Jump to content


  • Content Count

  • Joined

  • Last visited

Everything posted by RSwipeCA

  1. Ah that's great info guys. Thanks very much to all of you.
  2. Oh ok that's great info. May I ask what type of drive you recommend? Just a standard every day PC floppy drive?
  3. Hi all. I recently acquired a great condition 520ST setup. It came with a SF354 external floppy drive. The previous owner said there was a problem with the drive, so I opened it up to take a look. The drive responds to a disk when its inserted and tries to spin up, but there is no belt connecting the motor to the disc drive mechanism flywheel. I am guessing that the belt fell off and somebody removed it from the case. What's the chances of getting a replacement belt for this drive? I've searched on the net but it doesn't look too promising. Alternatively, is there another drive that I can put inside the case of this drive, if I cannot get a replacement belt? The drive is a Chinon F-353AT RevA Thanks guys.
  4. Do I really want another one???? Might have been the wine talking. lol.
  5. Well thanks for all your help everyone. I am running with the original SALLY, ANTIC and GTIA chips, go figure!? But, replaced overheating Ram, Capacitors, MMU and socketed everything (Ram removed and replaced twice lol). It's all good! .... Now I need a new broken Atari....... Have a fantastic 2015 everyone!!!!!! Damian.
  6. Yeah! But at least it's good practice swapping them out. Now I have a nice board fully socketed, that makes me sleep better at night.....
  7. Just waiting on my new MMU arriving, then I will post an update. In the mean time..... Merry Christmas everybody, and may you have a safe, prosperous and Happy New Year. Thanks for all your help! Damian.
  8. I forgot!!! I also changed the RAM chips as a couple of them were almost too hot to touch in the beginning. But yes, its looking good! Will keep you posted on the chip swaps guys.
  9. Hey Everyone. Sorry for the delay, I was away AGAIN with work. If we didn't need the money eh???? Anyway, it looks like we've cracked it! I got around to socketing the entire board - good practice with the solder sucker and the iron. I started removing all the chips one by one and putting them into my good 800XL. It turns out that the only chip that 'kills' my good XL is the U3 C061618-16 8434FMM MMU. I put my good C061618-16 into the bad XL and it displays the normal blue screen and READY prompt!! Now, so far I have replaced with new, the U17, U7, and U8 chips. I don't know if this machine is now working because of a combination of the new chips and the good MMU U3 chip from my other machine or not. What I will do is swap back in the old suspect SALLY, ANTIC and GTIA chips one by one and see if it has any effect. I now need to get my hands on a newC061618-16 8434FMM MMU chip. Where would be the best place to get one of those? I have attached two images. The chip 'in socket' is the good one that works in both XL's. The chip placed on the board is the defective one. They have slightly different markings - same C061618 number though. Will I have to find the exact same 'Good' chip? Question, can I use an Epprom burner to 'make' a new MMU? How does all that work? I will keep you posted on the U17,U7,U8 swapping. Thanks again guys. Looks like we brought another XL back from the trash can. Damian.
  10. Thanks Bob. Just got back from business trip. Will look into it and post findings. Ok. Yes Pin 11 on U18 is GREEN LOW LED Pulsing Beep Flashing Orange LED and Pin 12 is RED/GREEN LED Lit Pulsing Beep Flashing Orange LED. Different. I will now begin the process of socketing the remaining chips. I will then check one by one using my working XL. Thanks for your help. Will let you know.
  11. U18 PIN 12 RED/GREEN LED Lit Pulsing Beep Flashing Orange LED - same as CPU 39. U18 PIN 13 RED LED HIGH
  12. U17 PIN 30 is GREEN LOW Pulsing beep Flashing Orange LED Many thanks Bob.
  13. CPU 39 is both RED/GREEN LED Lit plus pulsing beep and flashing Orange LED CPU 40 is RED HIGH ANTIC 29 is GREEN LOW
  14. I now have sockets for all the chips. I am going to start the process of socketing the remaining chips on my board. Should make things a little easier on this 800XL.
  15. Yes, I am using that now thanks. I have just checked all the ram chips. According to SAMS and according to my good XL all the RAM chips U9 to U16 are HI on pin3 when they should be P. Chips U9 and U10 Pin6 should be P but are 0 dead. All the chips on my good XL are as per SAMS Schematic. Chip U2 looks problematic from a probing standpoint Pin4 should be P its 0 Dead. And Pins 10-15 should be P but are all HI no pulse. lol @ "If you're looking for something to replace next". All fun and games.
