Recent content by ijnfuso

On the old analog board I changed it, and this other analog board had already a changed one. So I either bought a bad optoisolator, an analog board with a new bad optoisolator or the logic board is laughing at me.. Edit; even with it changed the issue is still the exact same.

Contact me if you are willing to sell a Mac Plus logic board.... EU only

Well it's official, I have completely gone insane. I bought a CRT and nope, still same issue. I have no idea what this damn macintosh has.... I think I'm just going to give up and sell it as spare parts.

Seller on eBay proposed a good deal for a working CRT for the Mac... should I give it a shot..? Or should I try something else?

g'day

Here I am, a bit late (I got sick) but I bring news. I have reflowed every cold/cracked joint on the board and every connector joint, and double checked afterwards... to be honest, there weren't many but I still resoldered the connectors for good measure. Readings without the floppy attached...

Thanks for the tip... I'll do that tomorrow and update the thread after I reflow every bad joint (it's 1:30 am and I'm very tired)

I just checked the continuity, and both of the switches work as intended, nothing when the switch is not pressed. Well last time this thing worked the RAM wasn't a problem... I also tried reseating it and cleaning the connectors both on MB and RAM, and nothing changed. Haven't reflowed it... I...

I already tried lowering the voltage and it did not change anything. I also reseated the rom, the ram, tried putting in a battery, but I got no luck whatsoever.

Welp, the other day I got a new analog board. Recapped the three RIFAs, the seller said it was taken from a working mac, and guess what? It still has the same issue! I really have no idea.... could it be a CRT issue? Maybe the CRT has weird current draws or has issues, I don't know. Really stuck!

I checked online and found at This github page that Q12 can be a "BR103 reversed" (?) Now I don't know if that's possible or how to reverse a transistor, so, not really sure...

Searching online I read that Q12 doesn't have a direct replacement as it has been discontinued, and, can't find anything else... what can I do? Also It's almost like Q10 is glued to the metal bracket, how would I remove it?

Well, I was checking voltages between C35 and C39, I am getting around 300/301DC.... while I was doing that I heard a bang, and, it was Q12 that said goodbye (it exploded, popping the fuse too). And also seemed to burn R53 too....

Unfortunately, I have already tested every cable… the analog board is not even getting 12v or 5v to the power rail, and no high voltage as well…

Right- I am getting around 230V after the thermistor with switch on.... what else could I test