MY HDD BARRACUDA 7200.11 500GB ST3500820AS FIRMWARE SD35
MADE IN THAILAND, ( WAS ATTACHED TO SEAGATE EXTERNAL FREEAGENT DESKTOP)

Steps Tried

1.> Verify it is stuck in busy state, downloaded victoria 4.2 and ran a PCI scan and the busy was blinking occasionally.

2.> Verify the serial interface cable is working properly

CA-42 Clone Chinese, Blue, Red,Green White and Yellow, Ripped open the USB end connector and found that
Green -> TX
Red -> RX
Blue-> GND

Connected the cable to front USB connector of Desktop pc and it detected the USB -> UART and installed the driver from the cdrom which came with cable, the driver was Nokia CA-42 USB, no chip was mentioned.
Connected TX with RX for loopback test

Ran putty with 38400,8 N 1, none for hardware flow

the loopback was successfull as the letters were getting echoed back on screen and when i removed the loopback the characters were not getting echoed.

3.> Inserted a thick paper between PCB and Hdd contacts and
Connected TX from Cable to RX of HDD, Connected RX from Cable to TX of HDD and GND of cable to GND of HDD
tried pressing CTRL + Z ( uppercase) and CTRL + z ( lowercase) .....no response

Power cycle the system + HDD, no success

Tried swapping the RX and TX cables , No Success

Removed the paper between the PCB and HDD and Powercycle the system+HDD
the putty ( terminal ) window was displaying (LED: 000000CC Faddr.........) every 1 min
tried pressing CTRL + Z ( uppercase) and CTRL + z ( lowercase) .....no response

, I would like you comments
1.> Since i am getting LED message in terminal window, does this means my serial interface is properly connected
2.> Do I need to add power ( 3.3v) to other pins

6.30PM
measured the Voltates
GND and TX - 3.2 Volts
GND and RX - 3.1 Volts

The Power to HDD is coming from PC's SMPS, and USB is connected to Same PC, also I have connected the USB Cable GND to HDD GND

When i Put a insulation between PCB and HDD, i.e. for Motor Pins or Other Pins ( rectangular set) , I am not getting any data from the HDD to terminal

Only when i remove the insulation i keep getting
LED: 000000CC FAddr:0024900D from Hdd every minute.....

7.10 PM
As per Suggestion Tried below

1) Loosen all screws and lift PCB and remount the PCB
2) Loosen all screws so far that the head connector is dissconnected.
3) Tighten only the head connector screw so that it get's contact again
4) Supply power to the disc, wait until you get the LED: blablabla message
5) Keep sending Ctrl z ( z in lowercase) had also tried Z in uppercase
( i kept sending for 3 minutes but i could not see the prompt at all )

the prompt keeps on alluding me.......

I have the same problem: the terminal session doesn't work.

I have a Barracuda 7200.11, 500Gb, model ST3500320AS made in Thailand, with the "bad" firmware SD15. The drive doesn't get detected, even prevents a Gigabyte motherboard from booting at all when connected to the first SATA port. I didn't check, but I guess it's the busy problem.

My laptop has a com port, so I used a serial cable, and connected RX, TX and GND to the drive following a diagram I found. I checked the connections using a cable tester, And I tried to short RX & TX to see if I have loopback. I'm using Windows 7 on my laptop, so I downloaded the Hyper Terminal 7 trial (I was used to it from using it in Windows XP). The settings I used are 38400-8-N-1 and no flow control.

When I power on the drive with the connection enabled, I can't see anything on the terminal. I can type, and I get looback, but no command has any effect (I tried Ctrl+z and a lot of other things).
I also never receive any message on the terminal window.

I even tried with the PCB without the hard disk, with the same result.

Update to my problems:

I tried reversing the RX and TX cables, but all I got was trash. Sometimes a screen full of random characters, happens too when I try to write something. I guess I was connecting the RX and TX leads ok.

I tried too with another computer. I digged a serial port bracket to connect to the motheboard of my desktop PC, and I got it configured. To try another software, I downloaded RealTerm. I got the same results as with my laptop & HyperTerminal.

As I had another hard disk with the same problem (an ST31000340AS) I tried that other hard disk with the exact same result.

I looked at some tutorials, and I tried putting some tape in the connector for the heads, and leaving only the spindle motor connected, same result.

I'm getting out of ideas. Perhaps it doesn't run with a standard serial port? The USB serial ports everyone is using has something special my "real" serial ports doesn't have? I need to recover the data on those hard drives...

I have found this page here that shows the schematics for connecting a serial port from a Seagate hard drive to a PC's COM port:
http://hddguru.com/content/en/articles/ ... schematic/
I guess what I'm trying to do doesn't work, I need that USB to serial cable or I have to make that thing on the schematics.
Can anyone confirm this?

Ok, at last I found my mistake.

The serial port on the hard disk works with TTL voltages 0V & 5V, while the RS232 port uses -12V & 12V.
I hope I didn't fry the hard disk serial ports. Tomorrow I'll buy a RS232 to TTL adapter and I'll try again.