Spildit wrote:
So, are you able to read SA modules/tracks on your ebay drive with the damaged drive pcb without any ROM flashing ?
Yes. I did a short test, reading with a VSC the track -1 head 0...and returns fine the header of the Module 0x1...which holds the modules hosted on the SA. I've stopped here the researches, don't want to push the donor, because it has that hole patched and I'm afraid not getting dust inside.
Spildit wrote:
Can you read your donor drive in that condition (with patient pcb) on a different head (not head 0) ?
Tried only on head 0, but it should work fine on all the heads. The problem should appear as we take distance from the track -1 and the read head doesn't stay on the same track with the write head. The adaptives handle that.
Quote:
When heads flying above track in the middle of a platter, centers of reading and writing head will be above center of the same track and drive can read and write on the same track without moving heads. But if, for example, heads move toward OD, centers of reading and writing heads will not be above the same track, one of the heads will be far offtrack (sometimes several tracks aside). Such a difference between centers of reading and writing heads called MR Offset. MR Offset is not a constant it varies from track to track; it also can be negative (for ID) and positive (for OD). MR Offset depends of track location and track width. Another parameter called PLO Delay or Read-Write Delay. It shows difference between Read Gate and Write Gate appearances. On different tracks PLO Delay will be different for Write Gate. As we know each head has unique parameters and MR Offset and PLO Delay also will be unique for each head. Drive stores averaged MR Offset and PLO Delay for each head at least for each zone in special tables called Adaptive tables or just Adaptives (adaptives also include some other critical parameters). Adaptives may be stored of the platters in special area called System Area or SA.
So if my be stored on AS..you don't need them to read SA. You need the head map etc..which on the same model..should be the same.
Spildit wrote:
And on the damaged drive with ebay pcb, did you try to read using a different head ? And with modified head map on RAM ?
No...I know where you point...but I'm sure 100% that I'll get the same result as with the original PCB. It's clear...with the patient's PCB I can access the SA of the donor...not having any clicking, without any touch to the firmware.
My final diagnostic: dead-PREAMP.
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