HP31E Missing Pin

[teenix]

(03-13-2021 12:12 PM)AndiGer Wrote:  Hi Tony,

Look into this thread - especially last post:

https://www.hpmuseum.org/cgi-sys/cgiwrap...read=24353

Tony Duell mentions pin 8 is the power supply pin on all small IC chips inside a spice. The C models have this IC pin directly connected to PSU / battery to retain RAM content.

Andi

Thanks Andi

Being a power pin the chip (ROM) may have been damaged by not powering up properly while other logic signals are fed to it.

The pin is broken at the point it exits the plastic case so will be hard to attach a wire to.

If anyone knows, I take it that carefully un-clipping the 6 internal plastic retainers (3 on each side of case) will allow more access to innards.

cheers

Tony

cheers

Tony