Jump to content

Jimmy422

6502
  • Content Count

    12
  • Joined

  • Last visited

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. Interesting. The "Mac Classic & SE Repair and Upgrade Secrets" book has the controls labelled differently... I was adjusting the "contrast" pot in your image. I'll have to try the "brightness" one in yours.
  2. It's way too bright. I can adjust the cutoff potentiometer to make it dimmer, but I figured that the brightness preferences should be saving so the cutoff can stay properly adjusted.
  3. I got my Mac Classic up and running after a recap, and for some reason I can't get the brightness preference to save after a reboot or shutdown. However, other preferences like mouse speed, volume/sounds, and the date/time do persist after a restart or shutdown. I've tried a PRAM reset with no luck. Also tried upgrading the system from 6.0.8 to 7.0.1 and neither are able to save the brightness settings. Anyone have any ideas?
  4. I forgot to mention that I reflowed both the pins on the analog board as well as the logic board for those connectors, and sprayed deoxit in both ends as well. No dice
  5. I’m at a bit of a loss here. I picked up a Macintosh Classic that had the usual capacitor leakage. A couple of traces were eaten away, but were easily fixed with some bodge wire. Right after cleaning the analog and logic boards and recapping both, the Mac chimed, booted right up, and worked completely fine. About 2 minutes into playing with it it threw a system error and hard locked up. I waited about 10 minutes and tried again, and it booted right up yet again. Spent probably 15 minutes using it and had no issues, and then safely powered it down from the menu bar. Ever
  6. Out of curiosity, what are your concerns? I left it up and running for a few hours yesterday and a few hours today and it's still been rock solid. So far the only time things get questionable is when you put a CD in, it appears the screen distorts ever so slightly as the disc is read, but that might be normal? I wonder if the CD drive needs a recap as well, it smells like fish when I eject the caddy out of the drive.
  7. Thanks to your post, I FIXED THE ISSUE! Based on your post I had two theories: A. That filter cap is actually bad and causing the input power to the whole board to be messy. B. That melted looking pot that controls the 5v and 12v outputs is dirty and causing issues on those ends. I was able to turn up my soldering iron heat as high as I could and was able to wiggle the old filter cap out. The bottom of it had a little bit of electrolyte leaked on it which pretty much confirmed to me it was shot. I also hit that pot with deoxit. I wasn
  8. I’m fairly certain the issue is with the flyback. The noise i can hear coming out of the back when it distorts sounds like it is coming from the flyback transformer, although perhaps the issue is being caused by whatever is feeding the transformer. Unfortunately it seems like finding these transformers in 2020 is impossible. I haven’t found one anywhere online. My guess is I’m going to need a working donor board from another LC to fix it.
  9. Well today I replaced all but one capacitor on the analog board. Absolutely no change to the issue. The big filter capacitor was the one I didn’t change out as my soldering iron couldn’t get hot enough to melt the leads, but from what I’ve read online they don’t usually go bad anyways. As i was working i checked again for any cracked solder joints and there’s nothing. There was, however, a potentiometer that looked a little warped (dare I say melted?) in the middle of the analog board. I have no idea what it controls and I don’t have a part number to get a replacement for it,
  10. It’s probably a long shot but do you know if there’s any schematics out there for the LC 520 analog board? It’s a little hard to troubleshoot what’s going where without em. I pulled the analog board out today and started testing capacitors with my ESR meter. Out of the 10 I’ve tested so far only one had an ESR reading that out of spec (and it was significantly out of spec, so maybe that’s part of the issue?). All the others were all in range. There’s 30+ capacitors on the board so I’ve still got a bit to go, but the bad one is definitely getting replaced. I also double
  11. So I did reseat the ram, logic board, and analog board sadly with no luck. I set the brightness as low as it would go and it didn’t change anything (and neither did maxing out the brightness, not sure if that means anything?). Also tried another circuit in the house and no dice with that either Here’s a video of the issue in action. You can see the brightness will max out at random and the picture size is all over the place. I guess that very well could be a capacitor issue. I bought an ESR meter so I’ll see if I can find which ones need to be replaced.
  12. Hi all! I picked up an LC 520 off ebay a few weeks ago. I cleaned and re-capped the motherboard and to my surprise it booted up just fine. However, the screen will flicker and distort as it runs. A couple times it has flickered and gone to black, which made me have to reboot the machine entirely to get it back up. I believe I can hear the hard drive spin down slightly when the screen flickers, which makes me think the issue is power related. I took a look at the analog board and all of the capacitors look visually okay - I don't see any spilled electrolyte or bulging ca
×
×
  • Create New...