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Troublesome Macintosh Portable M5120 - Need some help


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the Hybrid doesnt look too bad, its better compared to every one ive seen so far. But, i do see some resistor damage. 

 

You are getting random RAM errors. 

 

There is a handful of things that can cause this. the hybrid could be causing noisy voltage/voltage fluctuations that may only be seen with a scope. the PMGR could be causing the startup issues. 

 

Also, its equally possible the 244/245 and various logic chips above and to the right of the CPU are going bad. 

 

The portable ive ssen sooo many different weird issues and not all of them are fixable. 

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19 hours ago, techknight said:

I will say that i see what appears to be some cracking in the solder joints on the Hybrid as well. Could be the camera/flash, but might want to double check that. Could be part or all of your issue. 

There was no flash intentionally, so definitely won't be that. Mind giving me an idea of where you see that? I of course could reflow the entire hybrid. I didn't see the resistor damage you mentioned but I'm new to this board. And seriously, thanks. 

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20 hours ago, Amiga of Rochester said:

There was no flash intentionally, so definitely won't be that. Mind giving me an idea of where you see that? I of course could reflow the entire hybrid. I didn't see the resistor damage you mentioned but I'm new to this board. And seriously, thanks. 

 

These particular boards are like dealing with an ex-wife or something. They are a real pain in the ass. 

 

You have to have an eye for things like this, and I can spot that kinda stuff almost instantly anymore. Just grab a magnifying glass and inspect the solder joiints on the hybrid parts. 

 

Also, look at the resistors, you can see some "lifting" in the blue protective film that goes over the carbon film resistors. That is an issue. Could be natural, could be capacitor goo. 

Edited by techknight
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On 3/24/2021 at 9:04 PM, techknight said:

 

These particular boards are like dealing with an ex-wife or something. They are a real pain in the ass. 

 

You have to have an eye for things like this, and I can spot that kinda stuff almost instantly anymore. Just grab a magnifying glass and inspect the solder joiints on the hybrid parts. 

 

Also, look at the resistors, you can see some "lifting" in the blue protective film that goes over the carbon film resistors. That is an issue. Could be natural, could be capacitor goo. 

I looked over the board and in person I don't see any lifting, it's all smooth and tight.

 

Also, was thinking, if its bad ICs, how does it boot at all. Usually bad logic gates, you wouldn't have it work at all. I guess I will just let the customer know there's many possible causes and we could spend a lot of money and still make no progress. These boards sucks.

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On 3/25/2021 at 5:52 PM, Amiga of Rochester said:

I looked over the board and in person I don't see any lifting, it's all smooth and tight.

 

Also, was thinking, if its bad ICs, how does it boot at all. Usually bad logic gates, you wouldn't have it work at all. I guess I will just let the customer know there's many possible causes and we could spend a lot of money and still make no progress. These boards sucks.

 

Oh ive seen intermittent ICs. ive probably changed hundreds in my life. 

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19 hours ago, techknight said:

 

Oh ive seen intermittent ICs. ive probably changed hundreds in my life. 

I need to order some capacitors, which ICs should I replace? I'm just going to try it for the sake. I am definitely going off your experience, I figure you have had the time invested. It's like Amigas for me, I know a lot about those from my time working on them.

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19 hours ago, Amiga of Rochester said:

I need to order some capacitors, which ICs should I replace? I'm just going to try it for the sake. I am definitely going off your experience, I figure you have had the time invested. It's like Amigas for me, I know a lot about those from my time working on them.

 

Yeah. ive never seen or own an amiga in my life. or used one. They just were not that common at least where I grew up. it was all macs and PCs. 

 

same with SGI and all the other "exotics" 

 

Anyways. There is a 74LS244 or 245 to the upper right corner of where the CPU is, and then there are little logic ICs below that like a 74LS02, etc... ive seen those go bad and do some weird things. 

 

But i still think we have Hybrid/PMGR issues. they are hard to troubleshoot, i just swap em when I get parts boards. 

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21 hours ago, techknight said:

 

Yeah. ive never seen or own an amiga in my life. or used one. They just were not that common at least where I grew up. it was all macs and PCs. 

 

same with SGI and all the other "exotics" 

 

Anyways. There is a 74LS244 or 245 to the upper right corner of where the CPU is, and then there are little logic ICs below that like a 74LS02, etc... ive seen those go bad and do some weird things. 

