Hewlett Packard 48GX Repair

The HP 48GX is on the higher end of HP's graphing calculators. Released in 1993, the HP calculators are known for their RPN format. RPN stands for Reverse Polish Notation, in which the operators follow their operands, instead of the other way around. Operator refers to the thing that affects the numbers- it adds, multiplies, divides, etc. The operands are the numbers that are having something done to them- they are being added, multiplied, etc. To see how RPN works, we can use the example of adding three plus four. In standard notation, the mathematical statement ‘adding three and four’ would be written like this: 3+4. In RPN, however, the statement would be written like this: 3 4 +. This notation was introduced by Arthur Burks, Don Warren, and Jesse Wright in their 1954. It was used by HP calculators during the 1970s and 1980s, and is commonly found in stack-oriented computer programming languages. The appeal of this notation is that it uses very few parentheses, making it useful for programming.

The 48GX has a faster than normal clock frequency, more RAM, and a memory card slot. The X suffix on the name indicates that this calculator can have expanded RAM (memory) and ROM (software application). The model number of an HP calculator is usually in one of three places: below the screen, in the top right corner, or in the top left corner.

Processor: Saturn 1LT8
Memory: 128 KB RAM, 512 KB ROM
Display: 131 x 64 pixels, monochrome LCD
Dimensions: 7.05 x 3.11 x 1.1 inches
Weight: 0.55 lb.
Battery: 3 x AAA battery
Connectivity: Serial, proprietary infrared
CPU clock frequency: 3.68 to 4 MHz
Memory clock frequency: 2 MHz
On-board ROM: 512 KB
On-board RAM: 128 KB
Maximum additional memory for expansion card port 1: 128 KB
Maximum additional memory for expansion card port 2: 4 MB (128 KB addressable at any given time via bank switching)