PowerBook 500 Series Battery Rebuild Failure (Oops, all dead EMMs!)

[croissantking]

Have now tried a third EMM board - oh dear.

 

[jmacz]

Hmm, so ruling out some obvious ones:

• All four ribbon wires are connected? The EMM board takes two grounds, one vcc, and the two inner ones used to talk to the laptop.
• The continuity is there from the external pads (on the case) to the emm board?
• You are seeing power get to the EMM chip with the battery connected? I think Vcc was pin 14 and ground was pin 28 (on my phone right now so can’t check but I had it in one of my threads).
• The internal spring loaded connectors in the battery bay are making contact with the battery external pads? You can also check continuity all the way through.
• The battery pack has some charge?

 

[jmacz]

Also no corrosion on the internal spring loaded contacts?

Oh and was the one SMD cap on the main board near the spring loaded contacts replaced? I think someone mentioned it might be involved with the battery functions.

 

[croissantking]

Getting a bit further now…

 

[croissantking]

All four ribbon wires are connected?

Yes

The continuity is there from the external pads (on the case) to the emm board?

Yes

You are seeing power get to the EMM chip with the battery connected? I think Vcc was pin 14 and ground was pin 28 (on my phone right now so can’t check but I had it in one of my threads).

Yes, although my multimeter reads -5V on pin 14.

The internal spring loaded connectors in the battery bay are making contact with the battery external pads? You can also check continuity all the way through.

Yep, I think so. I cleaned up the battery contacts with IPA and then used some deoxit on those plus the internal spring loaded connectors.

• The battery pack has some charge?

Yep.

 

[croissantking]

Also no corrosion on the internal spring loaded contacts?

Oh and was the one SMD cap on the main board near the spring loaded contacts replaced? I think someone mentioned it might be involved with the battery functions.

Recapped, yep.

 

[3lectr1cPPC]

Have you checked for voltage on the EMM communication pin on the battery?

 

[3lectr1cPPC]

You should get around 5 volts between battery negative and the pin shown in the photo. Mine’s a little low because I still haven’t rigged up a power supply with working VBATT so I can’t actually charge my otherwise working battery…

 

[croissantking]

View attachment 73317
You should get around 5 volts between battery negative and the pin shown in the photo. Mine’s a little low because I still haven’t rigged up a power supply with working VBATT so I can’t actually charge my otherwise working battery…

I don’t get 5V - it’s reading 0.03V. What could be wrong?

 

[3lectr1cPPC]

Trace the path from that contact to the EMM board on the ribbon and see if it’s connected. If it is, the EMM isn’t generating its operating voltage for whatever reason.

 

[croissantking]

Well, I got one of my EMM boards to work, it puts out 5V on the communication pin. Lind and Emmpathy tell me it has an uncorrectable error, so I don’t really know if it’s salvageable. However, it’s taking a charge as we speak.

 

[jmacz]

Well, I got one of my EMM boards to work, it puts out 5V on the communication pin. Lind and Emmpathy tell me it has an uncorrectable error, so I don’t really know if it’s salvageable. However, it’s taking a charge as we speak.

Nice, progress! How did you get it to detect? What was wrong?

For the uncorrectable errors, some folks said you need to keep trying a few times. For me, after 10 attempts, I gave up. It looked like the errors were in the stored data in the battery so I decided to replace the Atmel 93C66 memory chip. After doing so, Lind reported the memory was totally corrupt (instead of the usual 1-4 errors) and asked if I wanted to overwrite it. Once overwritten, it's been working great. No more errors.

This was the one I used: https://www.mouser.com/ProductDetail/579-93C66-E-SN

 

[croissantking]

I went back to inspect the first EMM board I tried out, and found a broken transistor. I swapped it out with one from another board, and that got it working.

I've ordered the memory chip you linked to. The batt does seem to be working fine even with the errors, giving around 1:20 runtime.

 

[3lectr1cPPC]

Was the transistor physically damaged or did you test it somehow?

 

[croissantking]

Was the transistor physically damaged or did you test it somehow?

Physically broken, probably happened while dismantling?

 

[jmacz]

Just curious, which transistor went bad for you?

I had an issue with the one pointed at by the blue arrow on one of my batteries and had to replace it. (Ignore the other arrows, I am re-using a previous picture).



Mine wasn't physically broken like yours (or maybe it was, I just wasn't visually able to see damage).

 

[croissantking]

Just curious, which transistor went bad for you?

Mine wasn't physically broken like yours (or maybe it was, I just wasn't visually able to see damage).

It was the transistor immediately to the right of the one labelled with the blue arrow in your photo.

Check out the EMM chip on my third-party battery, it's labelled 68HC705. Is this compatible with the Apple ones? @GRudolf94 previously commented that the Apple EMM might be a 68HC05E1.



I've got 8 spare cells to assemble another battery, though none of my EMM boards are showing signs of life yet.

 

[3lectr1cPPC]

You have a third battery 500 series battery?? I didn’t know that such a thing existed!

 

[croissantking]

You have a third battery 500 series battery?? I didn’t know that such a thing existed!

Yes!

 

[3lectr1cPPC]

Fascinating. Is that one rebuilt and working, and do you have a picture of the whole EMM? Same cell configuration?