Recent content by ymk

Right. SCSI 1/2 are collections of standards and no device implements all of them. Trying to improve the I/O performance of a 16MHz SE/30 is probably a lost cause. JDW benchmarked SE/30 disk performance, showing significant gains with 030 and 040 accelerators. Timing the duplication of a...

I'd still go with a conformal coating or lacquer over hot glue. It will penetrate better, trap less heat and won't soften when warm. I don't see a reason why it wouldn't be permanent.

If you can identify the whining coil, conformal coating may silence it.

Remove the thing that's different.

Make sure the heat pipe hasn't failed.

Neat game. What did you write it in?

Sounds like they might be 1.27mm or 0.05" pitch.

Very nice! I've been using THINK C 5 on a Centris 610. The 1152x870 display is easy to work with and compile times are reasonable. I test on monochrome Macs via LocalTalk, but I wouldn't want to develop on them. Here's something from 1995:

I think a Classic PCB is in development. I don't blame you for setting it aside. I've got several logic board puzzles in storage, but too many better things to work on.

Wild guess, one of the higher address lines? Eliminating the SCSI chip as a potential cause is still progress.

Maybe the data lines? I'd swap the chip at this point. Mouser has the Z53C8003VSG. I don't know if it's compatible.

I checked my board and SCSI controller pin 18 doesn't run to 68000 pin 8. It does run to pin 54 of the BBU. I mixed up the /LDS and /LDS' labels:

Those are low, but I doubt they're causing a problem. Here are the lines on the SCSI controller that reach other ICs. The ones in cyan go to the CPU. I couldn't find any other reference to /IRQ in the schematic. I did trace it to pin 14 of UI6 (which I also couldn't find in there) on a spare...

I'll check the schematics later. What do your +5V and +12V rails measure with that hard drive attached?

Those voltages look OK and show the bus is idle. Check the pins of the controller for electrolyte and corrosion. The nearby rail caps often leak on to it. Swapping or reflowing the SCSI controller is what I'd try next.