HP97 Card Reading

[dbhp67]

Hi,

I have just got a really nice 97 which is working really well. However it seems to have restored batteries, but I have no idea how old they are.

When I try to read a card it works fine when on the power supply, but won't read when only on batteries. Everything else works, the printer, the display etc when on batteries - just not the card reader.

I assume the batteries must not be providing the correct power. But apart from a Multimeter and basic electronics is there an easy way of checking the battery pack against some spec?

If not, I will be looking for a replacement pack!

Many thanks
DB

[teenix]

(02-16-2021 01:55 PM)dbhp67 Wrote:  Hi,

I have just got a really nice 97 which is working really well. However it seems to have restored batteries, but I have no idea how old they are.

When I try to read a card it works fine when on the power supply, but won't read when only on batteries. Everything else works, the printer, the display etc when on batteries - just not the card reader.

I assume the batteries must not be providing the correct power. But apart from a Multimeter and basic electronics is there an easy way of checking the battery pack against some spec?

If not, I will be looking for a replacement pack!

Many thanks
DB

It could be the batteries in poor condition, however, the card reader uses less power than the printer, so it seems a bit odd that it doesn't work and the printer does.

The HP-97 charger cannot supply the power required to run the card reader/motor however it might be supplying just enough to add to the (I'm guessing) poor battery and allow it to work.

Does the low battery LED light during card reader or printer operations?

cheers

Tony

[dbhp67]

Nope. No battery light.

It just gives an error when using battery only. I have left it on charge now for a few hours more and will try again.

Thanks

DB

[Dave Britten]

(02-16-2021 09:28 PM)teenix Wrote:  It could be the batteries in poor condition, however, the card reader uses less power than the printer, so it seems a bit odd that it doesn't work and the printer does.

The HP-97 charger cannot supply the power required to run the card reader/motor however it might be supplying just enough to add to the (I'm guessing) poor battery and allow it to work.

Does the low battery LED light during card reader or printer operations?

cheers

Tony

That was my thought too, but the printer working fine seems to imply that it's not the battery or a simple contact issue. My 97 (which now needs a new idler gear, argh!) was lighting the low-battery lamp when printing, but it turned out to just be weak contact inside my modified battery pack. The lamp never came on when reading/writing cards, though.

[teenix]

Totally unsure on this, but the card reader has analog amplifiers inside the sense chip so maybe they are a bit sensitive to voltage variations when reading.

As the card write is more digital in operation, does the card write ok on battery only? You could write on battery only then reconnect the charger after the write to see if it reads back ok.

The 97 also has additional circuitry attached to the sense chip (not really sure what it does) but I suspect compensates for the 5V supply instead of 3.75 for the 67.

cheers

Tony

[[kby]]

Does the card reader sound significantly different on batteries only vs. batteries with AC?

How does the failure to read manifest itself?-kby