Thread

Can someone tell me what this is?

68kMLA Hardware 9 posts Oct 15, 2012 to Oct 17, 2012

#1 Mon, 15 Oct 2012 - 19:51 68kMLA

This is the power supply board from a 1990 Jasmine 20MB Direct Drive. I plugged it in after 20 years and heard a faint pop and then nothing. No power. Upon taking it apart, I saw this:

It looks as if it's leaking but it doesn't look like a capacitor.

#2 Mon, 15 Oct 2012 - 20:22 68kMLA

If this datasheet is to be believed it is an Opto-Coupler. These components use internal LEDs and Photo-Transistors to act as "no contact" switches to control things without direct contact. This keeps more sensitive 0-5 volt digital logic from being damaged when improperly connected to AC or high voltage/current circuits, and so it makes sense to see one in a PSU. It would be my guess that it either failed as a result of corrosion/fault/shorting on the higher-voltage side, or simple breakdown of the component over time (seems unlikely). That goo may be unrelated.

It may be worth your time to take a look at stuff closer to the drive, are there any wires touching that don't look like they should be? And components a little too close to each other?

A more knowledgable member here may be able to offer wiser advice.

#3 Mon, 15 Oct 2012 - 20:40 68kMLA

what i'd do is gut that board outta there… and install one of those power bricks that come with the USB to SATA/IDE adaptors for 12 bucks.

hardwire it into the plug that is already there,,, and your up and running.

#4 Mon, 15 Oct 2012 - 21:23 68kMLA

Looks very much of a Cutting Edge -brand external SCSI HDD's.

#5 Mon, 15 Oct 2012 - 22:52 68kMLA

It does look like a Cutting Edge drive, doesn't it? I'm gonna look for one on ebay. If I can buy one cheap, I can just swap out the power supply.

This drive is the first hard drive I ever bought and it went with the Mac Plus I bought in the 80's so I want to restore that entire system. I bought it at MacEmporium on 23rd street in NYC for a whopping $599.99 in January of 1990!

If anyone sees a compatible power supply anywhere please let me know so I can buy it.

Thanks,

Randy

#6 Tue, 16 Oct 2012 - 18:00 68kMLA

The goop isn't all in one place, there's a separate blob of it which makes me wonder if it was added at manufacturing time. :?: Hard to tell from a pic

For a power supply I'd suggest Digikey or a similar company. They have hundreds of different power supplies. Might not be any more than a dodgy used one

#7 Tue, 16 Oct 2012 - 19:12 68kMLA

The goop didn't come from the optocoupler. It's hard to tell from the picture, but is one of the capacitors on the left bulging or leaking? Is the goop wet or does it feel dry and rubbery? It looks to me like it might be silicone adhesive applied when the thing was built.

If you heard a faint pop, check to see if the line fuse is blown. It's not uncommon for the chopper transistor to fail shorted, usually when a solder joint gets flaky. If that happens it will blow the fuse. You could replace the power supply easily enough, but they're usually pretty easy to repair.

#8 Tue, 16 Oct 2012 - 19:16 68kMLA

That must have been one of the last drives manufactured by Jasmine. Note that the mechanism is a MiniScribe and looks like it was the original equipment.

From March 1989, Jasmine and Rodime (their disk OEM) were at legal war which contributed to the demise of both companies. My understanding is that Jasmine folded in early 1990 before they shipped the DirectServe (a truly interesting AppleShare server) in significant numbers.

The original DirectDrive (strike DirectServe) drive was not mains powered and drew power from the floppy connector. Does anyone know when Jasmine first shipped conventional SCSI drives?

#9 Wed, 17 Oct 2012 - 01:27 68kMLA

usually when you hear a pop and death, something blew up in the power supply.

Unfortunately, it needs troubleshooting to find out where the fault is, and requires extensive electronics knowledge. If this is a task your not sure if you can handle, i would just throw it away and hack in a new 5/12 power supply in it.