My brand-new HP29C (S/N 1711Axxxxx; got it on ebay a few weeks ago) gave me a scare: keys pressed in run mode would have unexpected results. For example, the 7 key pressed several times would put different numbers on the screen.

I removed the battery, and let it recharge for half a day. I put it back and the machine is working fine. I can therefore assume that the problem was low battery, even though the low-battery indicator (it's all the decimal points but the real one lit, right?) was NOT on.

For what it's worth, the battery pack has been rebuilt using Radio Shack 1000mAH NiCd cells (it arrived this way).

Comments?

/ji

I have found that getting wrong digits on Woodstocks is almost always caused by battery leakage residue (sometimes invisible) on the keyboard etches or contact posts. Open the machine and clean well. Unfortunately most 29C keyboards do not have the through holes under each key that give you some access to the etches on the top side of the keyboard. In bad cases it's ultrasonic cleaner and low oven time...