commodore 1540

here is the advanced scientific calculator model 1540 from 1976.

this mains desktop model with a ten digit vacuum fluorescent display appears to be functionally identical to the sr-1800. indeed, both have the same chipset, the ghu-03a and give the same results.

the small buttons are a bit fiddly to use considering the size of the machine, the layout is slightly peculiar and the equals button would benefit from being bigger.

the display is clear and it uses 12 digits internally. results are similar to the sr4148r and it shares many of the same features, like the radians dot, exponent scaling and two memories.


on the left here is the main chip for the whole calculator.