1. Home
  2. Hobby Electronics Basics
  3. MacBook 13" charger circuit

MacBook 13" charger circuit

I have a MacBook 13" (not under warranty). When the charger is connected it does not light or charge the battery. I have tested the battery and charger on another MacBook and they are fine. I have reset PRAM and SMC. Cleaned both the charger contacts and the ones on the computer.

Occasionally if I leave the charger connected to the computer for several minutes I get a faint flickering light (I cant even really tell if the light is green or orange or sort of both colors combined)

I am reading dual voltages at random spots in the laptop with the AC charger connected.

My guess is that something has burnt out on the main logic board. I have the computer open and have found one fuse (F 790) that is in tact.

Can someone with a service manual give me some test points and possible components (voltages, etc) to check.

Thanks

Reply to
Jack B. Pollack
Loading thread data ...

I strongly doubt there is one - Apple services these machines at the subassembly level. Suggest you do a comparative, since you have a second machine available.

Also, I have encountered odd charging issues where the machine was otherwise working OK when the MagSafe contacts were dirty. Make sure you clean those too!

Reply to
zwsdotcom

I strongly doubt there is one - Apple services these machines at the subassembly level. Suggest you do a comparative, since you have a second machine available.

Also, I have encountered odd charging issues where the machine was otherwise working OK when the MagSafe contacts were dirty. Make sure you clean those too!

Thanks for your post.

The other machine is not mine so I can't really disassemble it. Just tried re-cleaning the contacts, didn't help.

Reply to
Jack B. Pollack

Sometimes removing the battery and powering up from the charger works to reset something. I haven't a clue why but its worked a couple of times for me on a Dell and a HP machine. HTH.

--
Best Regards:
                     Baron.
Reply to
Baron

Thanks. didn't help

Reply to
Jack B. Pollack

Jack B. Pollack Inscribed thus:

Sorry about that ! Just a guess... Could there be a magnetically operated switch behind the connector.

--
Best Regards:
                        Baron.
Reply to
Baron

I assume you've been over the board with a fine-tooth comb looking for possible dry solder joints or cracked copper, particularly in the vicinity of the battery connector and charger input?

With the battery connected, what happens to Vbat when you connect the charger - does it jump up (might take a couple of seconds) or does it suddenly go to a sawtooth waveform, or what?

What happens on the other lines to the battery - do you see a bidirectional I2C transaction taking place?

Reply to
zwsdotcom

I assume you've been over the board with a fine-tooth comb looking for possible dry solder joints or cracked copper, particularly in the vicinity of the battery connector and charger input?

With the battery connected, what happens to Vbat when you connect the charger - does it jump up (might take a couple of seconds) or does it suddenly go to a sawtooth waveform, or what?

What happens on the other lines to the battery - do you see a bidirectional I2C transaction taking place?

I check this stuff over the weekend.

I dont under stand this??

Thanks

Reply to
Jack B. Pollack

Well, step 1 - do you have a storage scope?

The battery has an onboard charge controller/gas gauge. The communications protocol is I2C(ish).

Reply to
zwsdotcom

Well, step 1 - do you have a storage scope?

The battery has an onboard charge controller/gas gauge. The communications protocol is I2C(ish).

No scope. I see 9V on one of the battery terminals when the charger is connected (battery does not charge and computer doesn't work on AC). I Dont know if there should be voltage on any of the other 5 contacts.

I was able to get my hands on a working mag-safe DC in board over the weekend and swapped it into my system. It didnt help. So I know the problem is definitely on the main board (I also know that the charger is working on another system).

Any other thoughts on what components I could look at?

Reply to
Jack B. Pollack

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.