jmacz journey

[jmacz]

The SE itself seems to work. I removed the accelerator and that gives me a chime and the Mac will boot off a floppy. It's got 1MB of memory and seems to have the proper FDHD roms/swim, although the ROMs have a slightly different part number 341-0701 and 341-0702. Was expecting both to start with 342- but these are 341-. They are still FDHD ROMs I believe but maybe slightly older?

I guess the todo item then is to figure out what's going on with the accelerator board. Not sure if the FPU is optional or not but it's clearly missing. Looks like it's supposed to have a MC68882FN33A in there (based on other pictures of this accelerator online). The accelerator board itself doesn't have anything that looks suspect, it's pretty clean and looks perfect on first glance.

 

[jmacz]

Hmm, interesting. The floppy drive carrier was missing two of the four screws that mount it to the chassis, and one of them was not the usual screw either. So I pulled the floppy drive out and it's an 800K drive. Will have to pull a 1.4MB drive out of one of my other Macs to ensure the roms/swim are working. Previous owner must have tinkered around inside as obviously has the accelerator (minus the FPU), missing screws, wrong floppy drive...

 

[Daniël]

There's some discussion about this AE accelerator here:

https://68kmla.org/bb/index.php?threads/for-sale-applied-engineering-macintosh-se-accelerator.40775/

The black connector is likely a PDS passthrough of sorts, for additional upgrades like video cards.

 

[zefrenchtoon]

There's some discussion about this AE accelerator here:

https://68kmla.org/bb/index.php?threads/for-sale-applied-engineering-macintosh-se-accelerator.40775/

The black connector is likely a PDS passthrough of sorts, for additional upgrades like video cards.

Like the Radius MagicBus connector on Radius accelerators

Very lucky BTW. I would try the lottery if I was you

 

[jmacz]

MacPlus is finally finished. Upgraded to 4MB, floppy drives (internal and external) cleaned, rust removed from rear ports, internal bracket on the motherboard, and corrosion removed from the battery connectors. Also the battery door was missing so 3d printed one.

 

[jmacz]

@alexGS on this thread below had discovered that the PowerBook 500 series batteries will draw as much current as it can while charging thus requiring the charging brick to restrict the amount of current it supplies to the battery.

500-series alternative power supply learnings

I have a 500-series power supply that worked beautifully after a re-cap - then after a week or two, it went pop. It seemed a MOSFET had shorted - and then a spark jumped from that to the transformer leg, eroding a PCB track. But actually, the MOSFET tested fine on removal. The problem appears to...

68kmla.org

The custom made power supply I had done (pictured below) was using two 16V 4A power supplies which isn't good for the NIMH batteries I'm using (2000/2100 mAH) that need to max out at around 2A during charging.



So I replaced one of the two 16V 4A power supplies with a 16V 2A one. So it's got 16V 4A for the vmain (more than it needs) and a 16V 2A for the vbatt. Same enclosure as last time but this time I'm not painting it.

 

[jmacz]

I was able to procure a third PowerBook 500 series battery from my friend @techstep.

I cracked it open and replaced the old cells with new 2000 mAH NiMH cells. Testing it out in my 540c, it also had uncorrectable errors via Lind. This one only had 1 error though as opposed to my other battery which had 4. I swapped out the eeprom with a brand new one and that allowed Lind to reset it and no more errors. Seems like these memory chips go bad in these batteries? All 3 of the batteries I have procured have had bad memory chips now.

So I'm 2 for 3 now on fixing these batteries. The one failure was due to a bad Apple logic chip which isn't replaceable.

Happy to have 2 working batteries in my 540c now.



I could have epoxy sealed them but used tape incase I ever need to replace the cells again.

 

[mdeverhart]

I swapped out the eeprom with a brand new one and that allowed Lind to reset it and no more errors.

Did you ever post any notes on the EEPROM swap? I followed your 540c rebuild thread but don’t recall seeing it. I apologize if I missed it! I have a 520c with what I think is an intact (but dead) battery that is love to get going again.

