Arths

Absolutely, but that did not change anything

I’ve changed chip F18 and I now have solid horizontal white bars. Another thing is that I seem to loose composite signal every 2 seconds, maybe a clock issue ?

Hi guys, Just received the chips, tried piggybacking but that doesn’t seem to change anything. Maybe there are specific chips I shall try this method on ? If you have any idea, please let me know Thanks Edit : Piggybacking F18 makes horizontal white bars but that's it Arths

Mine uses TMS4164, must be an early revision of the IIc. According to this site, they should be compatible anyway. Ordered five chips from AliExpress, they should arrive in 2 to 3 weeks. Thanks for your advice

Might be a possibility, RAM chip are MT4264 right ? I've read online that I can also use 4164 chips.

Hey guys, Turns out it was the LM311N chip which was causing the blinking power light. Soldered a new one and blinking is gone but it still doesn't want to boot. Hooked the IIc using the composite output and here is what I get.. Sometimes I get scrolling characters instead like so Holding CONTROL-RESET makes the scrolling stop so I guess the CPU at least understands the keypresses. Any idea ? Thanks, Arths

Ok, RalfK from Apple Fritter asked me to test FFF and all I get is zero

Here are my results Capacitors C57 shows zero C44 and C43 shows infinite when speaker is unplugged, .845 when it is Rails Thanks a lot

Thanks for your reply, I will try that as soon as I get home Already measured the 7905 chip and I’m getting voltage in expected ranges, is it a good sign ?

Sorry for the late response Yes I’ve tested without a disk drive and it still won’t boot. What should I check first ? Is there a place on the board where I can check that the voltages are the ones I shall receive ? Thanks for your patience

Just tested the ADB ports while the computer is turned on, I get +5V for both. The Dead Mac Scrolls indicates that it might be the Tokin filter, tested it as well, pins (1-8, 2-7..) show 0V which should be correct ? I really don't understand why is the ADB not working. Plugging a keyboard makes its lights turn on but that's it. Any help ?

Hey guys, Quite a time wrap from 2012 isn’t it ? I got my Macintosh SE FDHD back from storage. I really think that the screen glitches and Sad Macs I have from time to time might be caused by the Power Supply. As of now, I am getting the right voltages from the floppy disk port (+5V and +12V) but the machine is running great so far. I’ll re-measure when it will start acting weird again. I’ve tried to clean the rusty parts with vinegar and it seems the logic board is not as badly damaged as I thought. ADB ports are still not working and that’s the mai

I’ve replaced this one too..

Well, I’ve replaced the internal power supply as well.. same problem. I guess the computer is dead

Nevermind, installed a Netboot server on my G4 MDD and currently installing Tiger through Ethernet Sorry for the double post.