Macintosh Portables Dead

[North Hedge Ned]

Hello, I know that there is much discussion around the Mac Portables and their woes with powering up.  So much information, in fact, that I have become lost in it all and have no idea where to start.  So, if I may, some simple questions, and some directional guidance required.

I have several of these beasties and they all do not seem to start up.  Some don't boot at all, some boot then power off, some boot, show a mouse, and the drive tries to spin up then shuts off.  One I had boot and went straight to sad Mac.  It even ran off the replacement battery that I had in it (6v 5maAh lead-acid, new, fully charged), in this sad Mac state.  However when I disconnected power and tried again, it would not boot.

I always had the cutoff switch engaged when trying to boot from the main battery.

With adapter connected (a real Portable Adapter) I am getting the 7.1 v reading at the main terminals inside the computer with the cutoff engaged.  With my battery connected, I get the same.  When I activate the cutoff (as in have the switch open) and my battery connected, I am reading the 6.3v of the connected battery at the terminals.

Questions:

1.   Must the 9V battery be installed for the unit to function properly?

2.  If I were to pul the board, is there a concise step by step with photos of how and what to test with my multi-meter?  Would this resource also tell me what to replace and how?  I do not have the means to remove old solder.

Looking for guidance and a resource to dive into.  I ultimately wish to sell these things, and suspect that the cost to fix is more than recovered by the sale of a functional unit vs a dead one.

Thank you all in advance!

Paul

 

[LaPorta]

Paul,

i am am not certain what you mean by “it even ran off the replacement battery” - All Portables MUST run off their battery. The power adapter is only used to charge it. 

Second, are you 100% sure it is a battery that is good for a Portable? The thing shutting down with HD spin up sounds like too much of a current draw on the battery. Certain batteries can only deliver so much current at a time, despite voltage rating (witness an “only” 12 volt car battery turn over that huge motor - much current is supplied instantly). I had a 6V for my Portable that didn’t work, and only once I got a proper replacement was it good.

Third, did you re-cap the board?

Photos would also be helpful.

 

[North Hedge Ned]

Thanks LaPorta,

“it even ran off the replacement battery” - by this I mean that the unit continued to be powered when I unplugged the AC adapter.  In the unit I was running my 6V battery.

I think that this batter is good.  6v 5mAh, same kind in my kid's electric ride'em car.  In fact, here is the Amazon link:  https://www.amazon.ca/dp/B00NR5NGRE/ref=cm_sw_em_r_mt_dp_U_QIU3Cb4KCR4R3

Third - I have not recapped.  I know about it, but I have not found a concise "how to" and what parts to use, and where to get them.

Any ideas?

Thanks

 

[MOS8_030]

Yes, the Portable needs a good 9V battery to be installed.

I use this lead-acid battery. It will fit inside the portable, and trimmed down a bit can be fitted into the original battery case.

Although theoretically the battery you have should work as well.

It is likely your Portable will need to be recapped to some extent.

If you do a forum search you'll find several threads relating to recapping Portables and there are several members here with specific Portable experience.

Perhaps they'll participate in this thread.

 

[LaPorta]

Looked at the specs of your battery, it had the same issue the first I used did: fairly low initial max discharge current. The above battery MOS used, and the one that I used down here:

https://www.batteriesplus.com/battery/sla-sealed-lead-acid/6/hawk0809=0012

Are better suited for the Portable.

As for the capacitors, I made a list I can get to you from home when I get there.

 

[MOS8_030]

Looked at the specs of your battery, it had the same issue the first I used did: fairly low initial max discharge current.

Ah, good point.

Also I see the price has gone up since I purchased mine.

(It's 20 years old and long dead.)

 

[LaPorta]

Oh I didn't mean yours: your battery was probably a great replacement, I meant the one that he initially had used at the start of the thread.

 

[MOS8_030]

Oh I didn't mean yours: your battery was probably a great replacement, I meant the one that he initially had used at the start of the thread.

Yes, I understood that.

I meant you're probably right about his battery.

 

[LaPorta]

Here are the Portable capacitors, per my hand-written notes at home:

Portable Capacitors:

C2 - 100µf, 25V - Radial

C3 - 220µf, 25V - Radial

C4 - 1µf, 50 V - Surface Mount

C5 - 1µf, 50V - Surface Mount

C6 - 100 µf, 25V - Radial

C8 - 470µf, 25V - Axial

C9 - 47µf, 16V - Surface Mount

C10 - 47µf, 16V - Surface Mount

C11 - 47µf, 16V - Surface Mount

C14 - 10µf, 16V - Surface Mount

C15 - 1µf, 50V - Surface Mount

C16 - 470µf, 25V - Axial

C17 - 47µf, 16V - Surface Mount

C18 - 100µf, 25V - Radial

C19 - 100µf, 25V - Radial

C20 -  470µf, 25V - Axial

C22 - 47µu, 16V - Surface Mount

C24 - 1µf, 50V - Surface Mount

C25 - 47µf, 16V - Surface Mount

C26 - 47µf, 16V - Surface Mount

C27 - 47µf, 16V - Surface Mount

C28 - 47µf, 16V - Surface Mount

C116 - 10µf, 16V - Surface Mount

Capacitors behind the LCD:

C11 - 220µf, 10V - Radial

C23 - 10µf, 16V - Radial

 

[Bolle]

You are going to have to strip out the logicboard and hook up the battery terminals to a bench powersupply (you have to do this the correct way or you are going to kill components on the board) to be able to do any useful troubleshooting.

Replacing the caps and cleaning the board really good is obligatory before any further troubleshooting can take place.

Look up techknights youtube videos on the Portable. They are a very good starting point.

Check for broken traces around the Hybrid and in all places where caps are sitting. It’s common that stuff breaks around there.

 

[North Hedge Ned]

Thank you all for your input - it certainly gives me a lot to test and attempt to solve.  Thanks again.  Will post my findings and success if you are at all interested.  One of the units is a pre-release unit so that may be my first one to work on.  It has a serial number, but a big bold sticker inlace of the usual label that states that the unit is a demonstration unit only and final release product will meet the FCC codes.  When I get a glimpse of it inside would you be interested in posts along the way?  Cheers!

 

[LaPorta]

Two things:

1. Absolutely would love to see your progress! Please keep us updated.

2. I'd first work on one of the others. Why potentially bungle a prototype while learning?