The following article, although intended to be a parody, is so close to reality that it hurts. You see, 65 Notes and PPC Journal ran many articles describing bizarre modifications of HP calculator hardware (usually with overly-detailed instructions) and even more bizarre ways of burning up the thermal printheads on the printing models (such as the HP-97) by printing non-normalized numbers. One member decided to illustrate the absurdity of it all by being even more absurd. (The huge intentional ink blob in the article cannot be reproduced in plain text; use your imagination.)
Key concept: The HP-25 had no printer. At all. Ever.
Enjoy this glimpse into The Way Things Were... 20 years ago!
Justus A. Villa (2785)
"PPC Journal," September/October 1978
Volume 5, Number 8, Page 5
In response to "Can You Print This?" (V5N6P24), I enclose a print-out produced on my HP-25. Hopefully you may see fit to permit me to share the following methodology with the rest of the membership:
VERY carefully (the machine should preferably be out of warranty) turn the ON/OFF switch to the OFF position.
Place the calculator, face down, label towards you, on a old newspaper on a sturdy table in a well-lighted, well-ventilated work area.
VERY carefully remove the battery pack. A good procedure to follow is the one in V[huge ink blob]P4. If a No. 3AA tool is not available, use a No. 3AB or a toy claw hammer.
(For best results, this step should be done in the dark or under a safelight): Cut, do not tear, a 7.5 cm (2.95 in) length of HP 9270-0513 thermal tape, using any tool appropriate for the purpose. (Try not to cut yourself.)
With the lights back on, wrap the tape fairly tightly in a clockwise direction around an A.W. Farber No. 850 "Black Magic" pencil. This is if you happen to be in the northern hemisphere. In the southern hemisphere you would naturally go counterclockwise. Recall the old Welsh mnemonic Cnwk Cyd Wlk Nsl Cnd Wkyl Snl! If in doubt, go clockwise for 3.75 cm (1.48 in) and counterclockwise the rest of the way. Incidentally, this is a neat test for checking out your hemisphere. In wrapping take particular care to go counter to the natural curl of the tape.
After securing against unrolling with 3M No. 230 Drafting Tape, VERY carefully remove the roll from the A.W. Farber No. 850 "Black Magic" pencil, using lineman's tweezers, and introduce same to the battery well, taking particular care not to disturb in any way the contacts of the battery.
With the left hand raise the thicker end of the calculator sufficiently to permit positioning the PRGM/RUN switch halfway between PRGM and RUN with the right middle finger. Bear in mind at all times that this is a scientific project.
Without lowering the calculator pass two No. 12 or No. 14 (any make) rubber bands around it, one between the first and second rows of keys, and the other between the fourth and fifth rows, taking particular care that the rubber bands are not in any way twisted or distorted.
(We are almost to the end.) Still without lowering the calculator, put it in its case, label end first, and secure the zipper, taking particular care to move smoothly and deliberately.
Leave undisturbed for 5½-6 hours, no longer. At end of same retrace the foregoing steps in reverse order. In unwrapping the tape recall the old Welsh mnemonic Nsl Wwk Cwk Snl Wkn Ckn Cwk! Take particular care not to wind up in some hemisphere where your money's no good and you don't know the language. (In some contries it is a serious offense to have in one's possession clockwise or counterclockwise thermal tape, as the case may be, so check your local laws!)
This procedure has been found to work just about every time with three different machines. The only truly critical part is the length of the print period. If you go slightly over 6 hours, you will enhance the contrast, true, but go slightly over that and, suddenly, you get a blur. This phenomenon is not completely understood as yet, so don't take foolish chances.
Justus A. Villa (2785)