Hello,

I've got a broken Samsung HD502JI (part of external USB drive).

12 V line resistance is 0 Ohms on the PCB, measured with PCB taken out.

I've bought HE502IJ with "visually same PCB", same 88i8826D-BAM2 controller, same SH6125B (which appears to be be burnt on the original PCB), other minor components are really similar.

PCB revision is the same, BF41-00205B, REV05.

I was ABOUT to try to simply switch PCBs, but I've discovered HE502IJ is rated 7200 rpm, and HD502JI is 5400 rpm.

Is is possible that the speed is being controlled by some kind of firmware, or there must be some difference in the circuit I haven't noticed? It both are the same speed, and and it's just the marketing?

What do You recommend? Maybe I should try to move the firmware from the damaged hdd to the new pcb?

TVS Diode FAQ:
http://www.hddoracle.com/viewtopic.php?f=100&t=86

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