HP97 The journey begins

[teenix]

Hi all,

The time has finally come to start repairs to a HP97.

I always wondered, saying (a HP) or (an HP) ???
I say H as Haytch, not Aycth, so a HP sounds better, tomaytoes and tomartoes I guess

Anyway, the unit is almost totally dead. Just the low battery light on and the card reader motor running continuously. The printer motor is "ticking" suggesting that it is trying to turn on then immediately off again.

This will take some time to get going one way or another but will be an interesting challenge.

I asked a little while back about opening up a battery case to replace batteries, but no answers so not sure if it has been done

The two case halves that I have were glued together, but not continuously around the join. With some small inwards pressure on one half, I was able to insert a small flat bladed screw driver into a gap and widen it slightly. I then used a 2nd driver to open it a bit further, then alternatively shift them bit by bit further along the widening gap. I carefully continued this along the long case edge trying not to distort it and I could hear the glue spots break apart as I went. Eventually it separated.

One of many questions to follow I'm sure, but there are 2 battery terminals on the battery pack. Can anyone please verify that the terminal near the centre is the +ve and the other nearer to the case edge is the -ve? I want to power the calculator directly with my bench power supply, but don't want to fry anything.

I'm sure they will be needed, so I ordered some O-rings for the card reader from the US for a few $ and they arrived in short time.

When the dealer finally opens again ???, I am buying myself a late Xmas present, a Rigol MSO digital oscilloscope which should help things along.

cheers

Tony