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AwkwardPotato

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Everything posted by AwkwardPotato

  1. AwkwardPotato

    Macintosh Color Classic No Sound After Recap

    It could be the TDA7052A itself that's faulty.
  2. AwkwardPotato

    Macintosh IICX No Video After Recap

    Sometimes SEs and SE/30s (with which the IIcx is closely related) have the issue you describe when the Bourns filters go bad. The IIcx doesn't seem to have the same kind of filter found in the SE/30, although it does have one at RP13 right next to the external floppy port. Maybe that part is causing issues?
  3. AwkwardPotato

    Macintosh IICX No Video After Recap

    That plastic bar isn't stock. It's hard to tell, but it seems that the tabs for some of the SIMM slots have been snapped off, so I'd guess the bar is there to hold the SIMMs in place (and maybe the RAM not being seated correctly because of this is part of the problem).
  4. AwkwardPotato

    Macintosh IICX No Video After Recap

    Check for continuity between C2 and R3, and between R3 and the internal speaker jack. Run patch wires between them if there isn't continuity to fix the sound issue. As for the chimes of death, a good starting point would be to make sure your RAM is good, if possible.
  5. I think the 6360 and 6400 are also Alchemy-based.
  6. AwkwardPotato

    Macintosh Color Classic No Sound After Recap

    Following the traces is probably your best bet since there isn't an analog board schematic to show what's connected where. TDA7052A could possibly be at fault too, it's hard to tell for sure. Just wondering, what are the voltages at pins 1 and 4 of the TDA7052A (not sure what exactly they're supposed to be but it may help)? Also, can you upload a picture of the top and bottom sides of the board around where the TDA7052A is so we can see if anything is obviously damaged?
  7. AwkwardPotato

    Macintosh IICX No Video After Recap

    Not sure about this, but wouldn't you at least get a chime of some sort regardless of if the NuBus controller is good? Are all the voltages from the power supply good?
  8. AwkwardPotato

    Macintosh Color Classic No Sound After Recap

    I'm not very familiar with the Color Classic, but I'm fairly certain amplification is done on the analog board since there's an amplifier IC (TDA7052A) next to where (I believe) the speaker connects.
  9. AwkwardPotato

    Macintosh Color Classic No Sound After Recap

    Probably an issue with the amplifier then, which as far as I can tell is on the analog board. Have you recapped the analog board yet?
  10. AwkwardPotato

    PowerMac 8500 AV Card

    I was recently able to buy my dream PCI PowerMac, the 8500! It works great, although I can't for the life of me figure out how to use the AV Capture Card. My first question: Is the television connected to the composite video output supposed to mirror the monitor attached to the Mac's DB-15 port? Second question: For some reason, instead of starting, Apple Video Player says that the Video Startup 1.7.3 extension needs to be installed and the computer needs to have video capture hardware (both of which are true for this machine). I feel like both of these issues are occurring because I'm missing an extension/driver/etc. although I'm not sure. I'll note that the only changes I've made with this so far are doing a clean install of System 7.5.3 & upgrading Apple Video Player and the Video Startup extension to 1.7.3 (stock Player version bombed while starting). Also, my primary monitor is running at 1024x768 @ 75hz. Thanks!
  11. AwkwardPotato

    Macintosh Color Classic No Sound After Recap

    Have you tried plugging some headphones/powered speakers into the computer and seeing if the sound from them is audible?
  12. AwkwardPotato

    IIsi death chimes after re-cap and then worse

    No problem EDIT: One more thing I should mention is that when the oscillator is installed, make sure the oscillator's metal shell isn't touching the wire.
  13. AwkwardPotato

    IIsi death chimes after re-cap and then worse

    It's hard to tell but I'm not sure those two vias are the ones connected by that trace. I'd use an x-acto knife or something similar to scrape away the soldermask covering the trace, clean with IPA, tin the trace, and solder a wire on each side to jump over the cut. Don't worry about making it look perfect, it'll work just so long as there's a connection. By the way, it seems that the severed trace is also part of the CPU's data bus, which would explain why it's not working correctly.
  14. AwkwardPotato

