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This is a request for pointers to existing topics that may discuss techniques for repairing unreliable 68K-Mac-era 50-pin SCSI HDDs. It's a new direction for me, but (very) recently I've had several Quantum, IBM, Conner, and other HDDs suddenly become unusable. I'd love to return these to...

Not sure I have earned the rank of 'pro', but perhaps you were speaking of the larger audience here :) As I prep all these systems for VCFW, I am seeing a common challenge: HDDs which all through the restoration process were not part of the problem are now failing at the last moment. "NOT...

I narrowed the final IIcx issues to the internal SCSI drive. Guided by memory dumped with TestManager and a listing of the IIcx ROM generated with a m68k-capable objdump (cross-referenced with an annotated listing of a Mac 68000 ROM found online), I found the system was very reproducibly taking...

My IIcx with the 00000003000F*R lockup may have things in common with the topic linked below, and I am following it. I've been meaning to unwind the stack for a while, but have no IIcx ROM disassembly and have been pressed for time. I need to get this IIcx ready for consignment at VCF West and...

Still some infrequent and minor twitching on my SE's video, so I took the final step* and recapped its ASTEC power supply. There was one small area that looked like cap ooze had been there. Now, the suspense begins.. either the video is now spot on, or after a long while it'll do it again. (*...

I had an LC II recently that did not seem to be accessing its ROMs. I studied the 68030 bus protocol and was able to identify a single line between the `030 and the bus ( /AS ) that was open, a broken trace right at the CPU. Repairing that solved everything. I am far from an expert on this, and...

I checked the Apple schematic for the SE. You mentioned that some RAM SIMM socket pins showed no continuity. Of the ones you mention, all are no-connection except pin 5. Are you sure you had contact with that pin? Pin 5 should be signal RA1F (A1 for each SIMM) and be continuous to pin 9 of...

Does the repeating Sad Mac graphic reveal anything about the RAM addressing? I'll power up my SE today and see what I can offer in terms of internal RAM testing advice.

tl;dr: what is Test Manager major error code 000F ? Both IIcx's were stable, and the one with the ROM issues around cap C4 was fun with its million-color RasterOps card. But it regressed last night. It boots, happy chimes, the RasterOps card does its animated splash screen - then the system...

Scratch my reply about the "Winbond FPGA". Not enough sleep for a while. Confused the DP83902 with the AT&T FPGA on the Nubus NIC. Posted without coffee. Mindlessness ensued.

The IIcx with the replacement LL ROM was fine until I fumbled while removing the 12" video card, and the front corner of the card struck somewhere in the ROM and developer button zone as the Nubus connector lifted free. Then, no chime. The system would still boot fine with a ROM SIMM. (Whew) I...

@Melkhior - @zigzagjoe concurs that the two should be interchangeable, and I agree with him that I should hold off on replacing the 640s until there's a smoking gun there.. but I will check Mouser stock today and possibly get a few, just in case, especially if I have an order of other things (I...

Circling back here.. I don't know where my head was at when I decided to drop a "pin compatible" FPGA in for the original without changing the configuration ROM in lockstep. I have a software engineer's POV of an FPGA but, it seems slightly unlikely that the bitfile for any NatSemi FPGA will...

For a few days there, every Mac I own was up and running perfectly. Well, the Q605 still has some very faint digital noise ingress on audio, OK since that was a board with a lot of bad traces. But today the IIcx that had one corrupted ROM stopped chiming. Still boots with a ROM SIMM. Debugging..

I'm not versed in MIDI, and have no MIDI serial interface dongles or MIDI instruments, sorry. I also lack any LocalTalk gadgets.. so I will only test simple serial mode, RS-232. (I did consider getting a LocalTalk bridge early this week, but I'm trying to free up space in my workshop, not the...

Declaring success on this LC II. It survived overnight all reassembled in its chassis, compressing its internal drive to an image file on an external drive. Some level of confidence. Check-boxes left to fill: Do the loopback modem<->printer serial tests. Lots of serial logic at the edge of the...

Found another broken trace yesterday. C13, electrolytic reserve cap for the Egret's battery supply, had a dead-end trace on its anode. Corrosion under the solder mask had eaten through the trace just before a via. I repaired that with no expectation that it would let the system boot .. ...

Some progress today. I'm out of time and will continue tomorrow. /AS, 68030 address strobe, had a bad trace from the 68030 to the nearby via, near C13. This trace looked fine to the eye, but the eye of the via was dark dark corrosion-green. The solder mask over the trace was shiny and smooth...

Just standard small wire nippers, the kind used to trim leads flush with the board, or cut the leads from chips I never intend to reuse, to ease their removal.

I have finally cleared the decks enough to get back to a brain-dead LC II that came my way. It has never booted. Back when, I did some quick poking around, saw some signs of capacitor death, then recapped the PSU and the logic board and cleaned it up. Still: after power on, all voltages are...