 

But i still think we have Hybrid/PMGR issues. they are hard to troubleshoot, i just swap em when I get parts boards. 

any chance you got one I can buy? I don't have a working hybrid to confirm with. 

I might have to just call it a lose, I don't want to spend a lot of money on something I might not solve. figured i'm already ordering some ics I could try swapping those...but seems less and less likely the issue.

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20 hours ago, Amiga of Rochester said:

any chance you got one I can buy? I don't have a working hybrid to confirm with. 

I might have to just call it a lose, I don't want to spend a lot of money on something I might not solve. figured i'm already ordering some ics I could try swapping those...but seems less and less likely the issue.

 

I used up everything I had. i have boards here that belong to other people who are stuck in the same situation. 

 

Thats the problem with the Portable. 

 

the PMGR has to be reverse-engineered and replicated which will take alot more effort than I have. As far as the Hybrid, i need to finish the design. 

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21 hours ago, techknight said:

 

I used up everything I had. i have boards here that belong to other people who are stuck in the same situation. 

 

Thats the problem with the Portable. 

 

the PMGR has to be reverse-engineered and replicated which will take alot more effort than I have. As far as the Hybrid, i need to finish the design. 

You make me feel far better :) Any idea on this Classic I have that doesn't see SIMM ram? I have a thread on it. Could use any guidance. Plan to just replace most of the logic ICs related to RAM :( 

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On 3/26/2021 at 8:49 PM, Amiga of Rochester said:

You make me feel far better :) Any idea on this Classic I have that doesn't see SIMM ram? I have a thread on it. Could use any guidance. Plan to just replace most of the logic ICs related to RAM :( 

 

I havent worked on a classic since about 2000 or so. So that one I am not sure of. Everything I ever saw were SE/30 boards and Portables. maybe an LC here and there. 

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Reading this discussion makes me glad I don't have a non-backlit Portable (I was lucky to have managed to find the somewhat less common backlit model, which has a different logic board design that doesn't seem to have these kinds of problems).

 

@techknight Does this mean you're no longer "on hiatus"?

 

c

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On 3/28/2021 at 5:45 AM, CC_333 said:

Reading this discussion makes me glad I don't have a non-backlit Portable (I was lucky to have managed to find the somewhat less common backlit model, which has a different logic board design that doesn't seem to have these kinds of problems).

 

@techknight Does this mean you're no longer "on hiatus"?

 

c

 

I kind-of am, but i am not at the same time. Hard to explain. 

 

Anyways. Maybe i should re-design the portable like the other guys did with the SE, and SE/30? Hmm.... would take alot of work and time I don't have right now, though. 

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20 hours ago, techknight said:

 

I kind-of am, but i am not at the same time. Hard to explain. 

 

Anyways. Maybe i should re-design the portable like the other guys did with the SE, and SE/30? Hmm.... would take alot of work and time I don't have right now, though. 

Do we need to reproduce the exact function of the pwrmgr? wonder if its possible to do a new version with different functionality but makes the board work hah. 

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21 hours ago, techknight said:

I kind-of am, but i am not at the same time. Hard to explain. 

 

Anyways. Maybe i should re-design the portable like the other guys did with the SE, and SE/30? Hmm.... would take alot of work and time I don't have right now, though. 

 

A makeover of the 5120 board will be awesome when you get enough time for the project. In the meantime, what I'd like to see you play around with would be a generic interface board for the LCD. Then Bolle's SE/30 board could be adapted to fit the Portable form factor using the 12V input ATX power supply developed for the LC? No longer battery Portable, but lots of fun to be had with existing building blocks while you work out a way to knit together the 5120's proprietary parts? Rebuilding those will be crazy complicated, no?

 

20 hours ago, Amiga of Rochester said:

Do we need to reproduce the exact function of the pwrmgr? wonder if its possible to do a new version with different functionality but makes the board work hah. 

 

Following your topic closely, I like your notion there. Isolating the board from the power system for troubleshooting makes a world of sense to me. Would you need to replace the Power Manager entirely or fool it into thinking the battery is charged and the AC adapter plugged in while it remains in place? That LC PSU replacement might make a workable replacement for a bench supply for those of us who have a couple of 5120 boards to troubleshoot?

 

Edited by Trash80toHP_Mini
apparently I can no longer type/spell.
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21 hours ago, Amiga of Rochester said:

Do we need to reproduce the exact function of the pwrmgr? wonder if its possible to do a new version with different functionality but makes the board work hah. 

