IIfx Won't boot

[Osgeld]

whatever the answer is don't toss the original, its issue could just be a leaky cap or burned out regulator, which can be pretty easily repaired by someone trained and safe while working on power supplies

 

[aftermac]

They should use the same power supply. The II to IIfx upgrade was a motherboard replacement.

 

[Tempest]

So what's the fix to something like this? Complete replacement of the power supply?

Tempest

 

[Dennis Nedry]

So what's the fix to something like this? Complete replacement of the power supply?
Tempest

That would certainly work. There are people on this board including myself who would like to try to fix it, but depending on who you send it to and what's wrong, it may not get fixed, or it may take more time than expected to figure out what's wrong. If I were you, I would ask in the trading post to find someone to fix it, and get general quotes on shipping, fixing it, etc.

Another option would be to get a working power supply and then sell your bad one to one of us. This could also be facilitated in the trading post. I'd say that's a better option, possibly less expensive too. No risk of expensive labor or needing strange parts. You know you'll have a good power supply. You pay shipping only one way. etc.

 

[aftermac]

So what's the fix to something like this? Complete replacement of the power supply?
Tempest

That would certainly work. There are people on this board including myself who would like to try to fix it, but depending on who you send it to and what's wrong, it may not get fixed, or it may take more time than expected to figure out what's wrong. If I were you, I would ask in the trading post to find someone to fix it, and get general quotes on shipping, fixing it, etc.

Another option would be to get a working power supply and then sell your bad one to one of us. This could also be facilitated in the trading post. I'd say that's a better option, possibly less expensive too. No risk of expensive labor or needing strange parts. You know you'll have a good power supply. You pay shipping only one way. etc.

I would agree with that. The cost of finding another powersupply or Mac II, is probably less than having someone fix it. Does the guy you got the IIfx from still have any Mac II's?

Then there is the benefit of selling your non-working PS... even if it's for the cost of shipping... it keeps a potential replacement part from being trashed. We all know ho scarce parts are getting these days.

 

[Dennis Nedry]

Here's an option, although it is fairly expensive. But if time and hassle isn't worth it to you to find a cheaper one, follow these links. These two run ~$60 range.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230436670409

http://www.welovemacs.com/6610522.html

 

[Tempest]

Does the guy you got the IIfx from still have any Mac II's?

Yeah he had two Mac II's and another IIfx. Are we sure the Mac II power supply is compatible with the IIfx? I thought the IIfx one was different (a variable speed fan or something).

Tempest

 

[aftermac]

Does the guy you got the IIfx from still have any Mac II's?

Yeah he had two Mac II's and another IIfx. Are we sure the Mac II power supply is compatible with the IIfx? I thought the IIfx one was different (a variable speed fan or something).

Tempest

Yup, it's compatible... it just won't have the variable speed fan (ie. single speed). Apple's upgrade path from a Mac II to a IIfx was a motherboard replacement and did NOT include a power supply. All of the voltage outputs are the same.

 

[Tempest]

I got a working power supply from a dead IIfx and it is giving the proper voltages. Unfortunately I'm still not getting any disk or HD activity. However I took a closer look at the board I think I may have discovered the problem. The trace on the top of the board on the left side that goes from the capacitor(?) at C45 to the spot below the second Nubus slot labeled FD15 (between zones N2 and K2) is completely burned out. It looks like it took a hit or something in the past. I'm not sure what this trace connects, but I'm guessing it's needed since it seems to come from the power supply.

I think at this point I'm SOL unless there's an easy way to repair such a thing. As a consolation though I got two nice looking Mac II's from the guy (for parts in case this power supply was also bad), another video card, and another full set of IIfx memory. So I guess even if this IIfx is dead I can at least make my money back selling the memory. A Mac II isn't too bad for a gaming machine I suppose. At least not for the stuff I want to play.

Tempest

 

[Dog Cow]

The Mac II had a variable speed fan.

 

[aftermac]

I got a working power supply from a dead IIfx and it is giving the proper voltages. Unfortunately I'm still not getting any disk or HD activity. However I took a closer look at the board I think I may have discovered the problem. The trace on the top of the board on the left side that goes from the capacitor(?) at C45 to the spot below the second Nubus slot labeled FD15 (between zones N2 and K2) is completely burned out. It looks like it took a hit or something in the past. I'm not sure what this trace connects, but I'm guessing it's needed since it seems to come from the power supply.
I think at this point I'm SOL unless there's an easy way to repair such a thing. As a consolation though I got two nice looking Mac II's from the guy (for parts in case this power supply was also bad), another video card, and another full set of IIfx memory. So I guess even if this IIfx is dead I can at least make my money back selling the memory. A Mac II isn't too bad for a gaming machine I suppose. At least not for the stuff I want to play.

Tempest

That sucks...

The Mac II had a variable speed fan.

The Mac II and IIx power supply a single speed fan. The IIfx has a variable speed.

 

[Dog Cow]

The Mac II had a variable speed fan.

The Mac II and IIx power supply a single speed fan. The IIfx has a variable speed.

That's contrary to Usenet posts which I have read regarding the subject.

