yeah i'm wrong, this is a battery switchover circuit much like the MAX703. it provides voltage to the Cuda chip from the battery, and automatically switches to the 5V rail when power comes up.
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yeah i'm wrong, this is a battery switchover circuit much like the MAX703. it provides voltage to the Cuda chip from the battery, and automatically switches to the 5V rail when power comes up. 16 comments
i removed the 'ls125. there was definitely a puddle of electrolyte underneath (it crackled and fizzed during desoldering). note that the potentiometer connection (red arrow) is right next to a pin tied to ground (blue arrow). electrolyte is conductive, so maybe it was creating a leakage current.
[DATA EXPUNGED]
@tubetime Did you figure out what the ‘LS125 is doing there? I looked it up and guess it’s just a buffer. https://www.ti.com/lit/ds/symlink/sn54ls125a.pdf @tubetime Ahhh, so IBM _wasn't_ the only company that used an RC circuit as an integrating ADC :'D! |
I've 3D printed a drive bracket for the Performa. it's designed to hold the SCSI2SD.