ST3100640AS Endless HM

[DNC_Scotty]

Hi everyone,
I've got a ST3100640AS that is a recertified drive in the lab. Everytime that I put in some heads that I think are compatible I get a little life on the first power up. The second time I get an endless HM HM HM on the terminal. I copied the ROM to a new PCB and still have the same issue. I am not sure where to go from here. The media looks good. I do not see any particulates that would make me think media damage. Below is a sample output from the terminal.


Reset
8192k x 16 DRAM

F>Reset
8192k x 16 DRAM
GALAXY4D - 1_Disk S-7A 12-08-06_16:49

Buzz HM SFI
!
ERR Read Rsv Trk Dft List

F> Code - 47 Track 15E22.0.001 Sns 001
F>Reset
8192k x 16 DRAM
GALAXY4D - 1_Disk S-7A 12-08-06_16:49
HM HM HM HM HM HM HM HM HM HM HM HM HM Reset
8192k x 16 DRAM
GALAXY4D - 1_Disk S-7A 12-08-06_16:49

Buzz HM HM HM HM HM

[northwind]

It's most likely heads.

This is a 4 platter drive, so there could be media damage to any of the 7 remaining surfaces you can't look at.

Remove the heads and inspect them under microscope. Are they dirty?

[DNC_Scotty]

They have a white coating to them under the scope. So that is definitely part of the issue. Any recommendations on what to clean with? Currently I am using 99.9% isopropyl alcohol and some small brushes. But they are leaving behind fibers so I think I need different brushes.

[DNC_Scotty]

And research has answered my questions, thanks for the help!!!

I found a local clean room supply company that has what I need.