Note from Guy -- Legal-lawyer talk time:
I remember the first time I saw a handheld L.E.D. calculator, it was around the Fall of 1973 when I was 12 years old and we (my parents and I) were over at a friends house for dinner. After the meal had ended my father and his friend went out to his workshop to look at a project that he was working on, so me being my fathers shadow tagged along. The project was a beautiful redwood water wheel/millhouse replica and the gentleman was having some difficulty calculating the proper spacing for the chambers that catch the water.
He had purchased especially for this project a Texas Instruments SR 10. At 150.00 it was a fairly extravagant purchase at the time but it helped him make the necessary calculations to finish his job. Needless to say when he let me fool around with it I was HOOKED!! The sleek case, glowing display and clicky keys held me in a sense of wonder for the remainder of the evening.
The feeling I had of being able to press a key and have the number appear on the display and then manipulate that number with other numbers is still, to this day, indescribable. I swore to myself that night that I was going to save every penny I could to own one and impress my Junior High friends and ACE every math test old Mr. Hoover could throw at me!!!
Well, it took me almost a year but I had scraped together enough money to finally purchase an SR 10, but by that time the price had dropped and other more elaborate and expensive models had begun to appear. I was torn, High School was around the corner and I thought I would need more power! (Ooh Ooh Ooh Ooh!!!) So instead of spending all the money I had saved I purchased a Unitrex Mini-Handy 80R which I summarily destroyed about one month later! (A stupid accident involving a shirt pocket, running and a sidewalk!)
Anyway, I was unable to get my next calculator fix, as it were, until the middle of my freshman year. Prior to this I had been exposed to the injustice of watching many upperclassmen walk up and down the hallways of my school with padded vinyl or even (shiver..... Hewlett-Packard) genuine leather cases strapped to their belts. Oh yes, I KNEW what each of them contained by name and model number, I KNEW the keyboard layout of each one, I KNEW I had to have one just to be part of the NERD crowd, I KNEW I would have to throw about1.0000000 10 newspapers to afford one!!!
Just to get a case of some type strapped to MY belt I knuckled under and bought a Corvus 411. I avoided showing off this calculator as it only had the basic slide-rule functions. What can I say? I was impatient and undisciplined!!
While I tolerated owning this (in my then humble teenage opinion) substandard calculator, I began a letter writing campaign to Texas Instruments and Hewlett-Packard requesting product information and pricing, thinking I would get a better deal by going straight to the source. Hardee har har!!! Little did my capitalistically naive mind understand the true meaning of free enterprise. Manufacturers Suggested Retail Price became a four-letter word to me!! But I did receive a lot of nice pictures of high-end calculators!! I wish I had all of the literature and advertising that I had amassed then today.
Things went on like this for months, I had my eye on a TI SR 51A but the cost was still too high so I bought gimmick calculators in the meantime because I was unable to manage my money and stay focused! A Radio Shack version of the Casio CQ- 1 comes to my mind, I took this one apart after a couple of months just too see what was inside.......it broke. I then traded something, I don't remember what, for a 3 year old Commodore, (model unknown) I took this one apart also.........it broke. I quickly learned what THE WHOLE IS GREATER THAN THE SUM OF ITS PARTS meant!! I even overloaded the chips and L.E.D.s just to see what would happen!! I was SICK!! ( Although looking back, I gained a lot of knowledge that I use today in my restoration work.)
By my Junior year I had grown up somewhat and was earning more money, the SR 51A was mine!!! I loved this calculator!! I used it in all my classes, even Government! I sold this unit during my Senior year and purchased a TI 58. This was one slick machine, I recall programming it to spell out messages if you held the calculator upside-down!
All during this period of my life I still yearned for a Hewlett-Packard, they were to me then(and still are) the ultimate in technology and durability. Their quality and appearance were awe inspiring. I never went into a department store without stopping by the calculator counter to play with these machines. Only the more upscale stores carried the HP line and often they were displayed in velvet lined glass cases which seemed to add to their mystique.
It has taken me 20 plus years, but I am finally a Hewlett-Packard owner, I have 12 models in my growing collection of calculators and have the goal of attaining all HP handhelds from Classic to Present day. A pretty lofty goal, yet one that is attainable given enough time!
Having become a semi-rational adult I gave up the calculator crazies and got on with my life, but always in the back of my mind, the desire to own an obscene number of these marvels has haunted me! When I found out that there was an organization devoted to collecting calculators, the fuse was lit, and so I began my quest!
Having no experience collecting much of anything except dust, I was uncertain about how much I should invest and what condition I should look for when buying an old calculator. I learned quickly that spending more than $5.00 was almost unheard of and that condition is important, but not so important that you should pass up something just because it has a few flaws, even those that may seem major. After encountering many specimens that run the gamut from new to used/abused/landfill, I have combined my other hobby of scale modeling with calculator collecting to aid me in restoring the treasures I come across during my hunting and trading.
More often than not, a thorough cleaning may be all that is needed to make your latest find a presentable display piece. I have seen several of my specimens that appeared to be damaged far worse than they actually were just because they were covered with dirt and grime. Remember, calculators are operated by hands and you have no idea where those hands might have been! For surface cleaning I recommend Formula 409, Fantastik or a weak ammonia solution. NEVER use solvents of any kind for general cleaning as most calculator cases were manufactured from styrene, an easily molded, soft plastic that is readily attacked by petroleum based chemicals. Solvents do have their place in my restoration practices though. (More on this later).
