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HP-67 - 1909S02534 - Card reader advice requested
01-27-2020, 11:30 AM
Post: #5
RE: HP-67 1909S02534 - Card reader advice requested
(01-27-2020 11:26 AM)teenix Wrote:  
(01-27-2020 09:47 AM)albertofenini Wrote:  Hello Everyone,
after a bad moment in our lives with the loss of my father,
we re-opened our lab and started to work again on our toys.
Yesterday we restored an HP-67 that was in working condition but showing some wear,
you can see some pictures here :
HP-67 1909S02534 - Full restoration
However, the card reader, although rebuilt, it keeps giving an error message.
This is what RA and RB looks like :

What would you suggest to do ?
Thanks for helping us out !!!

Hi Alberto,

Indeed a sad time. Memories are forever.


The only thing I can see is the timing of the signals looks skewed. They should overlap as in the attached read image.

The idea of this approach is to provide a self clocking mechanism for more reliable data transfers.

Why it would be skewed is a mystery, but it might just be oscilloscope timing.

Does it write ok?



Thanks Tony,
they look a little dirty too so we were thinking of capacitors to be replaced,
we haven't tried to record and read on another unit, which is a good hint,we'll try it out
and keep posting !

Thanks for your words, Alberto

Edoardo & Alberto
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RE: HP-67 1909S02534 - Card reader advice requested - albertofenini - 01-27-2020 11:30 AM

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