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Floppies_only
June 18th, 2008, 12:14 AM
Gang,

I need a new motherboard for a Macintosh SE with a 1.44 Megabyte floppy disk drive. Does anybody know how to tell which motherboards are compatible with this superdrive?

If I can get the right one, I intend to freecycle this Mac to somebody who wants an older Mac.

Thanks,
Sean

Unknown_K
June 18th, 2008, 02:53 AM
The only differences between an older SE and a SE FDHD are the ROM chips and the floppy controller chip. If you have a dead SE FDHD motherboard you can just swap out those chips with any SE to make a SE FDHD (superdrive).

Most motherboards die because of bad capacitors, so you can probably revive it but recapping what you have.

Floppies_only
June 18th, 2008, 04:42 PM
Most motherboards die because of bad capacitors, so you can probably revive it but recapping what you have.

Actually, the problem I am having is even easier to solve. I would just need to resolder the connections for one of the ADB connectors. But I don't have an anti-static mat to do it on.

Thanks for the help.

Sean

Druid6900
June 18th, 2008, 08:39 PM
Anti-static mats are very useful.

They make a lot of money for people that sell anti-static mats.

At this time of the year, static isn't much of a problem unless you plan to attempt it while shuffling your feet across a wool rug while petting a long-haired cat.

Floppies_only
June 18th, 2008, 09:59 PM
Anti-static mats are very useful.

They make a lot of money for people that sell anti-static mats.

At this time of the year, static isn't much of a problem unless you plan to attempt it while shuffling your feet across a wool rug while petting a long-haired cat.

I became aware of the problem while watching some of Apple's internal videos. Some guy on eBay was selling these on DVD. When I watched the one on anti-static measures it said that just the rubbing of your clothes on your skin during normal movement was enough to damage semi-conductors. The narrator took a simple semi-conductor (IIRC it was a zenier diode) and measured it's output on a big digital voltmeter. Then he handled it while moving and measured again. The voltage was less the second time because it had been damaged. They had a fictional scene where a woman who was staffing a computer store was asked to sell a card to a customer. They showed her unwrapping the card to check to see if it was the right one. They said that that was enough to fataly wound the electronics on the card, and that the damage often wouldn't show up for a few weeks after the precipitating event.

So now that I've seen that video I try to take measures to prevent ESD, because they just don't make vintage computers any more, and killing one of them when it could be put to use harms the environment. Apple made a believer out of me. I just wish less than ninety percent of eBayers would observe the same precautions. My EGA cards came in anti-static bags, but most hardware comes wrapped in bubble wrap. I just hope that I've got lucky with most of it.

Sean

Unknown_K
June 18th, 2008, 10:19 PM
You are going to replace a whole circuitboard because you don't have an ati-static mat available? Solder it on without the mat and if it doesn't work then get a new board, not like it will hurt anything.

Floppies_only
June 18th, 2008, 11:54 PM
You are going to replace a whole circuitboard because you don't have an ati-static mat available? Solder it on without the mat and if it doesn't work then get a new board, not like it will hurt anything.

I am getting to the point where I have almost all of the vintage computer stuff that I want^H^H^H^Hneed. So I anticipate that my cashflow situation is going to improve at some point in the future and I will be able to buy an anti-static mat. So I will hang on to the motherboard that needs resoldering (if that's what it needs) and perhaps in the future I will try my hand at fixing it. I have an ohm meter, too, so I might actually be able to tell if I did it wrong.

I was thinking that the iron might be able to transmit quite a spark to the circuit, depending on how good the insulation of the handle is.

Sean

Druid6900
June 19th, 2008, 01:59 PM
I have a wrist strap grounding thing that came in one of the boxes I got yesterday. You want it?

In almost 40 years of fixing computers without mats or grounding straps or SFA, I have never lost a chip to ESD. That includes walking around with a whole hand full of CMOS chips.

In fact, I don't even KNOW anyone that's ever blew up a chip due to static (and can prove it).

Take the strap. If it will make you feel better to be grounded, then more power to you.

squirrel-steam
June 20th, 2008, 10:16 AM
I completely built my (fully functional) gaming computer with out static mats, and only used the static wrist band a couple of times. It have 5 of those, 1 came with my brothers stuff he bought for his gaming computer, 1 came with my case, 1 with my heatsink, 1 with my power supply, 1 with my video card. I've carried most of the parts in my hand(s) without any sort of static protection, and im on the computer using those parts now!

Floppies_only
June 21st, 2008, 12:11 AM
I completely built my (fully functional) gaming computer with out static mats, and only used the static wrist band a couple of times.

I realize that it's possible to handle digital electronics without damaging them even though you aren't wearing a wrist strap. The Guides To Operation for the original IBM PCs just say to handle options (ISA cards) by their edges. My point is that they aren't making vintage computer equipment anymore and taking precautions is not that difficult, so why not do it to make sure that you don't get unlucky.

That's what I intend to do.

Sean