68kMLA Classic Interface

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Jasmine 20MB DirectDrive
Posted by: reallyrandy on 2012-06-20 09:39:33
I have one that has not been plugged in since 1992. I plugged it into my Mac Plus the other day and when I hit the power switch I heard a faint pop from inside the case. Now I get no power. I checked the screw-in fuse on the back panel and I looked at the fuse that's soldered into the board. Both look good.

Any ideas? Is anybody here an electronics guy (or girl)?

I'm looking to either fix this one or buy another one.

Posted by: CelGen on 2012-06-20 15:05:51
Switching transistor or a diode probably blew up on the power supply.

Posted by: reallyrandy on 2012-10-14 11:04:49
I took it apart to see if I could smell anything burnt and everything smells fine. I did see what I think may be a leaky cap though. I don't know much about circuit boards so I took some shots. Maybe one of you guys can ID the problem from the attached photo links.

I looked on ebay to see if I could find a Jasmine 20MB to no avail. Maybe I could buy an old drive with the same form factor and swap out the power supply. Any advice?

https://www.dropbox.com/s/kav5p4uxr763th9/IMG_20121014_134044.jpg

https://www.dropbox.com/s/db61csboydy7l8h/IMG_20121014_134758.jpg

https://www.dropbox.com/s/n4vii975t7klr3l/IMG_20121014_134812.jpg

Posted by: James1095 on 2012-10-16 15:45:12
If you can't get it going, I repair power supplies when time permits. Rates negotiable or will consider interesting trades. Shipping stuff back and forth can get spendy these days though.

Posted by: reallyrandy on 2012-10-22 17:57:47
James, you have a PM.

Posted by: Trash80toHP_Mini on 2012-10-23 07:25:30
I'd test the Drive using another power supply first.

There's no point fixing the power supply for a sticktion afflicted HDD unless you've got another drive to use as a replacement.

I've got "watch this items" for long thin ATX PSUs if you're interested in going the "new" route.

Posted by: krye on 2012-10-23 08:54:49
That pops sounds like a cap. Although caps don't just pop without reason. Too much voltage and you'll pop it. Which means something most likely went causing the cap to be overcharged.

Posted by: James1095 on 2012-10-23 14:28:53
Pops can be lots of things. Caps rarely pop unless they are installed backwards, but when that happens there will usually be cardboard confetti all over the place. More often the pop is either a semiconductor cratering or the line fuse blowing, frequently a shorted chopper transistor. When it comes to switchmode PSUs, the root cause is frequently cracked solder joints or worn out electrolytic capacitors.

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