WESTERN DIGITAL WD20EZRX Not reading Lower Tracks

[ROb]

Hello
I have replaced faulty Heads in WESTERN DIGITAL WD20EZRX with good ones.
The drive started perfectly but its Not reading / Slow reading the Lower Tracks, i mean up to 50 % initial LBA is giving problem. Rest 50 % i.e the higher LBA i could image w/o any problem.
My question is
Is it due to alignment or something to do with "MicroJog"
Help appreciated
Thanks

[jono-ats]

Was the drive dropped?

[ROb]

Was the drive dropped?

No the drive was't dropped for sure is the feedback of customer.

Maybe the new heads have a big microjog difference from the older ones.

Ideally you would aquire the set of heads for replacement with close microjog value from the original heads.

You can also try to tweek the microjog value settings/adaptives to a medium value of the old heads with the new ones with a firmware tool like wdr.

Cloning with de or ddi might also help.

new heads have no or minor difference of MICROJOG value. Tried using Average value still there is no difference.
Wondering what could be the reason.
Thanks for the above replies

[ROb]

Thanks Splidit for suggestions
yes i tried reverse in DE same problem persist
Slow reading fix also tried did not work
Please note that upper 50% LBA is perfectly working and managed to image perfectly
Only Initial LBA are slow specially in Head 1 and 2
Thanks Again

[labtech]

Sounds like media damage of some sort.

[ROb]

I shall try this and revert to you by tomo
Thanks

[jono-ats]

I would experiment with lid alignment / spindle zenith adjustment, even though the service tracks are normally wide enough on this model that lid positioning normally isn't a consideration.