When a treasure of retrotechnology fails to work, the pure subsequent step is to have a go at repairing it. [Adam Wilson] discovered himself on this place when he acquired a 1974 Sinclair Cambridge Scientific calculator, and his progress with the machine makes for an attention-grabbing learn.
First up is one thing of worth to all outdated Sinclair fans, he’s discovered an answer to the unique battery connectors being liable to failure. A few components stocked by RS can be utilized as replacements, which ought to save numerous Sinclairs with crusty connectors.
Saving the connectors ought to have mounted the calculator, however solely served to disclose that it had an digital fault. Some detective work traced this to the ability provide, which is a small switching circuit. The 1974 chip and related coil had each failed, which slightly drew the undertaking to a halt. A second repair-or-spares Cambridge Scientific was sourced, and by good luck it occurred to have a working PCB. So [Adam] obtained a working calculator, and we hope he’ll succumb to the temptation to shoehorn in a PSU from 2022 to get the opposite one working.
Anybody inquisitive about this barely uncommon calculator should take a look at our teardown of one.