Service Forum

[sudonimity]

When I try to read the eeprom i get "Error: Eeprom not accessible".

I noticed that the owner of the laptop removed the battery so now it asks for the password to boot, without the option to view the BIOS in user mode, aka Locked.

I have read that in this mode the eeprom is not accessible, so I resorted to the full 6 wire solder job that bypasses the need for a computer to be turned on. still getting "Error: Eeprom not accessible".

To double check my soldering, I ran the iTester.exe, and that is returning correctly, 1-1,0-0,1-1,0-0,... I then checked the voltage between gnd-sda, gnd-scl, both at 3.4v. But still "Error: Eeprom not accessible".

Aany ideas to what I might be missing.

[victor]

The eeprom is very "accessible" and the program will read it just fine as it is. Remove all those unneeded wires and let only the SDA and SCL in place, connect the GND wire to VGA out shell.
When is soldered in system, the eeprom must be powered only by the laptop or you risk to damage the motherboard.

If you need support then post some pictures, this is the only way we can help you.
_________________
Victor Voinea
ALLservice HQ, Romania.

[sudonimity]

when i remove the other wires the itester.exe nolonger respondes with the sda in. and obviously still nothing with the dump software. (cannot do pictures right now, no camera)

[sudonimity]

sorry had a bad connection, iTester.exe is working now, but still no accessible.

[Zack]

Same problem here. After 4 hours of trying to read my T22 ATMEL chip, still get "Eeprom not available!". I only have two wires on the 14 pins chip, SDA and SCL. The ground is connected to a RAM bracket. I know that my SDA and SCL are correctly connected to the chip because iTester runs fine. My wires are a bit long between the com port and the chip (~12-13 inches), maybe this is the problem? Normally, serial communications aren't affected by the cable length like parallel communications.

I'm using the method with the two 2.2k resistors and the two zener C5V1 diodes.

Should I use the other circuit with the RS232 chip?
_________________
Zack

[victor]

Ok, first off put the GND wire to VGA out screws/nuts, its safer there.

Now, it seem that the resistors have higher value than 2.2K, or the COM connector is wired wrong, or the port is not doing it so well.
In conclusion:
1. Check the resistors with a multimeter.
2. Check the connector's pins assignment.
3. Try another computer with a better com port.

And keep the wires coming from eeprom to the interface as short as possible, that is the TTL part of the circuit.
_________________
Victor Voinea
ALLservice HQ, Romania.

[sudonimity]

OK, I

-dubble checked my resisters. both at 2.2K
-dubble checked my com wireing, all correct
-cut my cables down to ~1"

All the same, the tester works, but the program cannot find an eeprom to read. I got fed up with this, the customer this is for had waited long enough so I just ordered a new chip with the password set to blank.

[victor]

Well, I can help you only if I see pictures of your interface and connenctions. I am not a clairvoyant, I am sorry.

As I said:

1. The interface is not good or wrong connections to serial port or eeprom.
2. A "weak" port for SIPROG.

Those two above are the only reasons your setup is not working, no matter what you think or believe...

Why replace a good working chip? A chip with a "blank" password may not solve your problems as the pattern is not the same even for the same model.
Is the worst possible idea, you'll get a surrogat eeprom with the same serials/UUID and MAC sold buy those guys to many people, your client risks to have a laptop with same credentials as one used to commit crimes on the internet, this is just an example.

Moreover, the guys who sell you a chip are simply using our programs that you seem to can't make them run.

I am sorry I could'n help more, but is not up to me.
_________________
Victor Voinea
ALLservice HQ, Romania.

[Zack]

Hi Victor,

Here's a picture of my reader setup. The wires were not connected at the time of the picture, but I've identified them.

When testing, I'm connecting each of the 4 serial port wires directly to the serial port of another laptop, and I manually connect the SDA and SCL to the ATMEL chip while someone else is pressing ENTER on the other laptop.

I always get "Eeprom not available!". I know my SDA and SCL wires are correctly connected because when there aren't, I got another error message.

It's not very clear on the picture, but the GND is connected to the RAM bracket that is soldered on the motherboard. This way, I can have a shorter ground wire. I've tried a longer wire connected to a VGA port screw, but the result was the same.

Link to the picture:
24rf08reader.jpg
_________________
Zack

[victor]

Ok, but where's the serial connector? I want to actually see where the pins you numbered there go..

I hope you do not solder those two SDA and SCL wires directly like I see in the picture. The interface must be attached to eeprom only at read time after laptop is on and POSTed!
Or you may use 2 needles (probes) or use two pair of wires, one pair coming from eeprom and the other one from the interface.
_________________
Victor Voinea
ALLservice HQ, Romania.

[Zack]

[victor]

You must use a DB9 female, and don't improvise.

How do you connect the wires to eeprom? Don't tell me you solder them after turning on the laptop or keep them in place with your bare hands.
My advice was to use two probes or to solder permanently a separate pair of wires, if that rings a bell.

Good luck!

(Robbyrobot, you were right!)
_________________
Victor Voinea
ALLservice HQ, Romania.

[Zack]

[Robbyrobot]

This one amazes me too, Victor. Just for the record, this is what my SIPROG looks like:

It's easy to put the whole thing into a serial plug, and use alligator clips to connect to the micrograbbers on the chip pins (SDA, SCL) and to a proper ground. If I didn't have the micrograbbers, I'd probably attach the alligator clips to needles and use that method of connecting to the chip.