Service Forum

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

I'm getting the error "eeprom not available" when trying to read the 24rf08ct chip on my t23.

before I go any further I wanted to check - on step two of "dumping the password" it says "press F1 during the startup to enter the BIOS."

Well I can hit F1 and it says "entering BIOS" but then it prompts me for this darn password before I can actually GET INTO BIOS.

Am I even on the right track with all this? Is THIS the supervisor password or a power-on password?

Regardless, I think my jig should be working. Here's the results from itester:

SDA = 4.7V high and -0.76 low
SCL = 4.4V high and -0.72 low

w/o any circuit attached I get 11.1V and -11.1V coming straight off the serial port.

I measured the resistors @ 2.16 Kohm and the box for the diodes says "IN4733A 5.1V Zener Diode"

I'm *sure* I built the circuit correctly:

http://farm3.static.flickr.com/2317/2125469530_37b4950682.jpg?v=0

SO, what am I missing?

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

I checked the voltage on pin 8 (SDA) and pin 10 (SCL) of 24rf08ct and both read 3.211V

I checked the connection from pin 6 (GND) to the screw hole where I'm grounding and they are connected with no resistance.

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

Open a new tab and take a look at the following image:
http://farm3.static.flickr.com/2157/2125705106_d2eb3de220.jpg?v=0

Now you can imagine you hooked up your multimeter and measured impedance between the following points:
A-E = .8 Ohm
B-F = .7 Ohm
C-G = .7 Ohm
D-H = .8 Ohm
D-I = 2.18 K
C-K = .8 Ohm
B-K = 2.19 k
A-K = 6.5 MOhm
A-I = 6.5 MOhm (six and a half mega ohm? looks like OL to me...)

So that looks good I think? Except the serial cable I cut open isn't exactly the greatest. But I can only compare to what I have around they shop - and they're all measuring just under 1 ohm

sigh... you know funny thing. This laptop didn't USED to ask for a password? But the only "error" it gives me before the password is 0271 about check date and time settings.

I don't know. I'm almost 100% I've built and connected the SIPROG correctly. I'm missing something else...

victor · S.F. Boss Joined: 07 Mar 2004 Posts: 2581 Location: Staff

One thing you didn't mention about the itester: How about "SDA/SCl out" and "SDA in" values, are they switching together?

Drawings look correct, but I am not sure about the COM port, that in your 2nd picture is the male or female connector?
_________________
Victor Voinea
ALLservice HQ, Romania.

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

ah, victor - THANK YOU for the reply. I think it's amazing how much work you've done to help others in the forum. I hope I can turn out to be another one of your success stories (I have read MANY!)

I'll post pictures of the pc board (front and back) for you tomorrow. But I don't think they'll be any easier to follow. They are laid out pretty much exactly like the diagram.

"SDA/SCL out" and "SDA in" values track as described in many other threads - 0 and 0, then 1 and 1.

In the second drawing the diagram of the 9-pin connector is as if you are looking "down the holes" of the female connector (the end that plugs into my computer). What I've done is take a standard serial cable and cut off the male end - located the wires that correspond to the pins in the diagram - and soldered them directly into my circuit.

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

http://farm3.static.flickr.com/2108/2127118820_85c758e90e_b.jpg

It's hard to see in the backside of the image - but there are NO shorts between the ground return line on CTS and DTR. Also, those copper wires soldered into SDA, SCL & GND are bent down - normally the point stright up and so I can alligator clip to them. But if there's and specific test points you like me to ohm out - just call 'em. I'm super in to re-double checking my work. Thanks again victor!

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

I failed to notice earlier in itester that SCL is inverted...

SDA looks correct,

itester 0 = -0.77V
itester 1 = 4.72V

SCL is inverted,

itester 0 = 4.41V
itester 1 = -0.73V

I've verified this behavior on three computers.

I tried r24rf08.exe dump.bin /x
and got a "circuit not found or bus error"

Is it not strange that my SCL is backwards!?

victor · S.F. Boss Joined: 07 Mar 2004 Posts: 2581 Location: Staff

OK, I was afraid of that. The db9 connections are wrong (mirrored). For example "A" in your picture goes to the other side (pin5 -GND) and so on.

Good luck!
_________________
Victor Voinea
ALLservice HQ, Romania.

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

flippin' great

I'll let you know...

clayg · Nou Venit Joined: 20 Dec 2007 Posts: 8

finally:
http://farm3.static.flickr.com/2039/2127119437_5aa9ff1f3e_o.jpg

although I have to say - I'm confused as to how I mis-interpreted this diagram:
http://farm3.static.flickr.com/2199/2127106057_3092b2538c_o.jpg

Maybe there is some "rule of thumb" about DB9 connector diagrams of which I'm unaware?

Anyway, here's my dump:
http://www.mediafire.com/?byepbgyhoxy

ANOTHER VICTOR SUCCESS STORY!

BTW, my password was XPBIOS

victor · S.F. Boss Joined: 07 Mar 2004 Posts: 2581 Location: Staff

It is your success not mine..

Well done, and btw..I know the feelings when you see the OK on screen Smile

Happy Christmass to you and yours!
_________________
Victor Voinea
ALLservice HQ, Romania.

waltergr · Nou Venit Joined: 11 Feb 2008 Posts: 1

Hi all,
does anybody have the pinlayout for this ic? I need the pin no for scl and sda I have only the layout of the 8sop
Thanks

victor · S.F. Boss Joined: 07 Mar 2004 Posts: 2581 Location: Staff

Pin 5 = SDA
Pin 6 = SCL

Pin 1 has a mark on its edge.
_________________
Victor Voinea
ALLservice HQ, Romania.