croissantking's conquests

[zigzagjoe]

Not impossible but definitely fiddly. I did this to a 68882 with a lead borrowed from a vintage metal cap. I suspect there are better sources for pins, though. Maybe SMD PGA pins exist?

 

[croissantking]

I've just completed a battery rebuild for my iBook 300 - it's taken a full charge and seems to work great.

 

[jmacz]

Were they pre built or did you solder/weld the tabs yourself? Nice!

 

[croissantking]

Were they pre built or did you solder/weld the tabs yourself? Nice!

The cells were purchased loose and untabbed, and I assembled it using a spot welder.

 

[CC_333]

I wish you were ~5,000 miles closer, because I have maybe a half dozen or so of these that could be rebuilt.

c

 

[croissantking]

I wish you were ~5,000 miles closer, because I have maybe a half dozen or so of these that could be rebuilt.

It’s well worth the effort, I’m getting 3-4 hours’ usage out of my rebuilt one. Running untethered increases the enjoyment of these old laptops significantly.

 

[crazyben]

It's more than it opens the door for a load of projects. The 840av was planned for release with a bootable 7.1.2 in ROM, you could add this back in some day. You could also potentially do in computer ROM development with one of the new Quadra compatible ROMs.

Checking the date code, it is an Aug 1992, so not a release day machine, but interesting.

They're quite hard work - even recapping is fiddly. Take more care than usual. There is a lot of plastic near caps and hard to reach capacitors.

If you find a source of replacement DSPs, let me know before you order, I could probably do with one too. My dad's is battery bombed and it attacked the DSP a little.

I have one that is recapped and works great. How rare are these?

 

[croissantking]

I received another 540c today, purchased on eBay in its original box (unfortunately not in great condition). It came with some correspondence too, which I thought I’d share as it’s interesting.

The machine boots up and has a good LCD - but only has 12MB RAM, and no other upgrades. I feel like second hand machines in the UK usually don’t come with the kind of nice surprises that they might if they were purchased in the USA or Japan. Maybe the Brits are more frugal…

 

[Snial]

I received another 540c today, purchased on eBay in its original box (unfortunately not in great condition). It came with some correspondence too, which I thought I’d share as it’s interesting.

The machine boots up and has a good LCD - but only has 12MB RAM, and no other upgrades. I feel like second hand machines in the UK usually don’t come with the kind of nice surprises that they might if they were purchased in the USA or Japan. Maybe the Brits are more frugal…

In the late 90s Brits had a lower income; $1=£1 and keen memories of doing everything on a 1K ZX81 ;-) !

 

[croissantking]

Yup. But reading the paperwork, it seems the original owner wasn’t very happy with the reliability of this machine, so perhaps replaced it sooner rather than later.

 

[croissantking]

My newly acquired 540c (right) has a much brighter, whiter screen, which on its own has made this a worthy purchase. I get the impression it’s had low usage.

 

[finkmac]

isn't the yellow tone just an old worn CCFL backlight? Presumably you could replace that with an LED backlight...

 

[3lectr1cPPC]

It can be caused by the CCFL backlight, but sometimes it's the LCD itself. One or more of the layers, I believe it's the backlight diffuser layer can go yellow, so sometimes replacing the backlight won't make an LCD much less yellow.

 

[croissantking]

It can be caused by the CCFL backlight, but sometimes it's the LCD itself. One or more of the layers, I believe it's the backlight diffuser layer can go yellow, so sometimes replacing the backlight won't make an LCD much less yellow.

That’s good to know. I do want to fit an LCD backlight to my PB180, which is very dim.

 

[olePigeon]

It can be caused by the CCFL backlight, but sometimes it's the LCD itself. One or more of the layers, I believe it's the backlight diffuser layer can go yellow, so sometimes replacing the backlight won't make an LCD much less yellow.

If you get an RGB LED backlight somehow, you could adjust the blue level of the LED to offset the yellow.

 

[croissantking]

I picked up an 840AV today, a non-runner (thanks to @Adriana). They also threw a second motherboard in with the deal, and some accessories.

View attachment 70474View attachment 70477

Both motherboards have had significant cap leakage, but the spare motherboard is in better shape:

View attachment 70478

The cap damage isn’t too terrible:

View attachment 70486

It cleans up like this with IPA:

View attachment 70487

It’s an earlier board with a ROM SIMM:

View attachment 70479

The board inside the case is a later one with a green PCB, and loaded with RAM and VRAM:

View attachment 70480

It’s had a battery leak:

View attachment 70481

The caps have done a tremendous and shocking amount of damage, I’m not sure I can save this one. Many of the fine pinned ASICs look like this:

View attachment 70483View attachment 70482

There’s also two SCSI hard drives and a 24x SCSI CD-ROM drive (must be a pull from a very late 604e machine?), condition unknown.

View attachment 70484View attachment 70485

I have a feeling its going to be a long road ahead, but I’m excited to get started. My plan is to try to get the brown motherboard working first as it’s definitely the one in better shape. I need to test the PSU as well.

I finally got around to testing my two 840AV boards, now cleaned up and recapped. I am using an adapter with an ATX supply, as the Quadra’s PSU is dead.



I press the power button, and the PSU comes to life (interestingly, an ADB keyboard’s power key doesn’t do anything). Neither board chimes, the only sign of life is a green LED.

 

[3lectr1cPPC]

That's a typical 840AV failure mode, you've probably got more bad traces somewhere.

 

[croissantking]

That's a typical 840AV failure mode, you've probably got more bad traces somewhere.

Time to get that microscope!

 

[pizzigri]

Not impossible but definitely fiddly. I did this to a 68882 with a lead borrowed from a vintage metal cap. I suspect there are better sources for pins, though. Maybe SMD PGA pins exist?View attachment 72216

I use a dead 486 cpu. Cut away the leg at the root, round part with a cheap but very sharp wood chisel and carefully solder it on the broken pin location after filing it down to have a flat surface. A 486 has perfectly identical pins all the way to the 68040. Repaired a few over the years.

 

[mg.man]

I use a dead 486 cpu...

@croissantking - I may have a donor CPU you could use for this. Drop me a PM if you're considering a repair.