design power adapters, and they choose the most cost-effective one that works fine specifically with the device they bundle it with. When we try to use a high current rated adapter with a low current device, even if it's the same rated voltage, that's where we could run into problems if we don't consider voltage under different loads. I don't know if this applies to the PowerBook vs Portable power adapters damaging the PowerBook 100 but it could be tested.
Unless a power adapter contains a regulator to overcome it, it has internal resistance that directly affects the output voltage over the entire range of current, starting at zero. When this 5V, 10A adapter was designed, it may have initially had an open circuit output voltage of 5V, but when test technician intern ID X hooked up his awesome heatsinked potentiometer from high school to load it down, something very bad happened.
He dropped the resistance lower and lower while watching the current climb, and while one might expect this resistance to be 0.5Ω after visiting Ohm's law (5V ÷ 10A = 0.5Ω), he actually had to turn the resistance all the way down to 0.27041Ω before he reached 10 Amps. Then he tested the output voltage under this load and it was WRONG - 2.29587V. Well he can fix that.
So, eager to get this thing working and impress the other guys in the only way he knows how - sheer SPEED, the guy cracked open the transformer and began adding extra output windings to the transformer. Current and voltage went up a little with each extra winding, so he had to turn up his pot a little each time too. Finally, after more than doubling the magnet wire that was there originally, he was satisfied when his readings were 5V, 10A. So was his boss - it does exactly what the spec says - 5V at 10A. TEST PASS --> TIMELINE OBJECTIVE COMPLETE AHEAD OF SCHEDULE --> SHIP IT --> PROMOTE INTERN X TO COFFEE MACHINE SUPERVISOR --> HAVE A REFRESHING CUP OF COFFEE. (Kidding in Dilbert fashion of course.
)Going back and testing the power adapter for open circuit voltage after this modification, it is now 10.889V because of 0.22959Ω internal resistance! Test the open circuit voltage of handful of your power adapters to see how true this story actually is.
Seriously, though, companies are VERY likely to be aware of this as they select/design power adapters, and they choose the most cost-effective one that works fine specifically with the device they bundle it with. When we try to use a high current rated adapter with a low current device, even if it's the same rated voltage, that's where we could run into problems if we don't consider voltage under different loads. I don't know if this applies to the PowerBook vs Portable power adapters damaging the PowerBook 100 but it could be tested.
techknight
Well-known member
Which means its not 5V. lol. any power supply that is not regulated/loaded properly will produce voltages way different than what is written on the face.
If you have a TRUE 5V output power supply (regulated, etc..) then you cant damage anything. So 5V damaging a circuit that uses 5V is a myth unless the power supply is producing a voltage other than 5V. Or there is a problem in the circuit that causes excessive current draw, then you get a cascading failure, etc.. But then that wasnt the power supplies fault.
so if i had a 5V 200amp power supply hooked to a couple of 74XX chips, they arnt gonna blow. IF 5V = 5V. Just because a power supply is rated for excessive current, doesnt automatically assume it can damage anything.
Given proper regulation/load its fine..
But what you did say definitely a trap for young players that dont know about regulation. thats for sure. What you say is true if the 5V =/= 5V but then technically it isnt 5V is it... Only under proper regulation/load.
So, the way it should have been worded is: Using an Unregulated 5V power supply with excessive current CAN/WILL damage equipment.
Anyway, I know what you mean though, hence why you mentioned "some" power supplies. }
BUT MA, BLOWIN STUFF UP IS FUUUUUNNNN!!!!!! For example, i plugged the transformer connector in backwards while working on a Mackie 1202 Mixer that someone spilled coffee in. WHOOOPS. some caps went kerplow...
With all that aside, I dont know if the PB1XX adapters are regulated or not. if its SMPS, its fine. Anyway, I do know that some car audio equipment, they do a 30% overwind on the secondary windings of the switching transformer that feed the output rails. Running at full swing, loaded or not would blow every cap in the filter section, they arnt rated for the excess voltage. But luckily its a regulated power supply. So it keeps itself in tight feedback for output voltages. the overwind is there for peak current demand when the output section calls for it.
Not trying to start an argument, what you say IS correct in certain conditions, just bustin ya chops.
JDW
Well-known member
TechKnight, I often see EBAY Sellers of Mac Protables claim that they can operate the Portable perfectly, even without the main battery, by using a PowerBook 100 AC adapter. (We discussed a couple model numbers of these supposedly compatible adapters earlier in this thread.) The question therefore becomes, "are these PB adapters 'regulated'?" And if we would say that they are "regulated," are they regulated enough for a Mac Portable's electrical "load"? Evidence presented earlier in this thread seems to indicate an answer of "no" to that.
Now if someone here would kindly ship me a working Portable, and several AC adapters, with the understanding this is a scientific experiment that may damage something, we could perhaps find out once and for all, putting this 20+ year old question to rest.
Now if someone here would kindly ship me a working Portable, and several AC adapters, with the understanding this is a scientific experiment that may damage something, we could perhaps find out once and for all, putting this 20+ year old question to rest.
