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Harald · (This post was last modified: 11-27-2016 04:19 PM by Harald.)

I just received this HP21. It had pretty bad corrosion from a leaking battery. But it was fixable. All the ICs survived and the green/blue stuff stopped just before getting to the display.
Somebody tried to pry out the battery and did not succeed. Luckily without doing too much damage. It was easy to open after removing the two screws under the rubber feet.

But now we get to the reason for this thread:
Which Woodstocks had the serial number in the battery compartment? It is my first one that has this.

[Image: front33qa9.jpg]

Michael Eckstein · 11-27-2016, 07:02 PM

Very early HP 21 had serial number on a label inside the battery compartment. My HP 21 has a label "LOBBY P.U." on its paper box, it was one of the very first HP 21 for personal use of HP employees and it has a similar low serial number label 1503A

[Image: hp21.jpg]

PANAMATIK · 11-27-2016, 07:39 PM

(11-27-2016 02:02 PM)Harald Wrote: Which Woodstocks had the serial number in the battery compartment?

I can stretch the range of these early models with my HP-21 serial number 1505S18699. You didn't mention, that the case doesn't have engraved a serial number at its usual place. Thus you can distinguish these models from outside.

Bernhard

Harald · 11-27-2016, 10:59 PM

Were the woodstocks produced in Singapore as well as in the USA right from the beginning?

Mine in dead does not have a serial number on the case. But that was not visible on the pictures in the auction. So it was a nice surprise when I got it. Even nicer surprise was that after cleaning it was fully working.

PANAMATIK · 11-28-2016, 10:59 AM

(11-27-2016 10:59 PM)Harald Wrote: ... Even nicer surprise was that after cleaning it was fully working.

Even if not, there would have been possibility of repair. See Christmas ACT!

I now offer the repair of any woodstock calculator including repair of the internal power supply. The components can be replaced by todays transistors and capacitors. The only non replaceable chips up to now are the display drivers. Only two of my woodstock units suffered from this failure, normally they run and run and run...

Bernhard