Hi everybody.
Can someone enlighten me as to how a 67's AC adapter interfaces with the calculator? Looking down into the plug of the AC adapter (calculator end) with the cord pointing away from me I get 5.2 VDC from the left to center pin, and 16.3 VDC from the right to center pin. The outside pins measure 11VDC right to left. I get no AC readings anywhere. Does the smaller voltage run the machine and one of the bigger voltages charge the battery?
Thanks in advance, Hal
HP67 AC adapter logic
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03-10-2006, 06:33 PM
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03-11-2006, 01:11 PM
The "bigger" voltage comes from a current source to charge the battery. You may want to measure its current to ground (not the voltage). Expect something around 50 mA, but in any case, less than 100 mA. "Ground" is the middle pin.
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03-11-2006, 05:18 PM
Thanks Bernhard for the info. ▼
03-11-2006, 07:26 PM
Here are two more for your reading pleasure: Why 65/67 card readers can be damaged without a battery
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