One product that is safe to use to remove adhesive and other sticky substances is GOO-GONE, available most everywhere. This product is oil-based and should not harm most plastic cases, however, be cautious around screen-printed lettering as some fading can occur. Use this sparingly and only in those areas where the adhesive is stubborn.
When you have thoroughly wiped down your calculator and removed adhesive, etc. inspect the seams, grooves and other recessed areas where dirt and gunk have built up. To clean these areas, a Q-tip soaked in cleaner can be used. I like to take this procedure one step further by using a TUPPERWARE orange-peeling tool, this is a yellow-handled thingy that looks like a toothbrush without bristles and is flat like a screwdriver on one end. It is great for scraping out the seams and grooves without causing damage to the surrounding plastic. When things are really gunked up I disassemble the calculator and wash the case halves in a mild soap solution. I know disassembly is not for everyone but It is not that difficult if done carefully in a quiet well-lit area. Most calculators are held together with two to four screws and come apart easily. There are exceptions to this rule as some are press-fitted with locking tabs. For this I use a CASE-CRACKER that I purchased from my local electronics repair shop. I think you can also find them in electronics supply catalogs. I NEVER use a screwdriver or any other flat metal tool to pry the cases open, these tend to inflict more damage to the plastic.
Earlier I made mention of my use of solvents in the restoration and repair of damaged plastic. The solvent of choice for this procedure is Methyl Ethyl Ketone, or M.E.K. for short. This stuff eats styrene like acid and can cause extreme damage if not applied properly. M.E.K. is a component of most lacquer thinners and is highly volatile. It can be purchased at most larger home centers and hardware stores such as Home Depot. DO NOT use lacquer thinner or acetone as a substitute, these leave residue and evaporate much too slowly.
Once I have done my basic clean-up I then inspect the calculator for structural defects such as: case cracks, scratches, gouges, engraved ID (identification) numbers, etc. all of which can be removed or lessened to a great degree by using some of the following techniques:
1. CASE CRACKS.
2. SCRATCHES, GOUGES and ENGRAVING.
For the smooth, glossy finished type cases I use the M.E.K. to soften the plastic then smooth with my fingertip. After this I let the plastic dry overnight then I use varying grits of wet/dry sandpaper WET to smooth out the finish.
Use 400 grit paper first to remove the heavier defects then switch to 600 grit paper to begin the polishing. Once you have obtained a smooth yet matte finish switch to an abrasive liquid kitchen cleanser like SOFT SCRUB or BON AMI, apply sparingly to a soft slightly damp cotton cloth and rub gently in a circular motion. You will begin to notice a change in the appearance of the plastic as it gets smoother. After this step then switch to COLGATE brand toothpaste (the cheap white kind) applied in the same manner, this time buffing rapidly. Once the finish is near original then use a small amount of silicone type car wax. AUTOFOM is my personal favorite, FINISH 2000 is also a good choice. Remember, use only small amounts of these abrasives, the plastic is soft!
3. DEEPER SCRATCHES and GOUGES.
4. DISPLAY LENSES.
5. CHROME and GOLD TRIM.
6. FACEPLATE SCRATCHES.
7. THE FINAL TOUCH.
BATTERY PACK REPLACEMENT.
Other calculators may have their batteries sealed directly in the chassis, in this situation opening the case and replacing them is usually all that is necessary. At times your calculator still may not operate with fresh power, it has been my experience that most electrical problems are due to broken or corroded wires. The older ni-cads get, the more susceptible they become to leakage and this in turn can damage the internal components of the calculator. (Be careful when dealing with leaking batteries as they do contain acid and heavy metals, dispose of them as you would any other hazardous waste). Cleaning the inside of a calculator that has suffered leakage is as simple as washing with a solution of baking soda and water (About 2 tablespoons to 8 ounces of water). Do not immerse the affected electronics in this solution, just generously moisten a lint free cloth with it and wipe/blot the surface of the component, then wipe/blot with a dry cloth. Let the part sit for a time to allow extra drying. Inspect the battery connector wires for breaks and repair as required. I use a 25 watt fine point soldering iron and light gauge solder, be careful with the hot iron! Keep it in contact with the connection only long enough to flow the solder into the joint, heat destroys electronics quickly!
If you are not familiar with soldering, practice on some 24 gauge braided wire, not your prized Commodore! Most replacement batteries can be found at RADIO SHACK or other electronics supply houses, and even come pre-wired in two, three or four packs of AA size. Another source for odd type batteries is THE BATTERY STORE at www.thebatterystore.com. I found the replacements for my HP41CV there. Great place!
Well I hope my modest experience gives you some ideas to assist you in restoring these past marvels of modern science, I realize that I have not covered all the possible refinishing and repairing problems you may encounter but these are as varied in number as the amount of calculators there are to collect and I can only write so much! Remember, start out with your restoration and repair work slowly, begin by using a calculator that you can afford to experiment on. I have the advantage of being a fine-scale modeler for the past 20 years and have used these techniques while assembling 1/48th scale aircraft kits with the occasional car kit thrown in. Just practice until you gain confidence enough to tackle that HP65 with an engraved ID number and hazy display window!
HAPPY COLLECTING - BOB!
© Text & photographs copyright Nigel Tout 2000-2013 except where noted otherwise.