Jump to content

JRotar

68kMLA Supporter
  • Content Count

    34
  • Joined

  • Last visited

About JRotar

Recent Profile Visitors

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

  1. I've recapped several LC TDK power supplies so this might not be exactly the same, but they all clicked when they were turned on with no load. Apparently there's a protection circuit and you're hearing the power supply reset itself as a safety measure. The 10v seems low, but when you test a power supply without a load you can get measurements that are off. I will say though at least it's not way over so I think you should try it in the machine.
  2. This is the startup schematic: macIIcisch.GIF (693×483) (vintageapple.org) Once recapped and cleaned, pay special attention around the logic chips UD13, UB13, UE13. They're all near the power switch. Many times it's best to try to remove them and clean under them or at the very least use some braid and desolder the pins as much as possible and then reflow with some fresh stuff. There's a trace under C10 that I find gets damaged frequently when that cap leaks on it. Areas with bad corrosion I tend to let soak in vinegar and then scrub with a toothbrush followed by a nice rinse w
  3. This forum seems friendly to beginners at least. Plus there's no harm if it helps you figure out how it works, and it certainly will helps others, myself included. It looks really powerful for the price! I was looking at simple high-low probes but this looks so cool that I may have to get it. I'm really curious if you test out the logic chips with this to see if there's any fault on them! Also, this thread on a IIci has some interesting takeaways about the Qx transistors How I resolved my IIci soft power problems (half bong and instant shutdown when switch
  4. Let me know how it works! I've been thinking about getting one but have no idea where to start. That's exactly how I feel about mine too, even when it did chime. Just felt like something wasn't giving it the "go ahead" to continue. I think I need to try that too...and get more ballsy about doing the real trace repairs I need to do
  5. Chimes do come through the headphone jack....I just double checked on my good IIfx. I've seen a few people mainly with IIci and IIcx that removing and resoldering the logic chips fixes it so definitely try to at least remove as much solder and re-do them and see if that helps. I bought cheap Capton tape off Amazon and it really does work: High Temp Tape, ELEGOO 4 Pack Polyimide High Temperature Resistant Tape Multi-Sized Value Bundle 1/8’’, 1/4’’, 1/2’’, 1’’ with Silicone Adhesive for Masking, Soldering etc.: Amazon.com: Industrial & Scientific
  6. I hear ya. I got a cheap hot air station from Amazon to help. Practiced on a bad board...got to the board I was trying to fix (Not the IIfx luckily) and I ripped a couple pads but I was also getting impatient. I find that if I use braid on the pins to remove as much as possible and then add hot air they usually slide right off in like 30 seconds. Edit: Actually you could also try braid on the pins and then just re-solder, especially if there was corrosion around the chips. Could just be a bad connection. Now this sounds really stupid, but it just hit me. The speak
  7. The trace repair at C7, C8 and C9 makes me wonder if there's more damage over there or under anything around there. On mine I tried to solder a larger cap at C9 but messed it up which gave me instant startup...so that's not your problem, but maybe a good idea to reflow the ones you replaced. I replaced C9 with a smaller one and that stopped the instant startup. Have you replaced the radials? My board had leakage from the radials as well around the startup circuit but not by the power supply connector. I still think it might be a good idea to replace UI18 and UJ18 sin
  8. I'm having the same problem...although at first I would get a bong and now I do not since I ended up having much more extensive trace damage than I could see until I put it under a microscope. The areas toned out continuity fine but looking closer and barely scraping there were several very weak traces barely holding on. Mine were D6 to via, D6 to C42, D5 to UJ18. UI18 and UJ18 also had some corroded legs so I suspect that I may need to remove them and clean underneath, and possibly replace them. I had a continuity issue somewhere on pins 1-7 of UI18 possibly - not sure if it was a fluke o
  9. Yeah, true...and cleaning under them would help too
  10. I usually use that site for power supplies but I guess I need to check it for everything now! In the mean time you can try some vinegar on it to see if that helps remove the corrosion. It was looking pretty puffy. But that cluster of caps near all that startup logic is a death sentence so replacing them is probably best but won't hurt to try vinegar to prep the board for new chips too
  11. Glad I'm not the only one! Let us know if that fixes your problem!
  12. Both the IIcx's I've received have had extreme battery damage so you're lucky you got one without a battery! Your pictures just showed me that I have C15 and C16 on backwards! The rounded edge on the silkscreen made me think positive was to the right. And you can clearly see the right side going to the ground plane. That may explain my chimes of death and instant startup
  13. I have some on order now since it seems that's almost everyone's go-to. I was practicing on a battery-ruined board using leftover cap legs but the wire heats up both ends so fast so once you get one side on, then go to the other it pulls the first side off. And then usually when cleaning after it would pop off and then pull even more trace with it (or do that when heating the 2nd side). Not sure if the copper will help with that or if it's just me not being quite that skilled yet. I was doing things like XLR cables, LED tape, single wires here and there, maybe a through-whole cap for sever
  14. Thanks! Very interesting if it is basically the same card but perhaps re-released. I will get those drivers and see how it works!
×
×
  • Create New...