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Simón Sánchez Fortuny

macrumors newbie
Original poster
Jul 21, 2020
3
0
So i’m restoring a classic II and i’m having some troble finding the schematics for the analog board...
By the way I did replace some physically leaking capacitors at the PSU stage and had some voltage readings for the hard drive beeing 3.56V and 10.50V i assume they’re suposed to run at 5 and 12v is that right? Also the Flyback transformer seems to be faulty. At first it was kinda cracky and tryed to light up the CRT, now it won’t light at all (even before replacing caps) wich were from PSU and not flyback driver.
Any ideas or schematics?
 

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Simón Sánchez Fortuny

macrumors newbie
Original poster
Jul 21, 2020
3
0
So i’m restoring a classic II and i’m having some troble finding the schematics for the analog board...
By the way I did replace some physically leaking capacitors at the PSU stage and had some voltage readings for the hard drive beeing 3.56V and 10.50V i assume they’re suposed to run at 5 and 12v is that right? Also the Flyback transformer seems to be faulty. At first it was kinda cracky and tryed to light up the CRT, now it won’t light at all (even before replacing caps) wich were from PSU and not flyback driver.
Any ideas or schematics?
If i get somewhere of course I’ll post documentation so it’s a charity society and everyone’s got his Macintosh running?
 

Simón Sánchez Fortuny

macrumors newbie
Original poster
Jul 21, 2020
3
0
So i’ve been testing the power/video/audio connector...
I brought the PSU voltages up to 5 and 12V and they all read the right value, by the way i think i may have some issue with grounding... I shocked my self trying to insert a pin to ground while testing the audio output and video output. Ground isn’t supposed to be live.
Also i’ve noticed the Samsung 9236 CF071 get’s hot as the blazes of hell the 9235 get’s hot as any IC.

The audio output works fine, i’m not sure if there’s an amplifier between the logic board connection to the analog board. I think the amp is at the logicboard...

Screen won’t light up still even if i try to patch a video signal in or get the right PWM pattern in the brightness control.
 

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2birds1stone

macrumors newbie
Jul 30, 2021
1
0
Did you have luck finding schematics? I'm trying to figure out the part number for the flyback on the Mac Classic II.
 
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