HP97 The journey begins

[teenix]

(04-16-2019 12:09 PM)Robert VM Wrote:  Does anyone has an idea why these oscillator components were put on the printer board and not near the ACT itself?
Likewise the card reader board and display board have some of the power supply components.

I wondered that myself, there is plenty of room for the oscillator components on the cpu board. It seems they wanted the printer to be in circuit for the calculator to function properly which seems odd.

The printer state isn't tested during the microcode initialization process but if you hit any key that tries to start the printer when it is disconnected, the microcode will stay in a permanent loop until the cpu "sees" the print head is home. This effectively disables the calculator and makes it appear dead.

It makes sense to keep some of the power circuitry near the components that they will control.

cheers

Tony