Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
June 12th, 2021, 2:38
yes
but I accept the result because it changed from 20 ohm to 80 ohm
I considered this as an indicator
June 12th, 2021, 13:46
I confess that I don't understand the results. A resistance of 80 ohms still seems too low, but I have no working drive to compare.
June 12th, 2021, 14:44
lets ignore the 80 ohms value and look that the changes is an indicator that it is really the preamp shorted on the patient drive, Because the 20 ohms value is the same when the two multimiter props touched each other and now on the donor drive it is different value.
June 12th, 2021, 14:51
I want this confirming to know if i must continue in this issue or I must stop
June 12th, 2021, 14:59
It does appear that the patient's preamp is shorted, but that would mean that the donor's preamp is measuring 60 ohms. That doesn't seem right either???
June 12th, 2021, 16:50
fzabkar wrote:It does appear that the patient's preamp is shorted, but that would mean that the donor's preamp is measuring 60 ohms. That doesn't seem right either???
this depends on the type of multimeter and the set measurement limit.
June 13th, 2021, 4:45
What resistance do you measure if you reverse the probes (on both patient and donor)? It may be that there is a Schottky diode which is affecting the reading.
http://www.hddoracle.com/download/file.php?id=249&mode=view
June 13th, 2021, 13:03
Here are the readings
patient drive:
4 ohms in both props direction (normal and reverse) and after subtract the the resistant of the multimeter wires
donor drive:
normal: 63 ohms after subtract the the resistant of the multimeter wires
Reverse: no value when the measurement limit is set to 200 ohms and
2.3k ohms when the measurement limit is set to 20k ohms
June 13th, 2021, 13:10
Ah, that's a lot better. The diode (D) was being forward biased by your meter, resulting in a low reading. When it is reverse biased, the readings make sense. Sorry about that, I should have picked that up earlier.
That said, your preamp is dead. :-(
June 13th, 2021, 13:27
so it is not DIY case and need more advance works
I assume that it need replacement of the preamp in clean chamber
June 13th, 2021, 14:06
Yes, it requires clean room work.
June 14th, 2021, 6:30
I would like to thanks all who participates in this topic
and special thanks to fzabkar for his effort and patience
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