HP 50g & SD Cards: Performance, Format, Notes

[JDW]

Vtile,

Thank you for the resistor size confirmation.

I removed all batteries, including the button cell, and then I waited a few minutes for the capacitor to fully discharge. I then probed the PCB again.

When I put one probe on Ground (where the black wires solder to the PCB, coming from the batteries), and put the other probe on the SD card slot metal body, I get a beep, confirming that the metal frame of the SD card slot is definitely Grounded. So without any batteries, that point is absolutely confirmed.

R67<->SC Card Slot Metal

With the SD card REMOVED, I put a probe on the round pad on the R67 trace, and put the other probe on the SD card slot metal, and I do NOT get a beep. (I also probed between Ground and the R67 pad, and no beep either -- no surprises there since the SD card body is grounded.)

With the SD card INSERTED and UNLOCKED, I put a probe on the round pad on the R67 trace, and put the other probe on the SD card slot metal, and I do NOT get a beep.

With the SD card INSERTED and LOCKED, I put a probe on the round pad on the R67 trace, and put the other probe on the SD card slot metal, and I do NOT get a beep.


R66<->R68:

With the SD card REMOVED, probing between the R66 pad and R68 pad does NOT give me a beep.

With the SD card INSERTED and UNLOCKED, probing between the R66 pad and R68 pad gives me a beep.

With the SD card INSERTED and LOCKED, probing between the R66 pad and R68 pad gives me a beep.


R66<->R67:

With the SD card REMOVED, probing between the R66 pad and R67 pad does NOT give me a beep.

With the SD card INSERTED and UNLOCKED, probing between the R66 pad and R67 pad does NOT give me a beep.

With the SD card INSERTED and LOCKED, probing between the R66 pad and R67 pad does NOT give me a beep.


R68<->R67:

With the SD card REMOVED, probing between the R68 pad and R67 pad does NOT give me a beep.

With the SD card INSERTED and UNLOCKED, probing between the R68 pad and R67 pad does NOT give me a beep.

With the SD card INSERTED and LOCKED, probing between the R68 pad and R67 pad does NOT give me a beep.


NOTE: Beep = True = Connection, No Beep = False = No Connection

Thoughts?