 

I think @androda is working on reverse-engineering the backlit version of the power regulators since they are completely different. We might be able to bring that design forward, but we will have to see. 

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Posted (edited)

Yes, I've spent some time on this.  While I was replacing the capacitors on a backlit portable I managed to find the time to buzz out a bunch of the backlit's hybrid replacement.  The results are documented here: https://68kmla.org/forums/topic/62148-new-hybrids-for-the-macintosh-portable-m5120/?do=findComment&comment=666493

 

That board has gone back to its owner (working, yay) and since I don't own one myself the effort has stalled for the moment.  @techknight has offered to sell me some of his old parted out backlit boards to continue the effort, so I can get back to it after we figure that out.

 

Goals are basically to finish buzzing it out and cataloguing resistor values (we are missing several).  Looking at the current trace, there are some basic mosfet switches that are reasonably easy to understand.  The op-amp stuff is where all the real magic happens and that'll take more doing to grok.

 

The ideal is to replace all the linear regulators and opamp magic with modern buck regulators and a little microcontroller.  Micro can turn on and off the 12v, 5v drive power, and -5 volt stuff while also having an A/D line signaling out to the power manager.  This will clearly take more work on the individual units when doing the modification, but if you're already removing a big module to replace it, why not go the rest of the way by removing some other components here and there?  Mostly it'll be the big IRF9z30s that go, along with a few other smaller things.

 

And none of this will happen until I'm done working on the BlueSCSI variant boards I've designed for powerbook and mac portable.  What's life without a project list which is a mile long?  :)

Edited by androda
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19 hours ago, androda said:

Yes, I've spent some time on this.  While I was replacing the capacitors on a backlit portable I managed to find the time to buzz out a bunch of the backlit's hybrid replacement.  The results are documented here: https://68kmla.org/forums/topic/62148-new-hybrids-for-the-macintosh-portable-m5120/?do=findComment&comment=666493

 

That board has gone back to its owner (working, yay) and since I don't own one myself the effort has stalled for the moment.  @techknight has offered to sell me some of his old parted out backlit boards to continue the effort, so I can get back to it after we figure that out.

 

Goals are basically to finish buzzing it out and cataloguing resistor values (we are missing several).  Looking at the current trace, there are some basic mosfet switches that are reasonably easy to understand.  The op-amp stuff is where all the real magic happens and that'll take more doing to grok.

 

The ideal is to replace all the linear regulators and opamp magic with modern buck regulators and a little microcontroller.  Micro can turn on and off the 12v, 5v drive power, and -5 volt stuff while also having an A/D line signaling out to the power manager.  This will clearly take more work on the individual units when doing the modification, but if you're already removing a big module to replace it, why not go the rest of the way by removing some other components here and there?  Mostly it'll be the big IRF9z30s that go, along with a few other smaller things.

 

And none of this will happen until I'm done working on the BlueSCSI variant boards I've designed for powerbook and mac portable.  What's life without a project list which is a mile long?  :)

I won't lie, I probably won't take on many more Portables. I just fixed the classic I mentioned above. I agree with the idea of replacing the whole hybrid, how I'd approach it. I hope one day to offer this service to people, but it seems far off.

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On 3/28/2021 at 12:26 PM, techknight said:

I kind-of am, but i am not at the same time. Hard to explain.

No explanation needed.  I think I understand-- you're in some sort of transitional period, where you're beginning to feel a spark of interest in the hobby again, but you don't yet have the time (or the motivation) to devote much effort to it.

 

c

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22 hours ago, CC_333 said:

No explanation needed.  I think I understand-- you're in some sort of transitional period, where you're beginning to feel a spark of interest in the hobby again, but you don't yet have the time (or the motivation) to devote much effort to it.

 

c

 

Well not only that, but im trying to recover from some serious depression that i have been going through the last few years. 

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19 hours ago, techknight said:

 

Well not only that, but im trying to recover from some serious depression that i have been going through the last few years. 

 

Been there, @techknight Let us know how we can help cover your back. We're on your side!

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19 hours ago, ScutBoy said:

 

Been there, @techknight Let us know how we can help cover your back. We're on your side!

 

Thanks for the thoughts! Yeah, I wish I knew... but i dont. For me, its just time... which isnt helping a whole lot. but its getting better, i think? 

 

I just have no motivation to do anything in life. just sitting and spinning my wheels. Eventually I want to become a homeowner, but with the market the way it is, i just dont see it happening any time soon. 

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