Toshiba DT01ACA100 won't spin after power surge

[gameboybin]

these are not sensitive to neither pcb nor heads, so it should not click like that. But clicking after pcb swap clearly points towards preamp damage. and with a damaged preamp anything could happen, this is why i always advised checking preamp after a suspected OV, without trying to power the drive with a replacement pcb.
There's one thing worth noting, namely that there are 2 types of pcbs these drives came with: OA90377 and OA90381, the main difference being the motor controller. However, i still don't think this is the issue, as the drive cloned just fine with H0.

another possibility is that the overvoltage did not kill the preamp, but only triggered uncontrolled write current on channel 1, damaging the content on that surface. This could be checked by putting the orig head stack back and disabling H1. I would also check the patient MHA in a donor, where it cannot do significant harm (disabling one head at a time).

Sorry pepe! How can i check Preamps in PC3000!

[Hardcore Games]

Usually the 12V is used for the drive motor as the logic board uses 5V and 3.3V to operate the CPU etc.

[pepe]

i can also imagine a scenario where the supply voltage does not trigger the tvs but too high for a preamp to work safely, but this is also only theory.
The breakdown voltage of an 5V tvs is given as 6.4-7V for 1-10mA in the DS i checked, but for a decent current of several amps (where the fuse breaks) it goes even higher, to 8-9V, which can be way too high for reliable working of a preamp, so anything can happen there, even if it survives. I recall the WD drives with 701335 and similar PCBs, where the -5V supply feedback path broke at a via due to oxidation and voltage started to rise, drive began clicking at -8-9V but did not get damaged, then as the voltage went on rising, it broke later.

The only way to make sure is checking the signal with a scope, which is not an option coz almost nobody uses such thing... so we are guessing based on the symptoms.

[pepe]

Sorry pepe! How can i check Preamps in PC3000!

you can't. see my previous post i left open for some time in my browser and some replies were made in the meantime i haven't seen earlier.
put the patient MHA in a working donor and check heads enabling one at a time. You may also check it by measuring preamp pins to GND with multimeter in diode mode and compare readings to a good one. This should reveal big problems but not an ultimate way.
But, as i wrote in my prev post, it is not even sure the preamp got damaged, it might only have malfunctioned during the overvoltage period.

pepe

[gameboybin]

Sorry pepe! How can i check Preamps in PC3000!

you can't. see my previous post i left open for some time in my browser and some replies were made in the meantime i haven't seen earlier.
put the patient MHA in a working donor and check heads enabling one at a time. You may also check it by measuring preamp pins to GND with multimeter in diode mode and compare readings to a good one. This should reveal big problems but not an ultimate way.
But, as i wrote in my prev post, it is not even sure the preamp got damaged, it might only have malfunctioned during the overvoltage period.

pepe

i got it! lets eleminate the possibilities one by one

Can you point out where the Preamp pins are? I will measure them

[pepe]

at the MHA connector of course

[fzabkar]

Can you point out where the Preamp pins are? I will measure them

Please upload a clearer photo of the HDA section of the PCB.

Attachments

HDA.jpg (113.19 KiB) Viewed 10318 times

[pepe]

not this one but on the hda.

[fzabkar]

not this one but on the hda.

I use the PCB to probe the connector because I never know which is the preamp ground pin. On the PCB, all grounds are connected to screw holes.

Also, I use the PCB to identify the +5V and -5V supplies.

[gameboybin]

at the MHA connector of course

Wait. do you mean i need to measure them inside a running drive it self?

[pepe]

yep, that's fine, but ultimately we want to measure preamp, not the pcb... preamp gnd is usually connected to chassis, so it is safe to use that as reference. And to compare it is also just fine. While knowing where power rails are is useful for starting with those, signal lines are also informative when comparing.
edit: this was intended for Fzabkar, you posted the above while composing this msg...

no need to remove the MHA, just measure those contacts with pcb off...
patient vs. donor.

[gameboybin]

Can you point out where the Preamp pins are? I will measure them

Please upload a clearer photo of the HDA section of the PCB.

Here you go

[fzabkar]

+/-5V rails

You could measure the resistances at the connector on its own. Then measure those same resistances at the PCB, and compare the readings with the PCB attached and detached from the HDA.

Attachments

[gameboybin]

Well, thanks everyone for helping me out

I managed to solve the case. Very strange way and very strange solution
I managed to read head 01 by swapping 500GB Toshiba heads over. Turning off head 0 in NV-RAM (I have tried this before with 1TB donor. Didn't work)

All data is recovered

[pepe]

hm, glad to hear... Crazy though...
btw, have you tested the orig head stack in a donor?
pepe

[gameboybin]

hm, glad to hear... Crazy though...
btw, have you tested the orig head stack in a donor?
pepe

Not yet. i will test it tomorrow and tell you the results

[gameboybin]

hm, glad to hear... Crazy though...
btw, have you tested the orig head stack in a donor?
pepe

So i did swap back to the original patients heads. It has damaged head 1. After turning off head 1 in NV-RAM the Drive start spinning fine. And can read head 0 data
The strangest thing is that. All donor drives need at least 1 head turn off to be able to read the other head. So they both will not work at the same time. If head 0 then no head 1. Vise versa

[fzabkar]

I would try the original PCB. Just remove the shorted diode and flow a blob of solder over the fuse. Maybe there is some weirdness in the read channel??