"Macintosh"

bunnspecial

macrumors 604
Original poster
May 3, 2014
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I had the opportunity to buy this recently.

It just arrived today, so I haven't taken it apart to document the LoBo(something which I will do in due course). The floppy drive also won't accept a disk, but fortunately I was able to boot it via an external.

This was bought from its original owner, and I'll see what I can get out of him about its history. I don't THINK it's had a RAM upgrade.

The SN decodes to the 17th week of 1984, which if I'm counting correctly means April 22-27.

IMG_5328.jpg
IMG_5329.jpg
IMG_5331.jpg
 

MacTech68

macrumors 68020
Mar 16, 2008
2,249
167
Australia, Perth
Wow - impressive that somebody never upgraded it.

Interesting with the week numbers - I suspect this machine MAY have been pulled off the production line due to a fault, and subsequently refurbished with a factory repaired motherboard 2 weeks later.

Note the OKI RAM ICs seem to have been manufactured Week 18 of 1984. Then there is ONE replacement Motorola dated Week 19. Since the RAM ICs are likely to have been the most rare part back in 1984, it's likely those dates are true.

Could it have been an Apple Service repair instead? Yes, that's likely too, but given the closeness of the manufactured dates of the OKI and Motorola RAM, I'm leaning towards a factory refurbishment - ie, this might be how it left the production line after failing initial testing.

The other parts that seem to be very late to a Mac128 motherboard (ie - in short supply) are the D-sub connectors (these usually have a 4 digit date stamp too).

Other ICs in your picture show a Week 08 of 1984 manufactured date - these would have been in plentiful supply at the time.

EDIT:-
- also note that the board already has the revision of the resistor pack attached to the 6522.

I'd love to see the Analog board. ;)
 

bunnspecial

macrumors 604
Original poster
May 3, 2014
7,202
4,300
Kentucky
Thanks for your input and information on it. My "gut" after looking was that this one was all straight, and I appreciate your confirmation and observations.

I will pull it apart again and document anything requested-I know that finding one that was never upgraded can be an adventure in and of itself, so I want to put all I can out on this computer. I'll do a quickie snap of the analog board for you, but I lose the picture occasionally on it(it will come back with a smack on the side) so I need to redo the flyback solder joints. I'll fully photograph the analog board when I do that.
 

MacTech68

macrumors 68020
Mar 16, 2008
2,249
167
Australia, Perth
If when you lose the picture, the screen is completely blank, then this is most likely a bad solder joint on the video pin of the 10pin power/video connector.

The pic below is with the screen facing downward.

128K Analog Comon Cracked Solder Video Pin.jpg
 

bunnspecial

macrumors 604
Original poster
May 3, 2014
7,202
4,300
Kentucky
Thanks again-it looks like you were correct that it was reworked and sold a few weeks after initial production.

All of the joints consistent and very clean, so I suspect that everything on the board was done at the factory. I know that finding one that hasn't been upgraded or repaired is somewhat uncommon, so I want to document this as best as I can.

_DSC2568-2.jpg

[doublepost=1527345405][/doublepost]Also, here's the analog board

_DSC2569-2.jpg
 
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MacTech68

macrumors 68020
Mar 16, 2008
2,249
167
Australia, Perth
Certainly appears to be a factory replacement.

The Class X2 Capacitor on your analog board seems to have already popped.

The Analog Board also looks like a later replacement. I see a flat-pack rectifier bolted to it's heatsink on the power supply output and a litzwire horizontal width coil.

Battery has leaked and there is rust on the chassis frame. :(

Just making observations - no doubt you have seem some of these.
 
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MacTech68

macrumors 68020
Mar 16, 2008
2,249
167
Australia, Perth
Nice pics.

I'd guess this board was from an original 1984 Week 38/39 - it looks to have had it's last major repair around Dec 1987.

Apple mods & component 'upgrades' are visible, but it's certainly NOT the most upgraded board. This is fairly early in Apple Service's learning curve.

If required I can point out all the modifications I see.

I fear that the battery leak has done this board a disservice. Unprotected metals are having a hard time on this board (corrosion). I fear that there will be a number of completely black solder pads and tracks on the other side. :( Sadly, this is common from battery leaks - a feature I never used to see these boards in. It's like seeing an old friend looking worn out and ill. :eek:
 
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