HP Forum Archive 19

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HP-67: The Red Dot Low Battery LED almost always lighting Message #1 Posted by Albert Tocar Loseggs on 11 Mar 2009, 3:57 p.m. After rebuilt the lateral PCB (totally new, between the card reader and the CPU main board), my HP-67 works fine. But a small malfunction happens. Even the battery pack (3 x Ni-Cd 1.2 V) is fully charged, after few minutes, the Red Dot Low Battery LED (RDLBL, right – bottom on the display) lighting. The only way to turn-off the RDLBL is moving the ON/OFF switch 1 mm left => normal function / right timing. I cleaned the ON / OFF switch in order to avoid undesirable electrical contacts, but no success. I don’t know if a resistor / capacitor could be sick. Suggestions? Thanks.

Re: HP-67: The Red Dot Low Battery LED almost always lighting Message #2 Posted by Michael de Estrada on 11 Mar 2009, 4:31 p.m., in response to message #1 by Albert Tocar Loseggs It definitely sounds like a poor switch contact (high resistance) problem. First,clean both the switch contact as well as the gold contact points (traces) on the circuit board. Coat the contact and circuit board with silicone grease (dielectric compound). Finally, sometimes it helps to bend the contact out slightly to get more contact force on the circuit board. Buena suerte, Michael

Re: HP-67: The Red Dot Low Battery LED almost always lighting Message #3 Posted by Charles on 15 Mar 2009, 2:41 p.m., in response to message #2 by Michael de Estrada I had the same problem when I used cheap rechargeable batteries. The problem disappeared when I replaced them.

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