Rosen Flea Market IIfx Restoration

[LaPorta]

Hi everyone,

As some of you may be following, I got this IIfx for free at the Adam Rosen house flea market. It was listed as too far gone to sell. I snapped it up in a heartbeat. First, it is in very good condition cosmetically, with a few scratches and dings. Minimal to no rust inside. Incredibly, two Maxell bombs were inside, unexploded. Those were removed and pitched immediately! I took out two NuBus cards that were inside, they look like video cards. A third one I found in another box I will include here. All video cards! Unsure if they are generic or require specific monitors. I'll include photos here.

I just removed the logic board. Appears in very good condition, some leakage from one electrolytic SMD cap at C9 corroding R4. That will get cleaned up and all electrolytic replaced. I'll look into re-capping the PSU as well. Stay tuned!

 

[LaPorta]

As far as RAM: I looked up the Bank B SIMMS. They are 8 MB sticks each, so that's 32 MB in bank B. As for A, there are four sticks of Microtek memory, 9031. Each  stick consists of eight Texas Instruments Modules labeled as such: TMS44100DM-80 HAP 0442 1. I am unable to find any information on how much each is worth.

 

[MJ313]

r3 is where I had startup circuit issues with mine-- I am only pointing it out because your r3 looks a little corroded and I am assuming it's a common issue with these boards because of it's proximity to one of the electrolytic caps.  If it won't startup (via power button or keyboard) but are able to jump it to start it, that may be one of the first places to look at. 

 

[mdeverhart]

Each  stick consists of eight Texas Instruments Modules labeled as such: TMS44100DM-80 HAP 0442 1.

I couldn’t find a data sheet, but what I could find indicates that each IC is a 4 Mb (512 kB) DRAM, making each stick 4MB.

 

[LaPorta]

48 MB total isn’t bad!

 

[LaPorta]

Yes, the startup circuit is dead, I am tracing the areas that are shot. I didn't even try to turn it on: after what I had to do with my Macintosh II, I knew what the deal would be.

 

[Unknown_K]

That second Nubus card (Rasterops) is a nice card.

 

[LaPorta]

Well, very quick success, actually. Desoldered the R4 resistor. Cleaned what was left of the pad, used some adhesive copper foil to repair the trace to the underneath via. Desoldered R4. After that, I replaced C9 and C24 with new organic polymer caps. Replaced everything, and fired her up! Now for cleaning...

 

[trag]

Nice work.   Please continue sharing.  It is fun to follow along.  Thank you.

 

[krishnadraws]

Nice work! Those bits of copper foil blend in - I can't even see where they're at!

 

[LaPorta]

Thanks! It’s soldered

over, the little tail extending to the via.

 

[Fizzbinn]

Very cool, where does one obtain the right type of adhesive copper foil for a repair like that?

 

[LaPorta]

You know, I found it on Amazon somewhere. They actually sell the stuff for kids making jewelry and such, but I find it extremely useful for this application. I got a whole roll of 1/8" wide stuff, and it will probably last forever.

 

[Fizzbinn]

4 Pack Copper Foil Tape,Copper Tape Double-Sided Conductive Adhesive for EMI Shielding,Slug Repellent,Paper Circuits,Electrical Repairs,Grounding(1/8"x21.9yards)

$9.98

https://www.amazon.com/dp/B07R6HNDDX/ref=cm_sw_r_cp_tai_aFfyEbN7S7BXE

Electrical repairs AND slug repellent, what a deal!

 

[LaPorta]

5.25” HD still works! This one and the one in my II seem to be very robust.

 

[LaPorta]

And...nuts. So I had it running (as you see). I did only two things:changed the monitor to millions of colors, and turned on 32-bit addressing. Figured I'd see just how much memory this thing really has. Restarted the machine via software restart. Got the chime...then the chime of death cord. I re-seated the RAM, same deal. Disconnected/connected the HD, same thing. Not sure what exactly I did, or if I did anything...next, I removed the batteries for a few minutes, figured I'd clear the PRAM and 32-bit addressing in case there was bad RAM causing an issue at the startup check. Still occurs.

During one of many restarts, I also got the code that in the Dead Mac Scrolls for a IIsi of all things says that it is an HD issue, but I disconnected the HD and it still happens. The error was 0000000F/00000001. Every other time, I get no video displayed at all.

I found the following in the Sad Mac Error Codes postings:





$000F


Reserved for Macintosh compatibility.

I haven't the faintest idea what that means.

 

[trag]

There are something like three jumpers (it's been years since I looked) near the front middle of the logic board.  I've never been able to figure out what they're for.  Perhaps they're misconfigured?  Unfortunately, I also don't remember what the correct configuration is (all unoccupied?).   But someone with IIfx handy should be able to look.

 

[LaPorta]

Interesting. I was also thinking that perhaps one of the NuBus video cards was not able to operate with some setting I changed, meaning the millions of colors or 32-bit addressing (thought that should have been cleared with PRAM batteries out). I may remove the NuBus cards and just use one at a time to see if there is some sort of conflict.

 

[LaPorta]

Update: I figured it out. The IIfx didn't like the larger RAM in back A while the smaller was in bank B. Swapped them, and it works just fine. I am now discerning what my cards are. One is a Radius TPD II Two-page display card. That does me no good with now two-page display! The really good one is the RasterOps PaintBoard Li. It can even bust out millions of colors! The last is the SuperMac ColorCard/24, which can do 640x480, but also at millions. Strange though, upon each restart, the RasterOps defaults back to B&W...I'll get the original driver software and see if that solves it.

Otherwise, there's a total of 20 MB RAM: 4x4 MB, and 4x1 MB. This is equipped with the factory 500 MB hard drive, so that was pretty cool as well. Many documents on here pointing to this thing being from Michigan, so that must be it's original home.

Anyone know where to find a long floppy cable, and maybe a NuBus ethernet card? I could always make the floppy cable, I suppose.