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Calculators: Handheld: Litronix 1102 (aka constant/percent)
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| Size (approx): |
77mm
x 155mm x 20mm (w,h,d) Weight 128g excluding batteries |
| Power: | 6.0V from 4 x AA sized batteries. It accepts an adapter (6V DC, 0.25 watts) through a socket on the left side in the middle. A large warning sticker on the battery cover door reminds you of the importance of correct battery insertion, with a diagram. |
| Case: | Angular design made from a two piece case in patterned black and tan coloured plastic. The top is dominated by an inset silver painted metallic panel that has the brand name embossed out, unpainted. It also has the model number printed in white text. Below this is a flat and flush red plastic display filter that gives a bright but limited angle viewing of the digits. The two switches are inset in their own section with embossed lettering: on/off to the left, constant to the right. The shaped keys are quite proud but have short travel with a loud click. |
| Display: | 8 digit red LED with bubble lens, with a ninth digit for negative and overflow indicators |
| Features: | 4 function calculator with percentages and selectable constant. RPN logic. |
| Age: | 1974 |
| Manufacturer: | Assembled in Malaysia, Litronix Inc., Cupertino, CA, USA. Serial number 176897 is on a sticker inside the battery compartment. |
| Comments: | Tall and slim design with a very solid feel to it. The large upper panel is needed for the battery compartment as it is so thin. The archaic logic is let down by lack of recovery, input overflow and the negative zero bug. The original case is soft brown plastic with a flip over top flap and front popper closing. |
| Components: | 1 x cpu: unmarked, 28 pin DIL, 0.6" width
grey ceramic 1 x IC: LBC 1090, 18 pin DIL, 0.3" width, grey ceramic 3 x 3 LED display modules with individual bubble lens 1 x transistor 0 x diodes 3 x capacitors 4 x resistors 1 x transformer Astec AA1561 |
| Boards: | The main cpu board (6509-006) is attached by two melted plastic pillars that cannot be unhitched without permanent damage. It is connected to the keyboard assembly by 11 stiff wires |
| Construction: | Remove the two screws from the rear that are half hidden by the rear information label. Then gently prize the top edge away and pop the lugs by pushing out the front section in the battery compartment. There are two more lugs on the bottom edge. Be careful as damage may easily result. |
| Logic comments: | The (CE) key is used to clear the last number entered and the (C) key will clear the calculator |
| Overflow on number input is not suppressed inputting a ninth digit will create an overflow that is not recoverable | |
| There is switched constant (K) on multiply and divide only | |
| Negative numbers are shown with a “-“ to the immediate left of a number, travelling into the far left (ninth) digit thereby allowing full eight digit negative numbers | |
| Overflow shows the result and "E" in the far left (ninth) digit and is not recoverable | |
| Divide by zero shows "0.0000000" and "E" in the far left (ninth) digit and is not recoverable | |
| Used in isolation the (%) key will divide by 100 | |
| It uses Reverse Polish Notation logic (RPN): to do 3-4 key in (3)(+=)(4)(-=) to give "-1" | |
| It suffers the negative zero bug: key in 1-2 with (1)(+=)(2)(-=) to give "-1" the add one by (1)(+=) to give "-0" |
