Sharp EL-5800 Scientific Calculator

Got this machine since a long time ago, in dismantled state and waiting to be repaired.

Today morning I decided it was time to empty the dismantled machines drawer, so I started with this one.

The only issue was the battery compartment that had the oxidation in the power switch/battery terminal assembly. The machine was sold as non working.

After cleaning all the parts to remove the battery electrolytes products, it was time to repair, test and assemble it.

Single chip machine: HD36125

Heavy battery corrosion has damaged the positive terminal.
I have these battery miniature 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 is soft  and started to melt when soldering.
And I was too lazy to dismantle the whole set in order to be able to do a clean soldering.
Still it is mechanically and electrically working fine now, despite the ugly looks.

After power on.
Current consumption = 62mA

All digits lit.
Current consumption = 80mA

 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.