Powerbook 165c Floppy Drive Problem

[T-Squared]

I would say that I'm a vintage computer collector now, since I've added a new computer to my collection of Apple II, Mac 128k, Zenith Supersport, and NEC Versa computers.

Since I can't transfer info from Mac-128k-formatted (400k) disks directly to a modern computer, I figured that an intermediary computer is needed.

I picked up a sweet Macintosh PowerBook 165c from eBay for only $35!

The only problem is, I don't have a proper power supply for it. I had to hack together an existing power supply that would provide proper current.

It seems to work. The computer starts up, the hard drive responds nicely, and the screen works perfectly.

Now, here's where things get frustrating. Inserting a disk into the drive, or even booting up with a disk causes the computer to reset and attempt to boot again. Is this because the power supply isn't providing enough current? (I did disconnect the SCSI drive inside, and left the floppy drive as the one solely connected.)

Unfortunately, really cheap-selling Original Apple adapters are hard to come by, and almost all of the adapters that I can find say the (almost) exact same power specifications that I need.

The power supply that I hacked together is a 7.5v 2100mA (2.1A) supply (Excess of Volts is dangerous, Excess of Amps are not, so I know I'm not overloading the computer.), and the original OEM adapter is a 7.5v, 2.0A supply. If the supply is properly working, why am I have so much trouble? (Granted, I did plug a 9v, 1A plug before then to test, but it didn't seem to cause any lasting damage, because I immediately unplugged it.)

 

[raoulduke]

Are you sure the OEM adapter says 2.0A? I'm having a lot of trouble actually tracking down specs on the adapter. The manual says 922-0376, but includes an asterisk saying to refer to a parts list I suspect is no longer available. There's this: https://www.ifixit.com/Answers/View/170059/AC+adapter+for+PowerBook+165c ; http://duracelldirect.hu/laptop-notebook/apple/oem-pno/922-0376.html ; but I've also found different specs (including 8v and 2.0A).

The symptoms you've described could be consistent with a current issue. But I'll defer to anyone with more knowledge.

 

[krebizfan]

Well, a lot of power adapters were very optimistic about their ratings. Since most SCSI hard drives use more power than a floppy, if it works with the hard drive it should have enough power for just the floppy if the SCSI drive is unpowered.

I would suggest checking for any sort of short around the floppy drive.

 

[T-Squared]

Are you sure the OEM adapter says 2.0A? I'm having a lot of trouble actually tracking down specs on the adapter.

Actually, it's easy to find. Many people have taken pictures of the adapter on eBay, and some are high-enough in quality that you can read the specifications on the back.

 

[raoulduke]

I was going to offer a post explaining that M5652 and M5651 (and that's just for instance) look nearly-identical - and that while M5651 is 2.0A, M5652 is 3.0A. But you've got this clearly. Good luck.

[the manual - in reference to the 180 - cites M5652 - meaning you *likely* (since the manual also notes the adapters are 'parts-specific') need 3.0A. Guess it wasn't so easy to find...]