Samsung ST1000LM024 won't spin up with different heads

[msurgeon]

This drive had damaged heads. Replaced heads with virtually identical model and HDD P/N. Drive will not spin up. Donor won't spin with patient heads either. Replacing original heads in each allowed both to spin up normally. Is there something obvious I'm missing here. Thanks for any input.

[DCDL]

If a Samsung fails to spin the heads are incompatible. Check the preamp on startup using terminal and you can match them easier.

[msurgeon]

Thank you.