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

[Vtile]

(09-05-2016 08:15 PM)Claudio L. Wrote:  

(09-05-2016 01:25 PM)Vtile Wrote:  I have not much time atm. to delve into your finds, but as a quick scan of data it seems that if connecting testpads R66 and R67 should fix electrical HW problems of the WP issue.

I read your post, now with a tiny bit more time and tough. My first intuition seems to be correct. For me ir seems like ( said above) you can permanently disable the writelock, by jumpwiring the pads R66 & R67 to fool the calculator hardware that the card is inserted, but not locked. This is the easy fix if it works, but only partial solution since it disables write protection permanently.

Based on your tests and the datasheet I found, it's clear that either R66 or R68 is the common wire, the other one is card detect. That leaves R67 for WP.
Write protect goes active when it's unlocked per your probing, and because when the card gets inserted R66 is always in contact with R68, doesn't matter whether you connect R67 to R66 or R68, either should get the job done.

Oh, nice that you can confirm it from another route. R66 is better it saves copper!