Re: Mac II fan noise - an unauthorized solution - 17 Jul 1988 6:17 pm

 

[aftermac]

The Mac II had a variable speed fan.

The Mac II and IIx power supply a single speed fan. The IIfx has a variable speed.

That's contrary to Usenet posts which I have read regarding the subject.

Re: Mac II fan noise - an unauthorized solution - 17 Jul 1988 6:17 pm

Interesting... I'll have to look up a Mac II manual to check that. However, even the person that posted that says he's never heard it speed up or slow down.

Here's the info at Low End Mac for what it's worth:

http://lowendmac.com/ii/macintosh-iifx.html

Although appearing identical to the Mac II and IIx, the IIfx power supply has a variable speed fan to better control noise and cooling.

In the Apple service manual the II and IIx have a different part # than the IIfx... Power Supply 661-0375 (II, IIx) 661-0542 (IIfx).

 

[Dennis Nedry]

The trace on the top of the board on the left side that goes from the capacitor(?) at C45 to the spot below the second Nubus slot labeled FD15 (between zones N2 and K2) is completely burned out. It looks like it took a hit or something in the past. I'm not sure what this trace connects, but I'm guessing it's needed since it seems to come from the power supply.

I believe there may be a short circuit somewhere. It caused the trace to burn and also burned the power supply. So the next step is to test nearby capacitors to see if they are short circuited. Once you successfully find and remove the short circuit...

The easiest and fastest solution is to run a wire directly from the yellow wire on the power supply to the yellow wire of the hard drive power connector. This would effectively bridge the gap, wherever it may be (probably this burned trace), and cause the floppy to come to life as well.

For a permanent solution, you should try to repair the trace that is burned. You will need a soldering iron and a piece of wire. Follow the trace from the burned area until you reach a spot you can solder to. Then follow the trace in the opposite direction until you find another spot you can solder to. Then solder a wire connecting these two spots.

I highly recommend using a 30 gauge solid wire for this. If you strip the wire and it's lots of little strands, it will be more difficult to solder accurately. Solid copper 30 gauge wire can be purchased at RadioShack.

DO NOT bridge this gap or run any wires until you find the short though!

 

[aftermac]

The easiest and fastest solution is to run a wire directly from the yellow wire on the power supply to the yellow wire of the hard drive power connector. This would effectively bridge the gap, wherever it may be (probably this burned trace), and cause the floppy to come to life as well.

That's actually not a bad idea... and probably the safest way to troubleshoot the problem if you choose to do so.

 

[Tempest]

How would I figure out where a possible short is?

Running a wire directly to the disk might solve the problem, but that's still a hack and not a fix (remember the HD wasn't spinning up either). Once I'm sure there's no short I might just try bridging the short with a wire and see what happens.

Tempest

 

[Dennis Nedry]

How would I figure out where a possible short is?
Running a wire directly to the disk might solve the problem, but that's still a hack and not a fix (remember the HD wasn't spinning up either). Once I'm sure there's no short I might just try bridging the short with a wire and see what happens.

Tempest

You can use a continuity tester. Most multimeters have this function, sometimes it's called a diode tester or uses any variety of weird symbols. It's usually the function that looks different. Touch the probes together and the readout should change.

To find a short, first test any electrolytic capacitors. Touch a probe to each wire coming out of the capacitor and see if the tester shows a short. Especially test capacitors near the burned trace. If you find it, replace the capacitor, then patch the burned trace. It sometimes sounds easier than it is, and it's not necessarily a cap, but you might get lucky and find it right away. We can certainly arrange to send it to me for fixing as well. I live in Minnesota so we're not that far away.

 

[Dennis Nedry]

Tempest and I have worked a deal for me to repair his IIfx logic board. I will chronicle the repair here when I receive it in the mail.

"Dennis Nedry" / Ben

 

[Dennis Nedry]

I received the board and other goodies. Here is what happened since then:

A. Checked for a short from +12 to GND or any other rail. I found some suspiciously low resistances. (i.e. a short = 0 resistance.)

B. Removed all RAM and ROM SIMMs.

C. Removed all electrolytic caps from the logic board, except for C42 which I can't readily replace, 1,000uF 10V. This cap has not leaked and does not test as shorted.

D. Thoroughly cleaned the board and blew it out to remove most of the water, then let it dry on a fan.

E. Replaced all the caps I removed with brand new ones. 5 electrolytics and 2 tantalums were used. 1 axial cap was replaced with a radial unfortunately, but it turned out very well.

F. Patched the burned trace.

G. Checked for short circuits again, found none. That's a very good sign.

H. Verified a hard drive would spin when attached to the internal power connector. This is a faulty hard drive however, so no booting took place.

I. Booted the Mac from a floppy successfully.

J. Booted from an external hard drive all the way into A/UX 3.0.1. Flawless and may I say VERY FAST.

K. Checked RAM, there is 8MB of RAM installed. These are 1MB SIMMs. Hang on to your other IIfx RAM, Tempest!

L. Done. I will be sending it back to you soon, Tempest.

 

[Osgeld]

I have some 1,000uf 25 volt caps here, they were removed from a board, but that board was brand new and never used