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Re: HP-25 fails to store programming steps - Printable Version

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Re: HP-25 fails to store programming steps - Mike Morrow - 01-28-2009

Your point is well taken, Randy.

I did not mean to endorse the extremely poor, incompetent, negligent HP design of the Woodstock battery charging system. I do like the mechanical aspects of the Woodstock battery pack, with its integrated compartment door.

The cheapest Woodstock, the HP-21, cost the equivalent of $494 2008 dollars. I can't imagine why HP thought it would be acceptable to market an expensive product that could be destroyed easily and innocently while connected to the charger if the battery pack was missing, poorly connected, or so degraded as to not provide the charging voltage clamp needed to prevent the spikes that kill the machine.

Whenever I hear fanatical declarations of HP design excellence, I think in response immediately of this Woodstock charging system, the HP magnetic card reader roller, the early Spice series press-fit circuit construction, and the flimsy case, poor battery compartment design, the needlessly complex charger connector plug of all the Spice series, the HP-28 battery door, etc.

I will admit that my 33-year old HP-21 and HP-25 Woodstocks are still going stong today, but likely more from luck than prudent usage. I didn't even know about the charger problems until a few years ago.


Re: HP-25 fails to store programming steps - Michael de Estrada - 01-28-2009

Actually, my original HP-21 failed not because of battery/charger issues, but because several keys began to malfunction, and I could not remove the keyboard for cleaning because it was heat-staked to the front half of the case. I could have broken the plastic staking posts, but there would be no way to re-secure the keyboard. Compare this to the HP-35 and other classics where everything was screwed together, and it could be completely disassembled for repair and then re-assembled. Still, I truly loved the very small size of my HP-21; it was the only truly pocket size LED calculator HP ever made.

On a side note related to the topic of the original post, I personally believe the Voyager series were the highest quality calculators ever made by HP, and the keyboard on my heavily used HP-15c still works perfectly to this day.