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HP 50g SD card reader problem - Printable Version

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HP 50g SD card reader problem - JJB299 - 08-21-2010

The card reader on my 50g always thinks the card is "write protected" and gives an error when trying to format the SD card or paste into the SD card directory.

So.. I tried to fix it. Unsuccessfully.

But I have some really cool pictures of the inside of the 50g.

Does anyone know what pins or wires need to be connected/disconnected so a card reader disables the write protection?
I can send images if needed.

I've tried a few different configurations without success (and without frying the calculator, so I guess that is a small victory).


Re: HP 50g SD card reader problem - Vieira, Luiz C. (Brazil) - 08-22-2010

Hi, JJB299;

please, forgive me if the questions seem silly, I do not mean to:

1 - have you tried with different Secure-Data cards?

2 - what is the size of the SD card you are using?

3 - Brand?

4 - Have you used the SD card elsewhere?

I just want to figure out possible reasons hence applicable solutions. I used many cards in my HP49G+ and HP50G (three units), all of them from 256MB to 2GB (this one checks only 1GB, discussed here some months ago). Apart of not being able to 'see' more than 1GB (I successfully tried two different SD cards, different brands), I had no problems formatting/writing with the HP50G.

One 'last minute' possibility: have you tried to update, if applicable, the O.S.?


Luiz (Brazil)

Edited: 22 Aug 2010, 12:42 a.m.

Re: HP 50g SD card reader problem - Vieira, Luiz C. (Brazil) - 08-22-2010


about the 'write lock': you could try with an empty SD card adapter and safely measure which terminals are shorted while opening/closing the 'write lock' switch.


Luiz (Brazil)

Edited: 22 Aug 2010, 12:46 a.m.

Re: HP 50g SD card reader problem - JJB299 - 08-22-2010


I found the problem!
To answer your questions, yes I've tried all of those points.
The card is a lowly 256MB, but the card wasn't the cause.

The card reader assembly inside of the calculator had a bad contact. I was focusing on the upper portion of the card reader near the SD card contact. But the problem was a contact on the lower left corner of the card reader (when facing the back of the calculator with the case open).
I'll try to recreate it here (view with Courier font):

|| | | | | | | | | | (top pins into board)
| |
| SD card reader |
~~~~~~~~~~~~~~~~~~~~~ (break)
| |

* = bad contact near bottom of calculator.

I couldn't manage to solder it on, since the original contact was adhesive and the solder wouldn't stick. I just tried to hold it against the board contact with padding.
After that, the card formatted and wrote just fine.

Hope this helps someone else with the same problem.
P.S. Not for the faint of heart (look for how to disassemble a 50g on Y**Tube). It looks painful, but the screen went back on fine.