    IIsi death chimes after re-cap and then worse

    That may actually be the problem: Trace on the bottom is severed, and the two on the top are suspect.
  15. AwkwardPotato

    IIsi death chimes after re-cap and then worse

    Hmm. You mentioned that you broke a leg off the old oscillator; I wonder if it's possible the through-hole for it was damaged too, resulting in loss of the clock signal to some components (unless it was broken off after it was removed from the board in which case disregard this)? Also wondering if given that it worked before recapping, there were traces damaged while it was being worked on, hence causing it to have this issue after recapping. Close-up pictures of the areas around the replaced capacitors might help with spotting such damaged traces.
  16. AwkwardPotato

    IIsi death chimes after re-cap and then worse

    Do you have the original oscillator available to swap in and rule that out as an issue? Pictures of the top & bottom of board might also be helpful for identifying any mistakes.
  17. AwkwardPotato

    SE Dual 800k - Issues with Lower Drive Port

    Sure, that would work fine too; it would be the same electrically.
  18. AwkwardPotato

    LCIII with no sound

    Yeah, if you've got continuity between all those points, I wouldn't be surprised if the sound chip is the problem. Just wanted to make sure it wasn't something else first, since the sound chip is a custom Apple ASIC and it might be difficult to find a replacement for it.
  19. AwkwardPotato

    Macintosh IIfx PRAM battery leak. Any advice?

    My thoughts on this: You're right, the leakage on that board is pretty horrible. I wouldn't write off repairing it as impossible per se, but it certainly won't be easy. IMO, given how rare and expensive working IIfx boards tend to be, it wouldn't hurt to at least try fixing it. It doesn't look like there are too many rotten traces, but I'd expect that there are quite a few. At the very least, components UD16, UF18, the 8530, the reset, interrupt, and power switches, battery holders, possibly the SIMM slot closest to the batteries, and most of the little SMD passives around them will need to be replaced. In other words, given the cost of a new IIfx board, it wouldn't hurt to try fixing it, but definitely don't get your hopes up too high.
  20. AwkwardPotato

    LCIII with no sound

    Glad to hear you got your board back. I'm not sure if there's a way to test the sound chip in software (hopefully somebody else can chime in on this), but here's part of the schematic relevant to the sound circuitry for the LC III: Pin 10 of the chip labelled 'U1' is the sound output for the Mac, while the shape labeled 'B' is the sound output for the IIe card. Since you're getting the IIe sound, I'd assume the traces between the speaker and amplifier (labeled 'U6') are all good. As such, I'd recommend making sure there's continuity between Pin 10 of U1 and C77, between C77 and R36, and between R36 and C74 and R55 and pin 4 of U6. Hopefully that makes some sense
  21. Capacitors have reference designators starting with C, and crystals have reference designators starting with Y.
  22. AwkwardPotato

    LC Fan and Speaker Clicking

    I don't see any more corroded traces, but I do see some crusty vias. Is there continuity between Pin 2 of UG5 and Pin 15 of the EGRET? What about between Pin 20 of UF8 and Pin 4 of the PSU connector?
  23. AwkwardPotato

    LC Fan and Speaker Clicking

    It's certainly possible that one of the missing caps rolling around on the board and shorting things out could've damaged it, but leaked electrolyte typically won't cause permanent electrical damage aside from corrosion, etc. I'm not sure if the caps not being in circuit would cause damage, though.
  24. AwkwardPotato

    LC Fan and Speaker Clicking

    Here's another corroded trace:
  25. AwkwardPotato

    LC Fan and Speaker Clicking

    Scraping the solder mask off the trace near the ROM will work. I'd put a battery in when testing just to be safe (take it out of course when working on the board though).
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