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About DistantStar001

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    Chopper Commander

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    San Rafael, California

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  1. Theoretically, 9v AC 2.5 Amps. Then why did it drop to 5v? That's just weird. Any idea what king of glue was used? Maybe there's a solvent that won't damage the plastic. Also, in the interim, I do have two 12v (3 Amp) DC supplies for the Vic, and several other 9v AC bricks, but I'm reluctant to use them without knowing the exact power requirements of the drive (how many amps does it pull? and how many volts can it tolerate?). I believe I saw a 7805 in the drive, so I don't think 12v will hurt it, but I'd like some reassurance before I try.
  2. So my PSU for my Atari 1050 floppy drive died (possibly because I was using it to power a VIC-20). Now I have a new 12v DC supply for my VIC, but that still leaves me without a working supply for my Atari floppy. I know I could get a new PSU for the drive (I'm not so sure about using the same 12v supply from my VIC), but if it's possible I'd like to fix the original if possible. I mean for all I know, it could be something simple, like a blown fuse. The only problem is that I have no idea how to get into the thing without damaging the case. Any suggestions? OK, it's not a fuse, since it is putting out about 5.7v with no load.
  3. Found it. A small break in the trace above the 7 key.
  4. I already have two enhanced //e's so I was looking to keep a few original. I was able to narrow part of my problem to the ribbon, as the problem keys mentioned before show up on both keyboards with that particular ribbon. However, now the A, and Z keys don't work on the original board regardless of which ribbon, but do work on the alternative board. Again, I've tested the switches and the traces, and they all seem fine, but the keys won't respond? I also tried tripping the keys with a screwdriver. No luck. The other keys worked (screwdriver or switch). It's just these two keys on this one board? Just tried dome De-Ox-It, no luck.
  5. It's good news bad news time! The good news is that thanks to your help, I was able to trace the problem to the CD and EF ROMs. So my board now works! The bad news is that the replacement ROMs came from one of my other //e's and I'm now 2 ROMs short to use both boards (worse, they're the un-enhanced versions, and there aren't that many replacements that I'm aware of). Still, the board works!!! (if you can't tell I'm really happy about that. And also Thank You!!). Also, this board is more period appropriate to the case I have. The other bad news is that when testing the boards, I found that the 7, =, U, P, K, and , keys on my keyboard had stopped working. I tested the switches with a multimeter and they seemed fine, but neither board will recognize them. I think they might just be dirty, but the 99% IPA isn't cutting it. So I'm wondering what people's thoughts were on the best brands of de-ox-it?
  6. The picture is from before I swapped out the IOU, but doing so made no difference. Also there is no beep when powered or reset.
  7. I've been working on an Apple //e mother board for a while with no luck. It worked when I got it, and all the ICs are socketed. So I tried to use it to diagnose another malfunctioning board. Unfortunately it didn't work, and when I reseated all the original ICs it stopped working all together (no video, no beep). Finally I decided to give it a run through the dishwasher (figured that I couldn't kill a dead board) and now I get 12 horizontal bars across my screen, each 8 pixels tall. This is the most life I've gotten out of this thing in months! So far I've replaced all the RAM on the machine, the MMU, all the ROMs (Video, EF, CD, and Keyboard), as well as the CPU. It's made no difference if the keyboard is plugged in or not, and I haven't been able to trip it into a diagnostic mode. On a lark I popped in a known bad RAM chip and got a series of As and block on the screen. I swopped out another good chip for bad and got Cs instead of As. Then I hit Control-Open Apple-Reset, and that put the Cs back to As. So I know that the computer can react to the keyboard, just not with known good RAM? Any ideas or suggestions?
  8. Sadly no. All I'm getting is a black screen, no flashing, no nothing.
  9. I managed find the bridge. There was a spot on U9 where the trace from pin 5 is really close to the pad on pin 4 with the tiniest bit of solder between the two. I needed a magnifying glass to find it.
  10. I've found what I think is a short between pins 4 and 5 on the RAM, however, I'm having trouble localizing exactly where the short is. The sort reads on all 8 RAM sockets, and my multimeter doesn't have enough resolution to detect any variances in resistance between them. The board is almost completely plucked now with only U6, U16, and U28 remaining (as they are still soldered in), as such I'm relatively certain that the fault isn't in any of the chips. Any ideas on how to locate the short beyond replacing every socket? Really don't have enough to replace them.
  11. The heat and buzzing appears to be localized at the transformer itself. I've been trying not to leave it plugged in when not in use, but in my last test, within about 5 minutes the heat begins to build up when off, and less than 15 seconds when on.
  12. Is it also normal/harmless for it to get warm when powered off?
  13. I just got a Radio Shack Color Computer 2 (16k). The machine is in practically new condition, as the warranty sticker is unbroken. When I plugged it in, it booted to basic without a problem, but also makes a buzzing sound even when the computer is turned off. I've never owned a CoCo before, so I have to ask, is this normal?
  14. I had two good CIAs in another board, now I have one since pin one broke off. But it did test good, so maybe I can solder a new leg on it? In the interim I'm not messing with the CIAs, since they're not needed to boot, or for a dead test. Also, I may have only have one good one left. With or without ROMs or CIAs, I still get a single flash on my dead test, and black screen with no cartridge. I did get a picture of the new garbage screen on the Diagnostic below. I've replaced the RAM repeatedly, and I can't believe that they're all bad.
  15. Ok, good then. I was just going through the 566 pin by pin.
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