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Hard drive activity light issue

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First post, by GrampaGotTheKeys

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Odd problem, I'm curious if anyone might be experienced with the issue.
The situation is I installed a new SCSI hard drive into an old Macintosh SE, the drive works great so I thought I would go ahead and attach an LED to the appropriate pins.
I tested the pins with a multimeter and they receive 3.1v but only during boot and shutdown and so any LED connnected only flashes for a split second.
Is the drive just incompatible with the way the Macintosh uses the SCSI connection?

The model of the drive is a 80MB IBM WDS-380S:
4Dd4C3U.jpg

Reply 1 of 3, by Vynix

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Hm no, the LED should flash whenever the drive is seeking, it is very well possible that during normal use, the drive will not give enough power to the LED to make it light up.

Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]

Reply 2 of 3, by GrampaGotTheKeys

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Vynix wrote:

Hm no, the LED should flash whenever the drive is seeking, it is very well possible that during normal use, the drive will not give enough power to the LED to make it light up.

That's what my multimeter reports showing 0.00 volts through those pins when seeking

Reply 3 of 3, by Vynix

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This indeed strange... I once dealt with a newer HDD (IBM UltraStar 9ES "Draco" / DDRS-39130) that exhibited the same issue: no power on the LED pins during a seek.

I tried every jumper combination on it, nothing. I eventually threw in the tovel and hooked the HDD activity LED to the SCSI card's LED connector, so now it lights up whenever there is activity on the bus. Now, I don't know if a Macintosh SE has such a "SCSI bus activity LED" header on the logic board or not, with that in mind, I'm afraid that there isn't a solution to that.

Proud owner of a Shuttle HOT-555A 430VX motherboard and two wonderful retro laptops, namely a Compaq Armada 1700 [nonfunctional] and a HP Omnibook XE3-GC [fully working :p]

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