Mac Portable Mystery...

[EspiritLaguna89]

Hi all, first time poster and Macintosh Portable owner here! I've always wanted one of these beautiful machines and finally was able to get one with a rebuilt battery in lovely shape. Caps are leaky so I will definitely have to get them replaced as the machine doesn't like booting up (sometimes it starts and shuts down due to 'low battery', sometimes it just glitches out the startup chime). But in the meantime, I have a mystery with this machine;

As you can hopefully see in the photos, this machine doesn't have the usual markings on the information sticker, instead a disclosure that the device is for demonstration and not a retail unit. The serial number, F9344GGM59, is also unusual as I don't recall seeing GGM in other serial numbers... Other things I'm not sure are common or not are the REV D indication on the keyboard, stickers on the board that say 'Mac Test 1' and 'Test 1', and the number on the logic board. If anyone has any clues as to what this machine is, I'm all ears!

 

[3lectr1cPPC]

I can tell you one thing, that board has already been recapped! Not sure about the non-surface mount caps, but the surface mount caps have been replaced with tantalum caps! They look really clean too.

The symptoms you describe sound like a failing HYBRID IC. You can source a new one here: https://androda.work/product/macintosh-portable-hybrid-module-recreation/

Edit: Compared to the board photo on my website, the radial and axial caps appear to be new as well. That board is fully recapped. I do still see some corrosion around the U1M HYBRID IC though, which had likely caused it to fail. They're super susceptible to corrosion.
Non-recapped board image for reference: https://macdat.net/cap_reference/apple/powerbook/portablem5120.html

 

[EspiritLaguna89]

I can tell you one thing, that board has already been recapped! Not sure about the non-surface mount caps, but the surface mount caps have been replaced with tantalum caps! They look really clean too.

The symptoms you describe sound like a failing HYBRID IC. You can source a new one here: https://androda.work/product/macintosh-portable-hybrid-module-recreation/

Edit: Compared to the board photo on my website, the radial and axial caps appear to be new as well. That board is fully recapped. I do still see some corrosion around the U1M HYBRID IC though, which had likely caused it to fail. They're super susceptible to corrosion.
Non-recapped board image for reference: https://macdat.net/cap_reference/apple/powerbook/portablem5120.html

Interesting, thanks for the info! I've attached some close up photos of the board where I saw what looked like leakage, and the corrosion you mentioned on the U1M HYBRID. Do you think that would be repairable? The full explanation of symptoms is when I initially plugged in and got the battery to charge (it's rebuilt so I know it's good, also used a bench supply to make sure it charged correctly) the machine would boot and immediately throw the no reserve battery warning, then shut down. Perhaps foolishly, I let it charge overnight and now in the morning it doesn't want to boot either. The chime plays, but is distorted and keeps repeating while scrambled images show on the display. I hope I haven't broken anything further, though the board was definitely going to need work regardless...

 

[Phipli]

ve attached some close up photos of the board where I saw what looked like leakage,

That isn't leakage, just someone not bothering to clean the board hugely after soldering. Just wipe it down with some IPA.

That type of capacitor doesn't contain liquid, they have nothing to leak, which is why someone fitted them.

Edit : actually, it is a coating someone applied after doing their work. Some kind if clear enamel type thing. Nail varnish or a PCB lacquer. It's fine as it is. They've done a good job.

 

[EspiritLaguna89]

That isn't leakage, just someone not bothering to clean the board hugely after soldering. Just wipe it down with some IPA.

That type of capacitor doesn't contain liquid, they have nothing to leak, which is why someone fitted them.

Edit : actually, it is a coating someone applied after doing their work. Some kind if clear enamel type thing. Nail varnish or a PCB lacquer. It's fine as it is. They've done a good job.

Good to know! That saves me some trouble haha, any idea what could be causing the boot issues?

 

[Phipli]

Good to know! That saves me some trouble haha, any idea what could be causing the boot issues?

I don't know Portables sorry, but 3lectr1cPPC has given some suggestions.

I believe they need a good battery though. Perhaps that is the first thing to sort.

 

[3lectr1cPPC]

The hybrid module has a good bit of oxidization on it, thats likely to be your issue. That rust spot appears to be a that metal area around the screw hole and no further, so that’s likely fine. The leakage you appear to see is either going to be flux left on the board from the guy who recapped it I’d guess. Should be repairable. Make sure you’re using a recapped PSU too, and that it’s a portable PSU and not a gray PowerBook charger. The PowerBook supplies will blow the charging mosfet on the portable.

 

[EspiritLaguna89]

The hybrid module has a good bit of oxidization on it, thats likely to be your issue. That rust spot appears to be a that metal area around the screw hole and no further, so that’s likely fine. The leakage you appear to see is either going to be flux left on the board from the guy who recapped it I’d guess. Should be repairable. Make sure you’re using a recapped PSU too, and that it’s a portable PSU and not a gray PowerBook charger. The PowerBook supplies will blow the charging mosfet on the portable.

Yep, I'm using a portable charger, which seems to be working properly per multimeter readings. I'll look into the Hybrid module. Any voltage readings I should be watching out for to indicate that it's faulty?

 

[EspiritLaguna89]

The hybrid module has a good bit of oxidization on it, thats likely to be your issue. That rust spot appears to be a that metal area around the screw hole and no further, so that’s likely fine. The leakage you appear to see is either going to be flux left on the board from the guy who recapped it I’d guess. Should be repairable. Make sure you’re using a recapped PSU too, and that it’s a portable PSU and not a gray PowerBook charger. The PowerBook supplies will blow the charging mosfet on the portable.

Yep, I'm using a portable charger, which seems to be working properly per multimeter readings.

 

[LaPorta]

What battery do you have?

 

[EspiritLaguna89]

What battery do you have?

It's a rebuilt battery, the previous owner wired the original shell to an ExpertPower EXP650 6V5ah lead acid battery