Service Forum

[communique]

Hello to everyone ,my first post, and I hope you will tell me if I am going about things the correct way.
I have made the driven board and the Db9 connector.
I have attached it to the com port and started itester.
Checked inverter box as for driven circuit
Both are on 0
Click connect
The readout is
SDA goes to 1 (constant)
SDA/SCL 0 then alternates to 1 and back to 0 every five seconds as the help suggests.
Have I made the board correctly?
I didn't use the batteries during the test was that right or wrong?
Thank you in advance.

[victor]

Hi,

Use the batteries
Both values must switch 11-00-11 together, or the interface is wrong. Also check the SDA and SCL logic level using a voltmeter.

And do the test with SDA and SCL on air, do not connect them to the eeprom!
_________________
Victor Voinea
ALLservice HQ, Romania.

[communique]

Hi Victor, Thank you for the reply.
I connected the batteries
Both switching together now 11 00 11
Checked SDA with my old analogue multmeter ( I think I should come out of the dark ages and buy digital one)
SDA value 1 = 3.75v 0 =0.75v 700ohms
SCL value 1 = 3.75v 0 = 0.75v 700ohms
Batteries are not new so I think the voltages are probably a bit low?
Does this mean I built the interface correctly?
Or incorrectly?
If its correct I can try to extract the eeprom dump, which brings me to another question.
I will use the needles to connect to the eeprom and many posts say use an earth connection other than the earth leg on chip,such as the vga screw,and from there to the ground on the interface,is this correct?
Thanks for all your help I have learned a lot from reading the posts in your forums.

[victor]

Ok, the batteries are low, replace them!

Cool. Give it a try
_________________
Victor Voinea
ALLservice HQ, Romania.

[communique]

Hi Victor,Thank you,thank you,thank you.
Can't say how happy I am that it worked.
I forgot to buy new batteries but the older ones did the job.
Took about 10 tries before I got the dump mainly I think because I was attaching the earth wire first instead of last!!!!!
Beind a mechanic I should have remembered the rule - negative lead-remove first - fit last.
I had a batch of 14 passworded motherboards all now clear.
All had the same password too so I only had to take one eeprom read.
I will send you the .bin file.
Once again many thanks.
Kevin.

[Mimamau]

Am I right in my assumption that I have to connect SDL to SCL for itester to work? Then my interface seems to be ok...
Without connection SDA stays on 1 and SCL alternated between 1 and 0.

[bob]

No, SDA and SCL must be on air, don't connect them to the I2C eeprom or you may risk to corrupt something.

[Mimamau]

Not to the EEPROM, I mean to each other.
If they mustn't be connected to anything, I have done something wrong.

[bob]

Then you forgot to connect pin MAX232 pin 11 or else