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HP-67 1805S02334 [RA and RB noisy, doesn't read but writes]
11-20-2021, 08:27 PM (This post was last modified: 11-20-2021 09:14 PM by albertofenini.)
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HP-67 1805S02334 [RA and RB noisy, doesn't read but writes]
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

Edoardo & Alberto
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HP-67 1805S02334 [RA and RB noisy, doesn't read but writes] - albertofenini - 11-20-2021 08:27 PM



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