Mac Classic - will it ever run again!!

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exxos
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Re: Mac Classic - will it ever run again!!

Post by exxos » Wed Aug 05, 2020 11:58 pm

rubber_jonnie wrote:
Wed Aug 05, 2020 11:43 pm
I've checked the datasheets and everything seems the same:
You have things so easy :lol:
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Re: Mac Classic - will it ever run again!!

Post by rubber_jonnie » Thu Aug 06, 2020 12:07 am

exxos wrote:
Wed Aug 05, 2020 11:58 pm
rubber_jonnie wrote:
Wed Aug 05, 2020 11:43 pm
I've checked the datasheets and everything seems the same:
You have things so easy :lol:
Nice to have something go my way on this one!!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Mac Classic - will it ever run again!!

Post by rubber_jonnie » Thu Aug 06, 2020 2:32 pm

Tried reading the original ROM, but it is a no go, so I think it is dead, as the 27C400s I have, being the same pinout, read just fine.

So so far looking like a dead CPU and dead ROM since all the voltages measure correct at the power plug in the mobo.

On a positive note, a guy over at the 68kMLA forum has offered to send me some boards for spares that were killed by the affectionately named 'Maxell Bomb'.

It's called this when the PRAM battery literally explodes over the mobo and corrodes things beyond the point of no return.

Given my board seems to be ok from a corrosion PoV, it will at least give me other chips to work with if I need them once the CPU is replaced. Just waiting for a CPU socket now as well, we'll see what occurs after that.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Mac Classic - will it ever run again!!

Post by Tomswork » Thu Aug 06, 2020 3:21 pm

@rubber_jonnie

That's good to hear about some spare parts and I have seen those battery pop got to love lithium batterys of any type. Those are in the mega ste as well

Tom

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Re: Mac Classic - will it ever run again!!

Post by rubber_jonnie » Thu Aug 06, 2020 3:44 pm

Tomswork wrote:
Thu Aug 06, 2020 3:21 pm
@rubber_jonnie

That's good to hear about some spare parts and I have seen those battery pop got to love lithium batterys of any type. Those are in the mega ste as well

Tom
Yeah, the parts are good news indeed.

I have removed the battery from my Mega STE, as I have a CosmosEx it sets the time at boot, so there's no requirement for a clock battery :)
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Mac Classic - will it ever run again!!

Post by rubber_jonnie » Sat Aug 29, 2020 4:03 pm

As promised, I've posted a list of the analog board capacitors I swapped in my other thread, but for consistency it's here too:

The list of analog board capacitors for my particular Mac Classic as follows:

2200uF 16v
1000uF 16v
1000uF 10v
47uF 25v x2
2200uF 10v x2
470uF 50v
RIFA PME 290 MB or equivalent. I believe the value is 10nF, but check your values.

In addition I replaced 7x 47uF 16v and 1x 1uF 16v capacitors on the logic board with tantalums.

Again, check your own board first for values and quantities.

I've also managed today to get the socket installed:

socket.jpg
socket.jpg (151.8 KiB) Viewed 224 times

And I went with the suggestion from @Tomswork to remove the plastic square from the middle of the socket to get access to the centre of the socket to allow easy access after the hot air solder so I could clean up.

Obviously I will need to drop the plastic square into the bottom of the newly installed socket to ensure the chip sits in the correct spot.

As it happened there were only 3 solder bridges and all cleaned up fine with solder wick. Continuity is all fine and I have checked for shorts too, and all is fine there too.

I have a spare ROMs now, so I can test as much as I like, but need to make sure the ROM is correctly placed in the socket to avoid killing another.

Next I need to power up ROM and CPU less to make sure all seems well in terms of power at the pins.
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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Re: Mac Classic - will it ever run again!!

Post by Tomswork » Sat Aug 29, 2020 6:30 pm

Looks good i was digging thru my macintosh box down in storage and found a mac classic board it has some issues. Nice work on the socket

@rubber_jonnie

Tom

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Re: Mac Classic - will it ever run again!!

Post by Tomswork » Sat Aug 29, 2020 7:22 pm

@rubber_jonnie

Can you see why this classic board does not work
20200827_231107.jpg
20200827_231107.jpg (380.82 KiB) Viewed 199 times
Tom

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Re: Mac Classic - will it ever run again!!

Post by stephen_usher » Sat Aug 29, 2020 7:45 pm

Ooops! :-)
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.

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Re: Mac Classic - will it ever run again!!

Post by rubber_jonnie » Sat Aug 29, 2020 10:08 pm

Tomswork wrote:
Sat Aug 29, 2020 7:22 pm
@rubber_jonnie

Can you see why this classic board does not work

20200827_231107.jpg

Tom
Yup, that'll never fly right!
Collector of old Atari things:
800XL + Ultimate 1MB, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k +APE Warp) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg), 1040STF long button floppy, 2x 1040 STFMs + Gotek, 2x 4160STE with 32Mhz booster, ROM switcher, Mega ST1, Mega ST4, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

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