Recreating Macintosh Portable Hybrid Module

TimoB

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Jul 11, 2022
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Would a DIL socket work that's soldered in place of the old hybrid, into which the replacement part can be plugged in? I'm not sure about the dimensions, i.e. if the pin spacing is the standard 2.54mm grid. Then a standard socket might fit and the counterpart on the new hybrid could be essentially the same but with the pins sticking out from the bottom.
Height shouldn't be an issue?
 

Androda

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The pin spacing is standard 2.54mm. Was worried about that at first because they could have easily done something totally custom. But the mounting holes are for machine pin headers, not standard ones. I have a machine pin socket installed on a portable for testing, and exerting force properly to remove the hybrid without damaging the pins is difficult because of how thin the legs are.

My tester PCB has a standard socket on it, but doesn't contact the legs well enough to be reliable because of the machine pin legs being thinner.
 

TimoB

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Jul 11, 2022
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Got it. I bought a bag of 1x40 PCB connectors (male and female) a while ago. Solder side on the female ones looks quite thin, I'll test if I can fit it in; my Portables hybrid is totally shot anyway so I'll be happy to experiment.
 

TimoB

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Jul 11, 2022
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Did some measurements today - I think the part I had in mind won't fit - there is 13mm space between PCB and the silver painted plastic where the hybrid sits. The part I had in mind is 11mm tall (female + male connector) which leaves only 2mm for the new hybrid PCB + components. Would have to find out if there's something similar available in "half-height"
 

Androda

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PCBs arrived early, so I assembled and tested one this morning. It passed testing both on the dedicated test PCB and in a test Portable, which gives me pretty high confidence that it's going to work in general.

These will probably not be listed and available for sale until after the conference next week, but I can probably get a few (maybe four) done and out the door to early testers. Please DM me (again, if necessary) if you are interested. I would like two testers that are USA based, so that these can get to you sooner than later without having to pay an arm and a leg in shipping cost. (Note: non-US-based testers are fine too, just looking for faster feedback without high shipping cost)

To anyone that wants an "unassembled kit", I'm sorry. These are going to be SMD-assembled or fully-assembled only. Cutting and labeling each and every custom resistor value (there are like 9, and several of them are completely unmarked) would take as long as just doing the SMD assembly, meaning that I'd have to charge the same price. Funny how that works.

Long term plan is to release the full design and parts list under my usual CC-NC license in a few months, so it doesn't get lost to time.
 

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Androda

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There have been some questions about PCB color for the later production modules. I lean toward green, but can understand that people might want something closer to the original color (blue).

What do people think?

1659559488707.png
 

TimoB

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Jul 11, 2022
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I‘m fine with any color, after all it‘s nothing thats visible from the outside. If originality is a concern, then one would have to find an original Apple spare part anyway - good luck.
 

Androda

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Two hybrid recreations have been claimed by some of our friends in Europe, leaving two available for USA-based testers. DM me if interested.
 

Garrett

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I have a couple portable boards that don't boot, but I haven't done any deep exploration into whether the hybrid is to blame... I better let someone with a known bad hybrid take a shot at these wonderful recreations!
 

Androda

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I have a couple portable boards that don't boot, but I haven't done any deep exploration into whether the hybrid is to blame... I better let someone with a known bad hybrid take a shot at these wonderful recreations!
Generally speaking, the hybrid and power manager are the cause of a lot of issues. There are plenty of other options though, like corroded traces to RAM and other things.
 

JustG

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Dec 12, 2021
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Same boat as Garrett, I have a Portable that needs some help, I'll snag one or two of these boards once people who can do proper testing have a whack.
 

Androda

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Feedback from testers is that the A/D line isn't exactly like the original. Boots and works fine, but the battery meter might only go to 6 or 7 out of 8 bars on the gauge. Fortunately, this isn't a huge issue - I could add a little trimmer potentiometer to the board for people that want it to show completely full, or even just an optional resistor pad.

If you are testing your Portable with a power supply to the battery contacts (all 4 pins need contact), you will need a minimum of 3 amps at 6.4-ish volts to boot from a floppy drive, and probably 4 to 5 amps to boot from a hard drive. Use of a bluescsi will cut that significantly, high current draw is from the 12 volt boost converter.

I'll be assembling a few more of these early boards over the weekend, and will poke around to see if there's a good option for a trimmer resistor.
 
