Byrd
Well-known member
Hi all,
I've been restoring a Mac Classic II for some time, it came to me in fair shape with the logic board being the best looking part of the lot - turned on to a "flup, flup, flup" sound and nothing else.
So far I've:
- Recapped motherboard (a pleasant job - it wasn't that degraded)
- Recapped analog board (the caps on the analog board were badly leaking - probably the worst I've seen but cleaned up well with no apparent trace damage), reflowed what I could
... the above resulted in the same "flup flup flup" sound as before, +5 and +12V voltages very low
Next steps, thanks to reading these forums ...
- Replaced zener diodes DP5 and DP7 with same (the old diodes checked out OK)
- Replaced CNY75GB optocoupler with same (TDA4605 is on the way)
... this resulted in a loud clear chime, solid +5V ~ 5.00V and +12V ~ 11.8V voltages
... I can boot from floppy or a floppy Emu assume to desktop
However, no CRT activity whatsoever (I've tried to adjust brightness on the back pot, reflowed analog and neck board). The back of the neck is glowing orange and I'm a tad stumped. Short of waiting for that TDA4605, would others have any further pointers?
Thank you
JB
I've been restoring a Mac Classic II for some time, it came to me in fair shape with the logic board being the best looking part of the lot - turned on to a "flup, flup, flup" sound and nothing else.
So far I've:
- Recapped motherboard (a pleasant job - it wasn't that degraded)
- Recapped analog board (the caps on the analog board were badly leaking - probably the worst I've seen but cleaned up well with no apparent trace damage), reflowed what I could
... the above resulted in the same "flup flup flup" sound as before, +5 and +12V voltages very low
Next steps, thanks to reading these forums ...
- Replaced zener diodes DP5 and DP7 with same (the old diodes checked out OK)
- Replaced CNY75GB optocoupler with same (TDA4605 is on the way)
... this resulted in a loud clear chime, solid +5V ~ 5.00V and +12V ~ 11.8V voltages
... I can boot from floppy or a floppy Emu assume to desktop
However, no CRT activity whatsoever (I've tried to adjust brightness on the back pot, reflowed analog and neck board). The back of the neck is glowing orange and I'm a tad stumped. Short of waiting for that TDA4605, would others have any further pointers?
Thank you
JB
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