Recent content by d3jsp

Hey Bolle!! I'm happy to send it over, will send you a message

Hmm, weird. I don't see any physical damage on the board at all and the CPU works so it has to be one of the chips

Hmm, it doesn't work on a Centris 610 either, no chime. Maybe the gal or cache chip on the quaddoubler need to be replaced. Do you know if there are any clones for the GAL chip?

Swapped Q1 for a known good bt3904 from a working LC550 board and now it won't boot at all, no chime, just grey screen. ADB_IN, ADB_OUT does have ~4.x V though. I thought these were the same transistors

What should be the voltage on this ADB data line? I can't find any faults between ADB_IN, ADB_OUT and the port and am starting to suspect a faulty Q1 since I am only getting around 0.3 V on the data line. Should it be around 4.2-4.3v? Also reflowed cuda and don't see anything obvious there

This is strange, don't see any obvious broken traces and the set clock modal gets instantly dismissed as soon as the OS boots so I wonder if something is being spammed on the line. The "didnt shutdown properly" modal stays though, always.

Seems like adb goes to pin 20 on the cuda just fine, what else could be broken further down

Got a Macintosh TV with no ADB inputs from either keyboard or mouse. Fuse F3 is fine and known good keyboard is getting 5V. Caps locks work slowly but all other locks just lights up and goes out instantly. Wondering if it's a break from the cuda chip. Does anyone have schematics for the...

did you ever figure out how to fix the grey screen issue?

Attaching some full res pictures

The CPU indeed does boot! running at 25mhz with a co-processor. That means something else on the quaddoubler is defective or just not compatible with the LC?

I can try! would that boot on a 475?

Ahh got it! Unfortunately it still will not chime with the pin and showing up as a Quadra 605 with the original 25 MHZ CPU. I guess maybe the 68040 on the quaddoubler is dead? Can I replace it with another 68040 or LC040 chip?

is that J18? There is nothing on J18 for me and still shows up as an LC 475

It's not overclocked, just a stock LC 475 but won't boot with a quaddoubler. It does say 610-U1 on the gal chip though