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Androda

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Two very interesting things have emerged about the Mac Portable and the Power Manager chip, based on my increased understanding of the Hybrid module through all this research and work.

1: The A/D line voltage, intended to convey battery and charge level information to your system, can kill your power manager chip

First, I present the voltage tolerance section of the original power manager chip datasheet, a Mitsubishi M50753.

1663326628949.png


These 'absolute maximum' statements tend to be pretty accurate, and running outside these ranges will cause chip damage.

The A/D input pin of the power manager is in the "IN" bank of the chip, third row down from the top (not including the headers). Its maximum allowable input voltage is the chip's Vcc (main power) plus 0.3 volts.

Have you ever wondered why the main 5 volt power rail of the mac Portable is 5.2 volts instead of, you know, 5? I think this is part of the reason. This "IN" port can accept voltages up to 5.5 before there's a real problem. And because these are absolute max values, you really want to stay under 5.5, if not near 5 volts to be completely safe. The A/D line on some portables I've measured runs up to about 4.7 volts.

So, you ask, where's the problem? We're safely under the 5.5 volt absolute max.

Well, actually that's not guaranteed. The opamp Vcc (power input) determines how high the output can swing. And this can range most of the way up to battery terminal voltage. See where this is going? Drifting resistors on the hybrid from a variety of causes will change the A/D output multiplier and definitely can swing that high. After replacing the capacitors on my friend's Portable, I tested the A/D voltage and found it spiking to 6.2 volts when plugged in. That's a clearly dangerous voltage knowing what we do about the power manger chip's input voltage limitation.

On to #2, what else is in the A/D circuit which could help mitigate this issue?
Check out the Portable schematic. On page 12 we find a current limiting resistor on the A/D line before it goes to the power manager chip, highlighted in red. Next to it is a little capacitor to ground, forming an R-C network which basically smooths out any big spikes in the A/D line voltage.
1663327509626.png


This little R-C network probably doesn't provide much protection. Voltage at the "A/D Filter" pin on the power manager will still go too high if your hybrid is putting out more than 5.5 volts. The little 1k resistor is a current limiter at least.

I suggest that everyone with a working Portable should check if the A/D voltage is too high when charging the battery (also check on-battery use). If your A/D voltage ever heads above 5.5 volts your system is probably in danger.

A solution would be to stick a 5v zener diode on the C107-side of R151 to clamp it and prevent damage to the power manager from an A/D line which is running too high. And an A/D line running too high is a good indication that your hybrid is degrading, so you should check the other voltage rails to see if things are still in spec.
 

Androda

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Also, a status update. I have redesigned my "downstream" tester board a bit, and hope to have the updated version by the end of next week. This will be set up with pogo pins as a fixture for use in starting production of these hybrid recreation boards.

The pogo pin tester will allow me to run whatever tests are necessary to verify each individual recreation board's functionality before shipping out. Battery charging, discharging, A/D voltages, undervolt lockout, this will let me test it all.
 

Androda

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Say hello to the 'integrated hybrid tester platform'.
Includes three dedicated little voltage meters for (top to bottom) battery, A/D line, and the main 5.2v rail. Three switches are also on there for enabling/disabling 12v, -5v, and the "hichg" line.
All hybrids will be tested on this for their basic functions before shipping out.

In the next week or two I hope to write up a document on "what to check on your mac portable" before ordering one of these to replace the original. There are some components around the hybrid that can affect functionality, and you need to be sure that connections are not corroded. So it'll be a visual guide showing how to check what is connected to where, and with what kind of resistance.
 

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techknight

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Say hello to the 'integrated hybrid tester platform'.
Includes three dedicated little voltage meters for (top to bottom) battery, A/D line, and the main 5.2v rail. Three switches are also on there for enabling/disabling 12v, -5v, and the "hichg" line.
All hybrids will be tested on this for their basic functions before shipping out.

In the next week or two I hope to write up a document on "what to check on your mac portable" before ordering one of these to replace the original. There are some components around the hybrid that can affect functionality, and you need to be sure that connections are not corroded. So it'll be a visual guide showing how to check what is connected to where, and with what kind of resistance.

Holy contraption batman
 
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Androda

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Production has started on the hybrid recreation PCBs, version 2 (adjustable A/D line output).
Once these are done and tested I plan to open up the listing. I'm using this version in one of my Portables, and the previous version (without adjustable A/D line) in another one.
 

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