Paperboy AR3 10.3v unreg feeding power on reset

joeyoravec

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Howdy. Taking a look at my buddy's paperboy. On schematic sheet 6B the AR3 feeds 10.3v unreg into an opamp. This generates a power-on reset signal; this should be released as soon as the power supply comes up.

I'm attaching a screenshot of his 10.3v on the oscilloscope. Every time this signal dips it asserts the power-on reset signal again. That's the squarewave you're seeing in the next screenshot.

It's 10.3v unregulated so I'm expecting some nastiness, but not that much. I can't decide from that trace if there's some sort of rectifier issue, or if the filter capacitors are just weak. Next time we meet I'll pull the AR3, pull the caps, and check the rectifier.

Can anybody comment, or even better capture an oscilloscope trace of their 10.3v line?
 

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