Sounds of the Miniscribe 8450

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Miniscribe 8450
Country of Origin: USA
Introduced: 1986
Interface: ST-412HP (RLL nominal)
Capacity: 40MB
Form: 3.5 HH (1")
CHS: 770 / 4 / 26
LZN: 771
WPC: 65535
Track-track: 11.3ms
Linear access: 25.7ms
Random access: 39.4ms
Rotational: 3600RPM
Media: Metallic, inline TF heads
Disks: 2
Actuation: Linear rack and pinion stepper
Feedback: Track zero sensor
Lift/Lock/Park: None
Brake: Dynamic
Service life: Unknown
Related models: 8212 (1 disk), 8225n (1 disk, RLL, A for ATA, X for XTA), 8425n (S for SCSI-SE, A for ATA, X for XTA, F for performance), 8438 (RLL), 8438F (RLL, performance)
Failures: Many
Settings: aioinc.ddns.net/HOST/TH99/h/tx...
My thoughts:
If this drive were of better quality, it would almost be a marvel of miniaturization. This drive is like a 3650 condensed even further, into the chassis of an 8000 series. It's really too bad that these drives were total junk, as the performance is not the worst, and a low cost 3.5" 40MB drive this early on could have sold very well. Unfortunately, even this nearly perfect example went from 100% working to suffering from many bad blocks within the span of about 2 weeks. A good collectors item, and not much else.

[@compu85]

Wow they really got more speed out of the stepper compared to the 20mb version! The sound is even better... less of a rocks in a blender :)

[@TheDiskMaster]

Interestingly, the 8425 also had a performance variant that was equivalent to this - The 8425F. Sadly, mine has a bad control board!

[@JankPods0201]

I love the stepper of these late MiniScribe drives! Specifically the 8425 and your 8450!

[@TheDiskMaster]

Thanks, the 8425F and the 8450 shown here share the same sound.

[@80sCompaqPC]

Been looking forward to seeing this one in action! Love the sounds. It really does sound like a baby 3650. It is a crying shame they aren’t more reliable. Probably why you see so few of them today. Oh well, would still love to find one for my collection at some point!

[@TheDiskMaster]

Indeed, this was a lovely addition to the collection. When I first got it, it had 1 bad sector, but it's gotten a lot worse sadly.

[@bobjoe2827]

The alignment of the interrupter is starting to slip on this drive (that problem could be repaired), however it looks like head 2 is failing. You are right about these drives being "junk", many (but not all) of them use plastic for the actuator gear rail. This leads to gear slippage which throws the carriage out of alignment with track 0. The only redeeming quality of the MiniScribe 8000 series is that they are easy to swap platters on and are fairly plentiful. I had to replace the spindle motor on my 8450XT which was a pain, but was at least doable.

[@TheDiskMaster]

How can you tell the interruptor is slipping? Within the span of a few days this drive went from working with 0 bad blocks to mostly bad blocks. It's just junk.

[@bobjoe2827]

@@TheDiskMaster The drive recalibrates twice during spin up and has trouble with the higher cylinders. I have an 8425 that had this same behavior and it turned out to be one gear tooth out of alignment. MiniScribe was known toward the end of their existence to use stepper alignment to produce drives with the least number of bad sectors during final testing (hiding the bad sectors between tracks). This process came back to haunt these drives as the rack and pinion started to wear out and develop slip, which gave MiniScribe's drives a bad reliability record (and rightfully so). You can tell if your drive's alignment can be repaired by opening it and pressing down lightly on the head carriage corner closest to the stepper motor. If while pressed down the interrupter moves freely the drive is doomed to suffer further alignment issues and in my opinion isn't worth repairing.

[@TheDiskMaster]

​@@bobjoe2827It has trouble across the entire cylinder range, and the double initialization is a result of a slightly sticky stepper.