--- In ultralightdx@..., David Henry wrote:

> Apologies for the bandwidth. I will take this off-list with one of the
> guys if it is not appropriate to keep posting about it here.

Speaking only for myself, I think it's appropriate. Someone else may have the same problem someday, and we ought to try to solve it. Scott Willingham may have a suggestion. You may be able to reset it by leaving the batteries out for a long time, but how long I can't say. When the clock quits, I guess that means the internal supercap is flat, which should let the processor reset.

I can't see how charging the batteries outside the radio could cause this problem. There's no way NiMH batteries will exceed the voltage of new alkalines, no matter what you do to them. They might hit 1.25 V, but if you really sock it to them by overcharging, they will self-destruct.

If you're measuring the voltage external to the battery box (so the contacts are in the circuit, as opposed to measuring right at the cell terminals inside the battery box), it doesn't sound like the radio is drawing excessive current. (My thought was that one of the contacts in the battery box was the problem.)  Did you happen to measure the voltage after the battery indicator went hollow?

If you leave the same cells in the radio, turn it off for, say, 15-30 minutes, then turn it on again, what happens?

On the off chance that there's a flaky solder connection on the board, here's how I examine boards I've built. I take a digital photograph at the highest resolution, and look at it full-size on my PC. At that magnification you might notice a bad joint.

I wish we could get a schematic of this radio.

73,

Jim, KR1S
http://qrp.kearman.com/