The HP Digital Marker continues to cause headaches. The same issue has returned. The newly installed 723 regulator can't hold the 5V DC required voltage again, dropping to 4.5V even with the trimmer maxed out. Works when it's cooled with freeze spray going up to 5.3V but begins to drop once it warms up. I think something is affecting this can IC other than them just being bad out of the box. The new one worked for about a month and then began having the exact same symptoms.
Does anyone have any suggestions as to where to look next? I tried to measure the electrolytic caps but only one would give me a value. There's something printed on them besides uF and maximum voltage. It says "1500 +-10%? Anybody know what that refers to? Should I be looking at the Circuitrim 500 ohm trimmer?
04-26-2025, 04:04 PM
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