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About Calab

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    Star Raider

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    Vulcan, Alberta, Canada

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  1. Hrm... Neither Digikey.ca nor Mouser.ca have the 74LS02 in stock. That's not helpful at all. I think I'm going to swap my PSU for a Meanwell unit instead of messing with the capacitors. Should be more reliable this way. [edit]Meanwell PSU ordered from Digikey... now we wait[/edit]
  2. Tried the system again this morning. Still not working. I swapped out the 7406 at U26, since I had one on hand, and the system worked great for about 5 minutes... then the issue returned. It's not seeing anything on the ACSI connector again. Next will be swapping the 74LS02 at U21, but I have to order one. I will get caps to do the PSU as well at the same time. I'm also considering the power supply as well. It's original. Getting 4.9v and 11.6v readings on my meter. I just need to find one at a reasonable price that ships to Canada.
  3. Thanks for the diagram. This one is clearer than the one I have. I will check out U21... and I was thinking U26 as well. A 74LS02 and 7406 should be easier to come by than the DMA chip!
  4. Today, my ACSI port stopped working... It was working previously, but today it got flakier and flakier until it just won't see any devices on the ACSI port. I've tried both an external UltraSatan drive as well as a MegaFile 60 hard drive. I do have a diagnostic cartridge and the Hard Disk test and DMA test are failing. I suspect that the C025913-38 (U27) has failed. I'm reading conflicting information that other chips (C100110-001 for example) will or will not work. Can someone tell me what DMA chips are compatible with an Atari Mega ST 2 machine? One item to note is that the floppy drive appears to be working fine. Wouldn't it also have issues if the DMA chip had failed? Also, if anyone has any other testing/troubleshooting that I could use to narrow this down, it would be appreciated!
  5. Thanks for the info folks. Looks like I'll be setting up my drives differently then. I don't want to run the MegaFile very often. I was just hoping to avoid having to unplug/replug cables on the odd occasion that I did want to use it. Does anyone know if a "Y" type cable would work? Middle of the Y plugged into the ST, one arm plugged to the MegaFile and the other to the UltraSatan?
  6. I have a MegaFile 60 and an UltraSatan. Each works find when connected to my Atari Mega ST2. If I connect the MegaFile to the ST and the US to the Megafile and power them both up, they also work fine. If I don't power up the MegaFile, the system doesn't boot as if the US wasn't there. ID0 = UltraSatan slot 1 ID1 = UltraSatan slot 2 ID3 = MegaFile 60 If I have multiple hard drives on the ACSI bus, do the middle devices need to be turned on to see the devices at the end of the bus?
  7. Well, I figured it out... There are two tabs that stick out from the cage. If you tap the tabs back through the slots the cage will slide apart in two pieces. It was pretty simple once I realized where the seam in the cage was.
  8. I've been diagnosing issues on a 1571 disk drive for a while now. At this point it appears to be either a power supply issue, or an issue with the hybrid U7 part in the 1571 drive. Does anyone know where I could obtain a replacement U7 part?
  9. I've been troubleshooting a 1571 drive for a while now and I've pretty much exhausted everything on the mainboard. I'd like to work on the PSU, but it's wrapped in a metal cage and I don't see how it opens, short of cutting it apart. Does anyone know how I can get into the power supply on my 1571 drive?
  10. I have a 1571 floppy drive that is having issues. I've narrowed it down to some of the larger IC's, which are hard to obtain. Does anyone know if this WD part from Mouser will replace the 6502 in the 1571? Any idea if it would work in the C64, etc.? Mouser 65C02
  11. These are the cables and ports that I am using with my 1200XL and Sophia2. You can see that the four analog pins are missing in the cable, and aren't on the monitor connector either. It works great!
  12. #1. Yup... I made sure to save the desktop. #2. When I dragged the folder from A to C it showed me the copy confirmation dialog, but 0 folders and 1 files. I *think* that the floppies I used were MS-DOS formatted. My later folder copies seemed to work OK. I'm going to check that later. #3. I tried control, but some keys on my keyboard are "iffy". I will give it another go. #4. That sucks... I guess I'll just have to live with it. Being a Mega ST2 I don't think I can run TOS newer than 1.04, can I? It wouldn't be much work to burn six EPROMS with an updated TOS. #5. CPX's??? Haven't heard of that. That definitely helps. Thank you!
  13. Good call... It' is TOS 1.04 and no alternate desktop involved.
  14. So, I figured out how to add the D drive... Select another disk icon, then use the Options menu to Install a drive. Other questions still stand though...
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