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About JNizzle

  • Birthday 01/04/1997

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    Engineering, retro electronics and video games!
  1. I have a Mac Plus that has been working perfectly for decades, but it has recently developed a few issues. When the Mac boots, it will promptly reach the desktop as usual, but anywhere from 1-5 minutes after booting, the Mac will crash out entirely to a blank screen and replay the startup bong repetitively in no particular pattern until I shut the Mac down using the switch at the back. When the Mac crashes, it will play the startup bong repetitively about 5-10 times and then it will somewhat restore itself and begin loading, only to crash out again during the startup process either before
  2. Awesome! This may come in very handy with my Classic, which I've hit a bit of a wall with. Thanks!
  3. We're talking about C33 and 36. I'll take a photo of what I replaced, and what I replaced these caps with. I'll post the links to imgur, as all my pictures are coming out huge for some reason. Caps I replaced: https://i.imgur.com/VOwJRCY.jpg What I replaced them with: https://i.imgur.com/PaH0Iga.jpg I tested all the diodes in the rectifier, I'm getting about 2.1mV in one direction and about 4.6mV in the other.
  4. I was poking around in the power supply with my multimeter, and those two caps that I replaced have contact with ground. I'm at least 90% sure that's where my problem lies, as I was at least getting a PICTURE before I replaced them. What actual purpose do they serve? Also I've yet to find any continuity between any component and the live and neutral prongs of the AC input.
  5. Alright people, I'm still having issues with the mac. I replaced the two film capacitors with two caps of the same rating and voltage, the dude at Radio Parts (aussie electro store) said they should do the trick. I soldered them in and replaced the fuse with an identical one. However, I didn't even get to turn the mac on before it tripped my house. I plugged the cable into the wall, plugged the other end in my mac, switched it on at the power point, and everything went dark! I think I may have a short somewhere, but I'm unsure.
  6. Alright, thanks for the help everyone. I bought some more caps to replace the two film ones on the AB, they're not identical, but they're electrically the same. I bought some fuses as well. When I get home I'll fix it all up, and I'll try re-seating the cables to the logic board. I'll also try re-seating the RAM.
  7. Yeah I think I've chosen caps that are a little too high for what was originally on the AB, but I'll swap them out later. I swapped the purple 100uF 200v capacitors out for 100uF 400v ones. Also, you mentioned that the caps might have trouble staying "formed". What exactly does this mean? I tried googling it but I'm not getting clear stuff or I'm just getting walls of text.
  8. Okay, noted. I will replace those caps as I just checked, and they do look a little old and cracked. Also, I was under the impression that any capacitor could be replaced by one with the same capacitance, but any HIGHER voltage, as the voltage on a capacitor is only it's minimum voltage. Correct me if I'm wrong.
  9. Okay, now some deep dark stuff is going on. I plugged it in, and it's fuse blew in half. It tripped the whole house, everything went dark. I can't do any more testing until I find a new fuse, but this has me thinking, is there just some potentiometer I just need to adjust?
  10. Alright, so I resoldered all the contacts around the flyback transformer, and I resoldered the area around that burned-out CRT power plug that I mentioned, because it was covered in a dusty black residue. I'm not sure if this fixed my problem though. I seem to be getting a more solid distribution of horizontal white lines, but my computer hasn't booted since I resoldered. Any ideas? I also haven't heard that whistling in a while, so that may have fixed itself.
  11. As I've been turning this Mac off and on throughout the day to test how my repairs have been holding up, I've noticed another weird thing. There is no startup bong and the screen does this stripy half-on kinda thing, where the top of the screen just isn't working and the other half is showing horizontal stripes. Tapping on the side of the Mac restores the picture and I hear the healthy startup bong. I've opened the Mac up again to see if anything is screwing up. This is an odd case!
  12. Hello people! I recently acquired a Mac Plus while doing a clean out of my grandfather's old factory. The keyboard and mouse were FUBAR, as they had been left under an old can of paint which leaked all over them. He said that there was also a hard drive somewhere, but we couldn't find it. I scrubbed as much old paint of this Mac as I could, and besides from a rather even coat of yellowing, it seems to be in pretty good nick. I took it home and plugged it in, and it made the start up bong and the floppy drive made noises, but the screen never fired up. I cracked open the case and be
  13. Thank you so much for your help, I'll definitely try this when my exams are over! I met someone who will lend me a Mac Classic in perfect working order, so I'll be able to test most of my components in there and hopefully rule out some issues.
  14. I tested the voltages, I discovered I'm getting about 4.4v and 11.4v. I adjusted the potentiometer, and I can nail 12v, but I can't get 5v. It just seems to top out at 4.6v and I can't get it any higher. Thoughts?
  15. Hey guys! Recently I managed to pick up a Macintosh Classic in very good nick, however, it wasn't working. The previous owner told be that he was using it one day, and the Mac made a bang and stopped working. He said that the fuse had gone, and that I would simply have to plug in a new fuse. I took it home and tried to power it up again just to see if I was lucky, but sure enough, it was broken. I didn't hear a hard drive spin, no beep, no CRT noises, nothing. I cracked it open and sure enough, the fuse was missing. I bought an equivalent fuse and plugged it in, I powered it up, but st
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