Recent content by demonlg

I don't understand!

Where i buy this board?

Yes I agree with you, but in some cases I did it, I was just wondering if the chip clock was strictly necessary for the CPU to work or could start anyway worth the system time.

Hi at all, i'm trying to restore two logic boards of mac classic, both with very damage caused from battery explosion! One of this board have damage to the CPU pins, i have desoldered CPU cleaned all and resoldered but have to rewire any pins, hard work. The other is ok to the CPU but the...

Hi, tomorrow i send photo of my classic, yesterday i have installed the hdd, i have found a 1gb conner scsi disk from germany, formatted with patched hd tools and then I have installed system 7.1.1. But now i have a problem with stuffit 5.5 tools and decompressing game or other software on this...

All ok after two days. I have replaced the 2n3904 with new one and now system working. ( just for info with a bc547 rotated the screen image have a distortion to right side of screen). I have found a scsi hdd with 136mb of space and seems to working, spin and head check is done. Now I have to...

Ok, i have temporaly replaced the 2n3904 with a bc547 for rapid testing but with 180 degrees rotation for differencies on it pinout, the bc547 have emitter and collector inverted from 2n3904. Now boots up perfectly and screen is ok. I have ordered the original parts, because the bc547 have a...

2n3904 is NPN and not PNP sorry for error.

Ok, on the dead mac scroll manual i have found the same problem and it report to a broken 2n3904 on neckboard, and yes it is faulty, one of its pins going to one of shorted zener diode of last post. I have tested with multimeter and with transistor tester, the first sign value in all sense but...

I'm not give up, sorry for my continuosly posting, but i have to save my work. In precedent post i have wrote a low resistance on shotky diode in output section, tracing this line going in area of wire for crt nek board. I have checked component in this area and on nekboard and i have found two...

I give up! Now computer start correctly, chimes on boot ok and try to boot from floppy, 5v and 12v are ok, but the screen not powering up! The tube is completely off, heater orange light on tube is not present, i don't know if the HV is present or not, and i don't have enough skill to check on...

Baaahhhh! This mac have a demon into it! Now i have returned it on for 30 seconds and it boot correctly with bong sound, voltage 5,10 volt and 12,1 volt... video ok, the shotky diode do not in short but have a low resistence on pins, in both sense of testing...now i try to power up for more time...

Now, replaced again irfbc40, replaced tda 4605, reinsert original output shotky diode on 12v and 5v output rail, reinstalled original rifa caps and original first line filter big black capacitors, controlled all new electrolitics caps and all zener 1n4148. Turned on first time i have a little...

Situation, blowned again irfbc40, blowned tda4605, short on rectifier diode on 5 volt output, for now! All after power up and working this night for any minutes. I have checked all replaced component if i miss polarization but all are correct.I don't know!

I'm very do not say what appened! I have replaced mosfet and now is blowned up the 4605 chip and not the fuse. 'm very angry!