HP-65 goes on hold after reading a card

[albertofenini]

Thanks Tony,

I need to figure out how to compare more than two channels since our scope has only two ...
How are related the length of the program to the length of this waves ?

I understand this : there are two channels on the head named A and B
from the head these go into the sense amplifier at pins HAC (connected to CA) and HA
and HBC (connected to the CB) and HB

The sense amplifier is responsible for handling the motor functioning and amplify those
signals before these get to the hybrid in the pins WA, EB, RA and RB

WA and WB should be for Write channel A and write Channel B
RA and RB should be for Read Channel A and read Channel B
but what is WE for ?

What documentation could we read (easy to understand) to better understand the functioning of this ?

For instance, if W or R signal is dirty, how can we track it back to the head and try to troubleshoot ?

Thanks a lot for your patience and your help, take care

(11-16-2020 09:22 AM)teenix Wrote:  I attached an image explaining the data flow while writing a card.

You can see the data on WA WB is between the head switch going low and then high as the card enters and exits the mechanism.

The RA RB data would be similar for a read.

cheers

Tony

(11-16-2020 09:07 AM)albertofenini Wrote:  Thanks Tony,

do you mean that if we put a probe on the HDS pin we should see the flows of data
and see where it stops ?

Do we need to check also RA and RB ?

take care !