FossilRock

Where exactly? Mind you, I am not saying that the CP2102 does not support the "lower" TTL levels (I simply DO NOT know for sure that ) , only that I cannot find (and I doubt you were able to ) this particular spec on the provided datasheet. Page 14 / Section 8. Voltage Regulator / Table 10. I'm currently working on a soft-o'scope utilizing an Arduino board for the measurements. Which may yield some useful results for the thread. Back to the original problem; the drive appears to have died. The motor doesn't appear to spin up now and makes a slight, repetitive hum/buzz sound.

I decided to start from scratch. I put the circuit board back on (without the contact inhibitor) and was surprised to hear it spin up and then start clicking followed by it spinning down. Is this a symptom of the controller or the drive itself? Seagate 1.5 Clicking.mp3

The CP2102 Data Sheet shows that the output is 3.3v. I also have another drive identical to the problem drive (other than the serial number, they are the same) that works fine. I've tested just the circuit board (powered) for both drives and I get the exact same results. When unpowered it appears to be in loopback mode because everything I type (alphanumeric) shows up in HyperTerminal. I've also tried Putty with similar results.

I wasn't trying to measure TTL levels, I was merely seeing if there was anything measurable on the pins. I read in another portion of this thread that you should be able to get the CTRL-Z to work even if the drive is not powered. I tried that and all it produced was a → (right arrow). Turning power back on produces no output. What makes you think the adapter is a dud? Everything seems to work as it should, just not the communication with the HDD.

Ohm / Volt meter (9v range) -- GND <-> RXD = 3.3v .... GND <-> TXD = 0.79v Adapter was bought off eBay. I've switched the TXD & RXD on the adapter (easier) which should have the same results as on the HDD. I've got an Arduino Nano, I'm going to see if I can rig something up that will give me some feedback to see if the signal from HyperTerminal is going through. Added: Here's a post within this thread that shows a different model of the adapter being used.

I purchased the USB to TTL converter shown below. It appears to function correctly as far as the pinouts go. Shorting RXD & TXD echos my typing in HyperTerminal. The voltage pins (3.3 & 5) are accurate as well. I don't think there are any issues with the device. I have a card isolating the pins as described, with the board still attached to the drive. I've wired the device to the HDD both ways (RXD <-> RXD / TXD <-> TXD & RXD <-> TXD / TXD <-> RXD) to ensure I didn't have it backwards but there's no difference. My drive is a Seagate Barracuda 7200.11 1.5TB. I'm powering it with an external Sata HDD power adapter. The drive spins up and continues to spin for about 35 seconds and then spins down. To the best of my knowledge, I've done everything as described. I've also used a USB to RS232 (DB9) cable with the same results.

I've been struggling with this Seagate issue for a month or more with no success. I've read the 'sticky', I've followed the steps, but I can't seem to get a response in HyperTerminal when connected to the drive. I purchased the USB to TTL converter shown below. It appears to function correctly as far as the pinouts go. Shorting RXD & TXD echos my typing in HyperTerminal. The voltage pins (3.3 & 5) are accurate as well. I don't think there are any issues with the device. I have a card isolating the pins as described, with the board still attached to the drive. I've wired the device to the HDD both ways (RXD <-> RXD / TXD <-> TXD & RXD <-> TXD / TXD <-> RXD) to ensure I didn't have it backwards but there's no difference. My drive is a Seagate Barracuda 7200.11 1.5TB. I'm powering it with an external Sata HDD power adapter. The drive spins up and continues to spin for about 35 seconds and then spins down. To the best of my knowledge, I've done everything as described. I've also used a USB to RS232 (DB9) cable with the same results. I would appreciate any assistance in figuring out why it won't communicate with the drive. Maybe the device just doesn't do as claimed. I'm at a loss. Thanks in advance, Fossil