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MacGyver

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  1. Techknight, you were spot on! I removed the SWIM, then I got a good chime and the "grey" RAM test screen. On floppy access it crashed, of course, without the SWIM. So I replaced the SWIM with the one from my donor board and it booted System 6 just fine! Now I got just one Portable M5120 left to fix... This is also a tough one because it has vertical bars on the screen, every 8th vertical line is black, but not always. I remember an old thread where this was a problem on an SE/30 I believe, and it was a tough one... ;)
  2. Hi there Years ago, I finally got hold of a M5126 backlit Portable. It was untouched, never before been worked on. I was not surprised that it didn't boot and only produced a garbled screen, similar to a Simasimac. I removed the caps, cleaned the board thoroughly, soldered new caps. Same thing. The board is as clean as can be, no dull vias visible, no corrosion from cap goo. I gave up back then, couldn't find a good reason why it shoudn't work. Thanks to Corona ;), I rediscovered the Portable and decided to tackle the problem again. I removed all the caps, double-checked every pad, via
  3. Hi, no, the photos aren't from my logic board, and I didn't post them. I believe they've been taken from another thread where there was a question about how to insert the roms correctly, hence the single misplaced ROM. I double-checked the position of the ROMs in the sockets and double-checked the bad ROMs in a known-good Performa 200. No luck, the ROMs are toast. I didn't try to find out which one exactly is dead, as I figured I'd like to replace them both to get the same timing etc., to avoid other problems. Is there any place on the MoBo I could continuity-check the ROM sockets
  4. Hi there, I checked the ROM pins and the sockets, the contacts are fine. It is really one of the ROMs (can't remember which one right now) which is dead. I even tried to warm it up with a hairdryer, no change at all. Is there any service document which shows the ROM pinouts? They seem to be mask programmed ROMs, no erasing window, no "standard" type. I tried googling the numbers, didn't find any information on these ICs. Ah, by the way, it's the logic board version with only two ROMs. I wouldn't mind using a different type of ROM/EPROM/Flash memory with an adaptor socket in betwe
  5. Hey folks, I just received a Classic II with the common "thick vertical bar" problem. So far, so good, same procedure as every year. Wash the logic board thoroughly... Whoops? No Chime, still vertical bars? Okay, let's replace the caps with tantalum ones. What? Still no chime? Grrr! Then I swapped the ROM with the one of a working Performa 200... ka-ching, it chimes and boots fine?!? I tested the suspect ROM in the donator Performa 200... No chime, vertical bars. The frickin' ROMs are dead? I've never seen that one before. Now, how do I obtain new ROMs? Of course they don't
  6. Hi You're not going to have a problem as long as they don't blow up. It seems like they get a tendency to blow up when they're getting old and weak, so they're really time bombs. I haven't seen a single case of a different PRAM battery leaking or blowing up. I'd recommend you to remove them _before_ they blow up, instead of waiting for them to blow up. I don't replace PRAM batteries, I only remove them . To make it clear, I didn't change anything to the mentioned IIci. I haven't even opened it up before it started smoking (while it wasn't even connected to the mains). A
  7. Hi there, over the years, I've seen several cases of 68k Macs with leaking PRAM batteries. Many of them didn't really leak slowly - instead they seemed to have exploded in an impressive way. Spray of corrosive materials seemed to have landed everywhere inside the machine. Then, I began to recognize a pattern: Every single leaked or exploded PRAM battery I found was exactly the same type and manufactured by the same company: Maxell. Here some photos of a Macintosh LC to visualize the problem: I've placed the same type of battery, but still intact, in the last p
  8. Hi, in my opinion, before doing anything else, you should save the contents of the disk to an image using "disk copy 4.2". this can read and store Lisa disks in a safe way. You should then write the images back to blank disks and use the copys. This way nothing can go wrong. To use disk copy 4.2 you can use nearly all vintage macs with a disk drive.
  9. Hi, to be correct, it is a simple and cheap hot air rework tool made by "Aoyue", but does an surprisingly excellent job. I practiced using it with a IIci board which was beyond repair (exploded PRAM battery) and had no problem removing even big PLCC ICs with the included special jets. For the SMD capacitors I use an ordinary small size straight jet which you can see on the photo: I bought it used (maybe once? there was no discoloration of the jets) for 30€ if I remember correctly. As I understand, you can get these new for around 80€ with only 2 or 3 simple jets. Mine came with a
  10. Hey, I just desoldered all the electrolytic caps with a hot air reflow tool. No lifted pads, everything looks good. I'm quite sure that there's no damage to the copper traces and interlayer connections surrounding the caps. The board has been washed and dried twice now, one run with a mild alkaline (?) cleaning agent followed by tap water, second run with isopropanol to draw out any moisture left. I found out that I just ran out of "classic mac recapping tantalums". Then I was about to solder in the tantalum caps I still had in stock from a camcorder repair, when I suddenly noticed th
  11. Hi, thanks for the eBay link, but there's a catch or two. First, I am not from the US area, so I'd have to pay an awful lot of customs additionally to to the already pretty high price for an EPROM, a diskette and a pretty common microcontroller. Second, I contacted Vintage Micros before regarding some other stuff. I was interested in buying various pieces of hardware from them, but there were still some questions open. I also politely asked if they were still offering older versions of MacWorks for my Lisa which don't need the additional PFG hardware in order to work. The answ
  12. Good morning! (8 AM over here) I tried every combination of RAM, RAM sockets etc. that made any sense and also swapped the RAM with known-good modules from a working SE/30. No success. Wally: Sadly, only the CPU is socketed (and the video rom etc. of course). I already thoroughly cleaned all contacts when I washed the board. It seems that there has been minor leakage from various caps (including C7, C8, C9, C10). You can tell by looking at the solder points surrounding the caps, they appear slightly dull. However, there is no serious corrosion and it doesn't look nearly as bad as so
  13. Hi I am searching for the low level formatting kit for the Apple ProFile harddisk. This was a kit which consisted of an EPROM and a 5,25" disk containing testing/certifying software for the Apple /// which initiated the formatting process. I got all the necessary hardware (Apple ///, ProFile interface, Piggyback Z8 processor) but I'm still searching for the software. My Apple Profile slowly died and I need to swap the drive mechanism with a Seagate ST-412 mechanism. All that is left to do is the formatting. EPROM binaries and a disk image would be just fine, I can burn EPROMs mysel
  14. Ah, that's it... I forgot to try bubblegum. The only question is - where should I stick it to? By the way, eggs won't work. The CPU doesn't get hot enough to fry an egg. This trick is reserved for modern CPUs. I fact I'm not even a fan of MacGuyver. Maybe I watched about 5 episodes when I was a kid, but that's it. It was simply the first nickname that came to mind when I registered myself in this forum And there's one more thing (no pun intended)... This is my first thread in this forum and I forgot to introduce myself. I'm from central Germany (please excuse my bad English... ),
  15. Oh, i have to correct myself. I do get CRT heating with the broken logic board, but the high voltage is missing. I also just tried the reset button, which gives me a nice gong everytime I push it. I also get the usual sad mac sound if I push the NMI button directly after pushing the reset button. Does anybody have experience with this kind of fault? Could it still be bad caps and the dishwasher trick just didn't do it this time?
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