11-20-2021, 08:27 PM
Hi Everyone,
this is about asp HP-67 with what looks like a noisy card reader
While CA and CB looks fine, both when reading and both when the calculator displays a 0.00
RA and RB show a noise immediately after power on
When reading a card you can still see the the reading among the noise
We have already replaced the sense amplifier with no improvements
We have already swapped the CPU board with a known working one with no improvements
What could it possibly be ?
Any suggestion will be greatly appreciated !
Take care !
[EDIT]
I have also uploaded some WA and WB captures
As a matter of fact the captures show no noise and a good wave on WA and WB
both when reading and when writing (switch W/PRGM in Write position)
The so written card can be successfully read on a different working HP-67
Pictures here : HP-67 1805S02334
this is about asp HP-67 with what looks like a noisy card reader
While CA and CB looks fine, both when reading and both when the calculator displays a 0.00
RA and RB show a noise immediately after power on
When reading a card you can still see the the reading among the noise
We have already replaced the sense amplifier with no improvements
We have already swapped the CPU board with a known working one with no improvements
What could it possibly be ?
Any suggestion will be greatly appreciated !
Take care !
[EDIT]
I have also uploaded some WA and WB captures
As a matter of fact the captures show no noise and a good wave on WA and WB
both when reading and when writing (switch W/PRGM in Write position)
The so written card can be successfully read on a different working HP-67
Pictures here : HP-67 1805S02334