 

[jmacz]

Did you ever post any notes on the EEPROM swap? I followed your 540c rebuild thread but don’t recall seeing it. I apologize if I missed it! I have a 520c with what I think is an intact (but dead) battery that is love to get going again.

I briefly mentioned it in one of the other threads (might have been someone else's thread on the PB 500 battery).

The battery tools were failing to update/write values to the EMM board and so I thought I'd try replacing the Atmel 93C66 chip. The one I picked up is the Microchip 93C66-E/SN. Here it is on Mouser:

https://www.mouser.com/ProductDetail/579-93C66-E-SN

Used hot air to get the old one off and then soldered the new one in its place. Afterwards, ran the Lind tool and it will say something about the memory being totally corrupt and if it's ok to rewrite the whole thing to factory defaults. After the write, it was good to go.

 

[mdeverhart]

Awesome, thanks! I’ll give that a shot if replacing the cells isn’t enough.

 

[3lectr1cPPC]

I’m probably doing this myself soon, I just got a battery spot welder. Can’t wait to have my vintage laptops on battery

 

[techstep]

What's the approximate battery runtime on one of these post refurbishment? Just curious

 

[jmacz]

What's the approximate battery runtime on one of these post refurbishment? Just curious

Just messing around, nothing very compute intensive, I am getting about 1.5 hours or so on a single battery. I let it sit idle once and it went 2-3 hours.

 

[jmacz]

I’m probably doing this myself soon, I just got a battery spot welder. Can’t wait to have my vintage laptops on battery

I just bought prebuilt packs on Amazon. No welder needed and they are not expensive.

Amazon.com

 

[bigmessowires]

I'm a little surprised you aren't seeing longer run times with the rebuilt batteries. Do you know the specs for how the original batteries performed?

 

[jmacz]

I had thought it was around 1.5-3 hrs per battery based on vague memory of hauling it around to libraries back in the day.

But looking at the everymac specs it looks like it’s stated as 2.5 - 4hrs per battery.

Maybe I need to test it some more.

BUT, note that I have all of the power savings turned off because I am still having an issue with the Finder crashing when the laptop enters sleep. This is under 7.1.2. On my to do list to debug so I disabled all the power saving features and that might be why? I also have the brightness turned up all the way so that clearly won’t help.

To be honest, I am happy even with the 1.5 hours.

 

[3lectr1cPPC]

I just bought prebuilt packs on Amazon. No welder needed and they are not expensive.

Amazon.com

That is very tempting.
I have two battery packs, but one has a rotten thermistor that I need to find a replacement for. This makes me think though - does that tenergy pack you linked already have one inside? If that's the case, I could just get one of those for that pack to avoid having to find the right replacement. Then I could try building a pack myself with the welder for my other battery, then compare runtimes?

 

[jmacz]

That is very tempting.
I have two battery packs, but one has a rotten thermistor that I need to find a replacement for. This makes me think though - does that tenergy pack you linked already have one inside? If that's the case, I could just get one of those for that pack to avoid having to find the right replacement. Then I could try building a pack myself with the welder for my other battery, then compare runtimes?

I'm using the stock thermal sensors, the prebuilt packs do not have one inside. They do have a fuse, but not the thermal sensor.

 

[3lectr1cPPC]

I might be getting my components confused - I am talking about the black tube thing that was sandwhiched between the cells in the original pack. Is that a fuse or a thermal sensor? Are you saying the thermal sensors are the blue things on the ribbon?
I don't know my components very well...

I'd post a photo of what I'm talking about but it appears I've managed to misplace the parts from my batteries that I gutted months ago. Of course I know exactly where the bag with the leaky cells is...

 

[3lectr1cPPC]

Found them. The black klixon part is the one that was rotten out on one of the batteries. I also only appear to have one of the other part next to it in the photo, so I may need one of those too? Not too knowledgeable about these battery parts!