Just purchased M5126 HELP

[Gary119]

Hello everyone, I apologize ahead of time if I posted this in the wrong forum. This is my first post. To make a long story short, I just bought my first Apple computer I’ve ever owned. It’s a Macintosh Portable M5126. I took it apart the other day to inspect the main board. I know the capacitors all need replacing, but I discovered other areas of concern. On the bottom side of the main board, I discovered deterioration to a substantial amount of traces. I’ve attached photos of the more prominent areas. My question is, could this be surface tarnish, or are these traces completely gone? Any help is GREATLY appreciated. I’ve got a history in cleaning and maintaining game systems, but I’ve never taken on a repair task like this before. Hope to hear from you all soon, thanks.

I want to bring this computer back to life.

Gary.

 

[360alaska]

Actually, Those are probably mostly okay. But mostly okay is like mostly peaceful, you're probably going to have at least problem trace. I suggest to go ahead and recap it and see if it works, it may in fact work. Who knows? Case in point, I had a SE/30 board I bought on ebay that wouldn't boot because one trace was open by the width of a human hair.

 

[Gary119]

Actually, Those are probably mostly okay. But mostly okay is like mostly peaceful, you're probably going to have at least trace. I suggest to go ahead and recap it and see if it works, it may in fact work. Who knows? Case in point, I had a SE/30 board I bought on ebay that wouldn't boot because one trace was open by the width of a human hair.

Thanks so much for the response! I’m ordering all replacement electrolytic capacitors. What’s the best way to test continuity on the traces, to ensure which ones are not broken?

 

[360alaska]

Well, the schematics are available: https://drive.google.com/drive/folders/0B_Xp3uN-BcxsQjFLRUZqeEw2VFE?usp=sharing

But mostly if I suspect a bad trace I'll uncover both ends by gently scraping or sanding the surface to reveal the copper and then test continuity. But I'd suggest waiting for your caps and then checking it after. You'll also need working battery for it to boot.

 

[Gary119]

Well, the schematics are available: https://drive.google.com/drive/folders/0B_Xp3uN-BcxsQjFLRUZqeEw2VFE?usp=sharing

But mostly if I suspect a bad trace I'll uncover both ends by gently scraping or sanding the surface to reveal the copper and then test continuity. But I'd suggest waiting for your caps and then checking it after. You'll also need working battery for it to boot.

Got the through hole axial caps in the mail, the leads are too large and won’t fit through the holes on the board. I measured the original cap lead size, which was 0.65 mm. The ones I got in the mail are 0.80 mm. Does anyone know where to get ones that will fit? 

 

[360alaska]

Digikey or EBay is probably your best bet.

 

[Gary119]

Hello again, 

Since we last chatted, I have since cleaned and recapped the logic board for my M5126. Upon reassembly I confirmed that the battery plug was reading proper voltage to the point that it plugs into the logic board. I tried to boot the system, but It does nothing, as if no power is present. I have looked at the schematics link you previously sent, do you have a link for a backlit M5126 schematics sheet, or perhaps insight on what the problem may be?

Thanks.

 

[ScutBoy]

With the main battery, the 9 volt battery, and the _correct_ A/C adapter all plugged in, hold both the reset and interrupt switches in for 10-20 seconds and see if it will boot when you release.

This has helped with my Portable. Good luck - these can be tempermental...

 

[Gary119]

With the main battery, the 9 volt battery, and the _correct_ A/C adapter all plugged in, hold both the reset and interrupt switches in for 10-20 seconds and see if it will boot when you release.

This has helped with my Portable. Good luck - these can be tempermental...

I am using a 6.4 volt battery as a replacement, per other people’s recommendation. I do not have an AC adapter for the computer. I also have a 9 volt battery in place as well. When I hold both the reset and interrupt buttons for that time period, I release and hit a key to boot the unit, but it does nothing.

 

[LaPorta]

From the amount of crud on the board, you may have more rotten traces than you know. @techknight is the expert in this area with these machines.

 

[ScutBoy]

I am using a 6.4 volt battery as a replacement, per other people’s recommendation. I do not have an AC adapter for the computer. I also have a 9 volt battery in place as well. When I hold both the reset and interrupt buttons for that time period, I release and hit a key to boot the unit, but it does nothing.

Sorry it didn't help. I know it resets the power manager (or similar) and has helped my machine when it's been acting up.

 

[techknight]

I dont really have any additional input right now because it could literally be anything. 

if its not turning on, it could be some damaged traces or connections right there at the circuit behind the two side reset/nmi buttons. 

Sometimes it can be the PMGR. it could literally be anything. 

 

[Gary119]

Thank you very much for the response