Recent content by JDW

@David Cook I really appreciate the time you took to do that TechStep testing and provide a detailed report. Thank you! I’m getting ready for work now, so it all will have to be done after work tonight. Specifically: 1. Remove and scrape all legs of both ROM chips. Test and see what happens...

@Garrett Thank you for your advice. I actually had removed both ROM chips and re-socketed them at the time I recapped and overclocked (via resistor removal) the board even though the board was working fine. I did that restocking just to make sure everything would be OK. Even so I could go...

Last but not least, I tried my TechStep. I tried to enter TestMode but the TechStep responded saying ADB communications failed. Sadly, I had the same issue when I tested my fully working stock CC motherboard, as mentioned in my video here. Sadly, I simply cannot remember if I tried to test the...

I'm not testing the LC520 board inside my CC Mystic again. I removed the RAM and VRAM SIMMs, as well as the socketed FPU. I installed the PRAM battery after that and tested. Same as before. I flip the power switch, hear the CRT circuitry power up, then I press the Power Key on the keyboard...

@David Cook CUDA chip PIN-3 scope measurement (LC520 board with PRAM battery only)... CUDA chip PIN-4 scope measurement (LC520 board with PRAM battery only)... CUDA chip PIN-24 scope measurement (LC520 board with PRAM battery only, IIgs Keyboard Attached)... Keyboard Power Key NOT...

You've done a lot of board repair on your YT channel, so I really appreciate your kindness in making time to offer me feedback. If the CUDA is bad though, finding a replacement chip may prove difficult because it could only be sourced by removal from another logic board, correct?

I appreciate your excellent advice. My 520 board and scope are at the office so I’ll check tomorrow, but for now the CUDA appears to be the 28-pin IC shown top-left in the photo below.

I launched Mini vMac 26 (Mac II edition), booted into my S7.5.5 drive, installed After Dark 3.0b, installed the OJ module, restarted, clicked Demo, but found it still broken. But when I used the hot corner, it FINALLY worked for me! Wow. Lots of time and effort spent on this, but at least I...

I tried both the demo button and the trigger corner. Neither worked for me.

As mentioned in my previous post here, AD4 didn’t work for me in Basilisk II in terms of getting that OJ module to work, although all the stock modules did work fine.

I don’t have the software open in front of me but I’ve used it enough to remember. In one of the menus on the right side, there’s a command that lets you remove any Mac displayed in the results. I always use that menu to remove the bothersome PM6100 results.

Whatever killed my LC520 motherboard didn't harm the Apple-branded 320MB spinning platter drive (Quantum LPS340S, which originally came with the LC575 and was connected at the time I tested the LC520 board). I put that HDD inside a PowerMac 9600 this evening and it booted the machine right away...

I sadly didn’t re-test the LC520 motherboard inside my CC Mystic immediately prior to testing that motherboard in the 575 chassis, but I did test the 520 board many, many times after my recap inside the CC Mystic and it worked perfectly every since time. The last test of it inside the CC was a...

I put my multimeter into continuity check (beeper) mode and put the probes across each polymer tantalum capacitor. No continuous beep, which means they are not shorted. Then on the solder side, I checked the factory solid tantalums. No long beeps on any of those capacitors either. Separately...

When I tested my LC520 motherboard inside the LC575 body, I had my external BlueSCSI v1 attached, but its LEDs never lit up. I tested that BlueSCSI just now with my LC 575 motherboard inside my CC Mystic and the blueSCSI lights normally and it’s drives mount on the Desktop just fine, so it...