Just some musings on the problem.
My son had one of the early Gameboy game systems which were notorious for bad lines of pixels on the LCD. Sure enough, after about six months there were 10 lines out. I discovered that applying pressure to the front of the case would remedy the problem briefly - thus I thus deduced that the solution would be to apply more pressure to the back of the connector on the LCD panel. I disassembled it, cut a narrow strip of double sticky foam tape and placed it over the elastomeric connector on the LCD to increase the pressure on the contacts. I then reassembled the case and turned it on. It worked perfectly for about 5 minutes and then one or two of the LCD columns would fade out intermittently.
I attributed this to the stiffness of the flexible ribbon connector and thought that heating the Gamboy to approximately 130°F would soften the plastic ribbon and allow more intimate contact with the LCD panel. I turned the oven to low and allowed it to preheat, placed the Gameboy on an insulated cookie sheet and waited for the oven. As I waited, I envisioned my son holding a 10” x 18” ¼” sheet of plastic in his hands and crying – not a pretty picture.
I decided to try a less extreme method of incinerating my son’s Gameboy and placed it in my car parked in the sun for several hours while making sure the game was not in direct sunlight. That solved the problem and the system has worked perfectly for the last 9 years.
I realize the difficulty of disassembling an HP-48 but leaving it in a car for a few hours may solve your problem. Here are a few caveats before you do this:
1. Remove any plug in cards – less risk.
2. Start in the morning with the car cool and leave the calculator in its case to provide insulation which will limit the rate of temperature change.
3. The manual states that the storage limit for the HP-48GX is 149°F but does not mention if this is with or without batteries – I would remove them if it were my calculator.
4. Do this at your own risk!
