Mac Portable Hybrid: combine forces?

[LaPorta]

I had a thought the other day: all of us non-backlit portable people live in fear of our Hybrid dying someday and rendering our Portables useless. Rumor has it that @techknight once said that he would want to reverse engineer one, but that he would need to sacrifice one to do it. No one wants to sacrifice their own Portable, of course.

So my thought was: what if a few of us pooled resources? Imagine a theoretical eBay Portable for $500. Five people could pool $100 each, or ten $50 each, and then donate it to have the hybrid hacked, duplicated, and give us all a way to keep these machines going.

What’s everyone else think?

 

[mg.man]

Question... @techknight, does it need to be a working 'board that gets sacrificed?

 

[Johnnya101]

Question... @techknight, does it need to be a working 'board that gets sacrificed?

Yes, well, the hybrid needs to be in perfect shape. If the boards junk but hybrid good I think that's all that matters.

I was kind of planning on donating a hybrid once I get a portable on exchange for a new one, but I like the idea of pooling money together better. The thing is, is you need a known good one. Any old untested one for $500 is a huge risk because who knows if it will have a good hybrid or not.

Techknight, do they just "work" and that means they retain factory values for components/the weird carbon etched resistive traces or whatever it uses, or do you need an absolutely perfect one with low hours or something?

 

[LaPorta]

There’s a candidate here:

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[techknight]

It is already being worked on and basically functional.

@androda has the lead here

We haven't said anything about it publicly yet because its still very much a device-under-test. But, so far the 5.2V regulator is operating at around 5.6V, and he forgot a trace so he has to update the board layout.

The first version is made with potentiometers for adjusting precision due to the fact that most of the "non functional" hybrids have altered resistor values.

There have been a couple changes to the design to try and make them more efficient than the original, plus there are component supply issues currently as well. I don't know any more details than that at this time.

He is also currently working on a replacement backlit LCD cable.

 

[ScutBoy]

It is already being worked on and basically functional.

...

He is also currently working on a replacement backlit LCD cable.

A hard "like" on this news!

 

[Johnnya101]

Great to hear, I'll definitely buy a couple to have on hand when they are ready

 

[LaPorta]

Happy to hear this news! Thanks for sharing!

 

[desertrout]

Holy cow... I came here to say I would be interested in supporting @LaPorta 's plan, but SUPER cool to hear this is already under way!

 

[androda]

Yes, this project has been in progress for a little while now. The prototyping PCBs (with holes for resistors instead of SMD pads) were made last month, and finally found time to put them together last week.

I went a little overboard and made a two-PCB system. There's the hybrid PCB with same schematic as original (except for that missed trace which is now fixed in the design). And the second PCB is what I call the 'downstream' board, which has the same mosfets, capacitors, and hookups as a real portable. This way I can muck around with resistor values on the hybrid with no fear of destroying a real portable's electronics.

Like @techknight said, the main 5v rail was running at 5.6v but that has been fixed by updating the value of one particular resistor. Now it's at 5.25v.

Things which are working: Main 5v rail, 12v enable, -5v enable, battery charger, battery charge indicator signal (signal to the power manager chip), battery charge cutoff (HICHG).
Things still to be figured out or tested: -5v rail (running at -6 volts for some reason), under-voltage lockout, A/D feedback line voltages, and the final testing in a real portable.

 

[mg.man]

Awesome stuff! Can't wait -- certainly down for a couple of these!

 

[techknight]

Turns out the -5V issue was caused by bad chips from a supplier overseas (big shocker)

those chips are expensive too, so I think the circuit will be re-engineered to choose a different part for -5V inverter rail generation.

 

[Trash80toHP_Mini]

Was wondering when you'd make an appearance here, tk. You've been looking at that critter for years now. @androda thanks for taking the lead. Pushing the envelope outside the the box by adding that second board for diagnostics was brilliant.

 

[techknight]

I just got his re-created Backlit LCD cable. ill be trying that this weekend i think.

 

[Siliconinsider]

Big question, as I currently have a Macintosh Portable from a friend that is suffering from a bad hybrid (it has taken a toll of some chips in the audio section, and the 5V rail is looking absolutely horrible with spikes up to VBAT). It seems the hybrid does not do much, other than generating the +5V and -5V rail, as well as some very basic control signals. Why not simply replace all these obsolete analog chips with a modern DC/DC converter instead of trying to make a replica? I have bypassed the hybrid entirely here by feeding 5V straight to the drain of Q16 (red clip) and the mac works very well. Q14/Q15 are in parallel, feeding the LT1070 that generates the 12V rail (outside of the hybrid), which should get the hard drive going.

Sick 5V rail:


Powering the portable straight from 5V, bypassing the hybrid entirely

 

[mg.man]

I have bypassed the hybrid entirely here by feeding 5V straight to the drain of Q16 (red clip) and the mac works very well

Fascinating... I have a sickly Portable that might be worth giving this a shot... @joshc, you might also be interested?

It seems the hybrid does not do much

But doesn't the Hybrid handle the (lead acid) battery charging?

 

[alectrona2988]

don't know too much about the portable (although i do have a powerbook 145b that is broken) but you know those IPS kits for old gameboys? i feel like someone could probably make some for the macintosh portable and maybe some old powerbooks

 

[Siliconinsider]

But doesn't the Hybrid handle the (lead acid) battery charging?

I have to look at the schematics in more details but I don't think it does.

 

[Trash80toHP_Mini]

That running the Portable in the old, received wisdom (idiocy in this case) no battery/higher output AC Adapter state has killed so many Portables I'm wondering about that? @techknight what components would be at risk of being taken down in said catastrophic failure? IIRC Hybrid would be the primary point of failure?

 

[alectrona2988]

All these ancient computers and their wacko power components... LOL