Dennis Nedry
Well-known member
You make it sound like I was wrong when I clearly was not! How dare you!! :O -> > ->
-> :scrambled:
hahaha :lol:
I have actually made that mistake once with some 7400 chips. I blindly chopped off a 4.5V adapter and wired it in, as the range is 4.5-5.5 for the ones I had. I blew 'em (no smoke though) and when I tested the voltage it was up somewhere around 8V open circuit. DANG
That was nothing compared to when I blew an I/O pin on my awesome HC12 demo board. That was very tragic.
If there actually are people out there trying to learn from what I said here, technight has a valid point -- it isn't exactly clear what I was saying. In theory, if you have a 5V adapter and the current rating is high enough, or higher, or MUCH HIGHER, that will work perfectly fine.
This is usually true in the real world because of voltage regulators, but sometimes regulators aren't used so the rated voltage of those power adapters only comes out correct at the rated current. You should either pick an adapter that matches both the voltage and current, or you should test the adapter with a voltmeter. If the voltage is correct under no load (just your voltmeter attached), then you know that it is regulated and it will be fine under smaller-than-rated current loads.
->
hahaha :lol:
I have actually made that mistake once with some 7400 chips. I blindly chopped off a 4.5V adapter and wired it in, as the range is 4.5-5.5 for the ones I had. I blew 'em (no smoke though) and when I tested the voltage it was up somewhere around 8V open circuit. DANG
That was nothing compared to when I blew an I/O pin on my awesome HC12 demo board. That was very tragic.
If there actually are people out there trying to learn from what I said here, technight has a valid point -- it isn't exactly clear what I was saying. In theory, if you have a 5V adapter and the current rating is high enough, or higher, or MUCH HIGHER, that will work perfectly fine.
This is usually true in the real world because of voltage regulators, but sometimes regulators aren't used so the rated voltage of those power adapters only comes out correct at the rated current. You should either pick an adapter that matches both the voltage and current, or you should test the adapter with a voltmeter. If the voltage is correct under no load (just your voltmeter attached), then you know that it is regulated and it will be fine under smaller-than-rated current loads.
techknight
Well-known member
hahahahahahahaha. It was all fun. hehe. When it comes to blowing up stuff, I think i am the master of it. lol. But thats how you learn. I once blew out 30 op-amps in a Samson powered mixer once years ago because of a polarity issue on the +/-15v rails. I stuck a 7815 in place of the 7915 by accident. Whoops.You make it sound like I was wrong when I clearly was not! How dare you!! :O -> >-> :scrambled:
hahaha :lol:
I have actually made that mistake once with some 7400 chips. I blindly chopped off a 4.5V adapter and wired it in, as the range is 4.5-5.5 for the ones I had. I blew 'em (no smoke though) and when I tested the voltage it was up somewhere around 8V open circuit. DANG
That was nothing compared to when I blew an I/O pin on my awesome HC12 demo board. That was very tragic.
If there actually are people out there trying to learn from what I said here, technight has a valid point -- it isn't exactly clear what I was saying. In theory, if you have a 5V adapter and the current rating is high enough, or higher, or MUCH HIGHER, that will work perfectly fine.
This is usually true in the real world because of voltage regulators, but sometimes regulators aren't used so the rated voltage of those power adapters only comes out correct at the rated current. You should either pick an adapter that matches both the voltage and current, or you should test the adapter with a voltmeter. If the voltage is correct under no load (just your voltmeter attached), then you know that it is regulated and it will be fine under smaller-than-rated current loads.
JDW: I think they are regulated, SMPS based supplies. I cant verify for sure as I dont have a PB100 adapter. only one that came with my PB145. I forget what it was rated for. But its rock solid no load at 7.5V so that means its regulated/SMPS based.
i have an iHome 7.5V ipod dock adapter too, its SMPS based and rated for 2A. Same deal with my portable. But if i hook a 9V adapter up to the 9V battery terminals it works fine. But it draws close to 2A though. If i hook in the 7.5V adapter I have through the battery connection, it wont hold. exceeds the 2A limit as soon as the backlight kicks on, the machine poof shuts off.
Oh P.S. I just blew an 8051 based Micro today lol. I had a keypad apart for screwing around with, the UART wires were black and red, 12V power were white and green. at least now i know. lol. I thought black and red was power, hooked up 12V and blew a hole streight in a 1995 date code 8051 micro. whoops.
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JDW
Well-known member
TechKnight, if a truly regulated PSU is all that is needed to guarantee a Portable won't fry any circuitry over time (with or without the stock batteries attached), why not just buy a suitable PSU from JAMECO or DigiKey? One could just hack off the connector of a stock Mac Portable PSU and wire it to the regulated PSU, right? Wouldn't that be the ideal solution here?
techknight
Well-known member
Oh i have multiple ways to do it. I just need to pick the best one that works for me. I just need to take it to my shop one day and put it on the bench power supply and figure out the EXACT current draw at different voltage points.
