Sharp EL-5800 Scientific Calculator: sturdy built and reliable machine
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11-19-2016, 05:56 PM
Post: #1
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Sharp EL-5800 Scientific Calculator: sturdy built and reliable machine
Got this machine since a long time ago, in dismantled state and waiting to be repaired.
Today morning I decided it was time to start emptying the dismantled machines drawer, so I picked the one at the top of the pile. I have another model with similar build documented here. The only issue with this 1976 machine was the battery compartment that had oxidation in the power switch/battery terminal assembly. The machine was sold as non working. According to the Instruction Manual, this calculator takes two AA dry batteries, or the optional Ni-Cd battery pack EA-18B and the Ni-Cd Recharger model EA-17E. Look to Katie Wasserman site for the manual. After cleaning all the parts to remove the battery electrolytes products, it was time to repair, test and assemble it. ![]() Single chip machine: Hitachi HD36125 Display Futaba 9-ST-12 ![]() ![]() ![]() Keyboard assemblage. Note the metal spring interconnecting the front metal face plate with the keyboard metal frame assembly. ![]() ![]() ![]() The keyboard PCA snaps over the keyboard membrane and two screws fix it securely in place. ![]() Heavy battery corrosion has damaged the positive terminal in the battery compartment. I have these miniature battery terminals at hand, so have trimmed one of them and soldered it to the original remaining terminal. Could not do a clean job though, as the plastic assembly is soft and started to melt when soldering. I was too lazy to dismantle the whole set in order to be able to do a cleaner job. Still it is mechanically and electrically working fine now, despite the ugly looks. ![]() (continued) Jose Mesquita RadioMuseum.org member |
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11-19-2016, 06:12 PM
Post: #2
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RE: Sharp EL-5800 Scientific Calculator: sturdy built and reliable machine
After power on. Current consumption = 62mA
All digits lit. Current consumption = 80mA ![]() Main PCA folded and in place. ![]() Cover installed. It snaps at 10 different points (latches). It takes just one screw. ![]() ![]() Forensics test - asin(acos(atan(tan(cos(sin(9))))))result: 10.7508 ![]() Error condition on display: SQRT(-2): All zeros and all decimal points lit. ![]() Despite being boxy, it is still a nice looking machine. ![]() This is the package I got. ![]() ![]() Jose Mesquita RadioMuseum.org member |
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