September 6th, 2016, 21:20
September 6th, 2016, 23:00
Spildit wrote:Hello there !
First of all you can't repair the surface of a drive. If the surface have defects and/or the heads are failing then it's time to replace the drive.
September 6th, 2016, 23:06
September 7th, 2016, 2:52
Spildit wrote:You might get away with free or pirated tools but up until now i've never saw anyone reporting sucess using those "shaddy" tools, on the contrary. For example for MAXTOR there is a free software to manipulate firmware called HDD Repair 2.0 but all the people that i know that have tried to use that ended up with completly dead drive, so .... don't say that i didn't warn you !
September 7th, 2016, 21:49
Spildit wrote:You might want to start by reading some research on VSC like the following :
September 8th, 2016, 1:23
Spildit wrote:Ok then. Good luck and let us know if you manage to make any progress with your drive repairs.
September 8th, 2016, 8:21
Old Tech wrote:If I could find a way to extract the required tables from the good drive, can I swap them with the bad drive?
September 8th, 2016, 9:43
Old Tech wrote:I have been an electronics technician and a computer technician for a long time and I have thought about building my own interface, like the PC3000 and writing my own software to communicate with the drive. It would help if someone had already started such a project.
September 9th, 2016, 20:56
data-medics wrote:I think you are vastly simplifying this task in your own mind. Before you should even consider trying to make your own tool, you'd need to spend about ten years working with an existing tool so you actually have some clue as to what these tools do and how complex they are. Then you'd need to study several different fields of programming and engineering. Then you'd need to either spend the next two hundred years reverse engineering every vendor specific command for every hard drive out there or find someone willing to just openly share all this (no one will, they've got too much invested in it).
There is a reason it takes an entire team of engineers and programmers in Russia to produce a tool like PC-3000. To think that one "old tech" is going to pull it off by himself is either pomp or just ignorance.
September 9th, 2016, 21:22
Spildit wrote:Please do read my article about translator here - http://www.hddoracle.com/viewtopic.php?f=46&t=1402 . It should answer your question.
September 10th, 2016, 0:22
Old Tech wrote:I have also traced the entire circuit of a hard drive and I have no difficulty understanding what is going on in the circuit. Back in the old days of computers, in the late 1970's and '80s, I used to replace heads in the field and re-align them using a special disk that had a track dedicated to a signal that could be seen on an oscilliscope. You aligned the heads by watching the amplitude and vertical evenness of the signal.
Old Tech wrote:There was a suggestion that you add a free-wheeling diode to the relay on the board. If the power inputs to the relay coil are isolated from the rest of the circuits on the board, there would be no need for such a diode at 12 volts. There are MOVs used on such boards anyway to absorb transient spikes.
September 10th, 2016, 15:21
September 15th, 2016, 2:49
fzabkar wrote:Diodes should always be used to protect the switching transistor. Even at 12V, very high back-emf voltages are induced when the relay's coil current collapses. Snubber diodes are just standard practice for any good engineer.
September 15th, 2016, 3:09
fzabkar wrote:Most of WD's VSCs are documented within the scripts packaged with TREX. This factory tool is all over the Internet, including the HDD Guru files area. That would be a good start....
BTW, here is an "IDE Grabber" that you could build:.
September 15th, 2016, 3:24
fzabkar wrote:Old Tech wrote:I'm an electrical engineer who has plenty of experience as a component level tech. In fact I worked on those same drives (eg Control Data, Ampex, Fujitsu) way back in the 1980s. I well remember those cat's eyes patterns. I wrote my own head alignment program (30 words of machine code) for a Data General minicomputer. This allowed me to use regular software packs instead of expensive CE packs and disc exercisers. Those were fun times.
....BTW, I would love to see your reverse engineered circuit diagram. Information like that is very hard to come by.
September 15th, 2016, 20:58
Old Tech wrote:This is actually a case of data acquisition and storage. I only scanned your link but they send the output to a printer port and it's not clear what they are doing with it. I did notice a picture of what appears to be the trace of a multichannel osciliscope, and they can get pricey.
I was thinking along the lines of capturing a good slice of data and written a program to analyze it.
September 15th, 2016, 21:04
Old Tech wrote:Perhaps the relay is driven by a chip that has protection built in. Perhaps the diode is located in a location that is not obvious. I don't know.
September 16th, 2016, 2:30
fzabkar wrote:ISTM that the relay is controlled by 5V logic via a simple NPN transistor.
September 16th, 2016, 2:31
fzabkar wrote:It has already been done for you. The Grabber includes software that captures the IDE traffic.
September 16th, 2016, 17:10
Old Tech wrote:fzabkar wrote:ISTM that the relay is controlled by 5V logic via a simple NPN transistor.
I was researching this question but I have been under the weather the past few days and it's giving me a headache.
Suppose you use a 2N2222. It has a forward current of 1 amp and a reverse breakdown voltage of 40 volts minimum.
The relay is a Rayes RS-12 with a nominal operating current of 12.5 milliamps and a coil voltage of 12 volts.
The question is this...can the induced voltage spike be high enough to exceed the 40 volt reverse breakdown voltage of the 2N2222 transistor?
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