Seagate hard drive and monitor problem

[searchingheaven]

I had a Seagate ST3250AS 320GB HDD SATA. It was working perfectly until oneday when i took it out to clean the cabinet from inside and change the fan. After that it is just not working, it is not detected in the POST and the PC does not start when it is connected to the system.{I have the operating system on another IDE drive}. When i remove the Seagate the computer starts. I have a lot of data on it which is quite important? Will anybody help me out in this?

Another problem that i have is with my monitor, an HCl HCM780M 17' CRT. Its black colour is showing up as dirty green. All other color reproduction is perfect. It seems to reduce a bit when brightness is reduced to minimum. Whats the problem with it?

[Faun]

For monitor issue:
Help!! My monitor's display fogged out....

[pimpom]

Since the hard disk prevents your PC from starting up, one of the power supply lines on the hard disk probably has a short-circuit. For someone with experience in electronics, it's possible to test this with a multimeter. Testing is easier with a PATA drive but can also be done to a SATA drive using a 4-pin to 15-pin adapter.

The yellow wire on a 4-pin connector is the 12V line and the red one is the 5V line. The two middle black wires are ground.

If you know someone with experience in electronics and a multimeter (preferably a digital one), ask him to test the resistance between the power input pins and ground. If the resistance is zero or nearly so, you have a short.

If you can have this test done, report the result and we'll see what we can do.

[searchingheaven]

Yes i have got it checked and he says that there is a short. He also checked my hard drive on my system in the following manner:
He kept his hand on the drive and started the system. He felt something and told me that the motor is dropping current after spinning for 1 second. Is there anyway to recover the data? He also said that it can work if u change the power chip at the back{of exactly same make, model}. Should i do it?

[pimpom]

It may be possible, not only to recover your data, but also to have your HDD working as before. But let's get one thing straight first: Since I can't check your HDD personally, I can only give you guidance and cannot guarantee the result. You have the option of taking the drive to a Seagate service center, but if it's under warranty and they decide to give you a replacement, you won't get your data back. The choice is yours.

Did you see the "power chip" mentioned by your friend? The shorted part is probably one of the TVS (Transient Voltage Suppression) devices. This is a small black rectangular block about 4-6 mm long, soldered to the circuit board at both ends. The exact size varies from model to model and sometimes from batch to batch.

This device protects the rest of the electronics by absorbing momentary spikes in the power supply rail and sometimes gets shorted permanently due to heavy surges. But there's always the possibility that other parts of the circuit are damaged, in which case it's unlikely to be repairable except in a specialised lab.

If the faulty part is the TVS, replacing it with a good one of the same type should cure the problem. But make sure your friend knows what he's doing. If you have some doubts about his capability, I suggest you don't let him do anything.

I wish I could help by checking it out myself, but I'm a long way from Jamshedpur.

[searchingheaven]

Firstly thanks a lot for taking pains to go through this. It is 4 years old, so no warranty. Now he is the only chance i have. Where will i get this TVS?

[pimpom]

The TVS is probably not easily available in electronics parts shops except perhaps at places like Lamington Road in Mumbai, Lajpat Rai Market in Delhi, etc. The most likely source for you would be an old hard disk. It doesn't have to be the same model as yours.

First, check which line (12V or 5V) is shorted. Then remove a TVS from the corresponding line from the old drive. Before soldering it onto your hard disk, test it with a multimeter to make sure that it's not also shorted.

Sorry about the sporadic response. My internet connection is really really erratic these days - has been so for more than a month now. I've called the BSNL people at least half a dozen times and they respond quickly, but they have not been able to isolate the cause. We've firmly established that it's not on my side, but they just can't pinpoint the culprit.