  16. Ok. First time I have used a logic probe. I attached it to a motherboard ground and to the middle line at the power switch which showed a value of 5.4v. When I probe pin 37 it lights Low and has a pulsing beeper and flashing yellow LED. A Narrow High Pulse? Ah, should I be testing using TTL or CMOS? Under TTL both high/low LED'S illuminate with the same flashing orange and pulsing beeper. I assume that both high/low indicates 50% toggle? I have the SAMS schematic. I have checked all the pins on U8 All are correct EXCEPT for pin #6 should be P but is H No Pulse, pin#7 should be P but is L No Pulse and Pin# 36 should be P is H no pulse. Sorry I am pretty new to this sort of thing, eager to learn the basics at least. I know that I could rapidly be venturing out of my depth.
  17. Ah. What that is is a little dab of red ink from a permanent marker. I dotted all the chips from the suspect XL just in case I got them mixed up with the new ones, or the chips from the good XL. Well spotted though!
  18. Ha. Now you got me thinkin'. The line comes from 'Don't give up' from Peter Gabriel's 'So' album. Just found it on my shelf - had to blow the dust off! But yeah, it's not the point of this discussion. lol. But I understand that a sledgehammer may be looming on this motherboards horizon. Nah, only joking.
  19. Hi Bob. There is no noise, pops of any kind when I power it on. I took the BASIC ROM out and still the same red screen. I adjusted the color pot to go from the blue back to the red screen. I have socketed all the chips marked with blue tape. I retested the XL after each socket installation as I went - no change from red screen. In the image the BASIC ROM is removed but that was also socketed and fitted for testing. I swapped all the chips marked with the blue tape one by one into my socketed spare 800xl. Every one of those chips when placed into the good XL had no ill effect on the good XL. It booted to the 'Ready' prompt every time. When I swapped the chips from the good XL into the bad one they had no effect on it. It still produced a red screen. EXCEPT the two chips in the centre of the mobo ( marked with the red 'x' ) when either or both were swapped from the good XL into the bad one, upon power up the screen just went black. When I swapped those two chips from the bad XL into the good one it still booted to the 'Ready' prompt - Hope that makes sense. So, even with my very limited knowledge of this topic it appears that the socketed chips are functional?? And that something else is going on. If it's supposed to boot to self test without the BASIC ROM then clearly, as it's not, that's an indication of further issues I am guessing. I have a logic probe and good multimeter. I can download the schematics? Is it time to start checking voltages etc? I am running the power supply that boots my good XL. Dumb question - does the keyboard have to be connected for an XL to boot? I just thought that all I have done so far, regarding test reboots, has been done without it attached. As Peter Gabriel once wrote, "Don't give up, you still have friends"........ or was it Kate Bush... .
  20. Hi Guys, Ok, so I received the GTIA, ANTIC and CPU chips that I ordered. I haven't had a lot of time to play yet, but after swapping the CPU no change still just red screen. After swapping ANTIC no change still just red screen. But, after swapping GTIA the screen is now a even blue. But, no 'Ready' prompt. Here's a picture. I think that this particular symptom can indicate missing BASIC ROM?? I have to go out now, but I plan to socket that chip also, and I will risk swapping over this suspect BASIC ROM with that in my other working 800XL. Sound like a plan?
  21. It's nice to know there is at least two of us in the same boat lol. The help I have got so far from the guys here has been invaluable. I will keep plugging away 'till I either hit a brick wall or get it running again. I will do my best to document the proceedings so it can act as at least a path for others to follow - at least as a pointer to a possible fix. My RAM was as hot as you describe, since replacing they at least appear to be running at normal temps. As you can see I still have a few IC's to socket yet, will be completing that over the next few days. Hopefully we will get to a point where we make some headway. But I am sure there are many things that could be wrong, and not necessarily the same thing with both systems. Definitely keep in contact, lets see who succeeds or gives up first lol.
  22. Not the most elegant. But it should do the job.
  23. Yeah guys, this is what I will be tackling next....
  24. Yeah thanks that's good advice. I took my time desoldering the three chips. I used a solder sucker to remove all the solder from the pins on the underside of the board - very time consuming but in the end the chips basically fell away from the board. Cleaned up any stray solder left behind on the board surface with some solder braid and made sure that the pins were aligned before pushing them into the sockets. They went in easy and have a good firm fit. I checked for continuity from the chip pins, through the socket and into the board. They all check out perfect. So, just waiting for the replacement chips to arrive and what adventure that will bring. Incidentally, anyone ever replaced a chip pin/leg? Cut one from a dead chip and soldered onto the 'stump' of a good chips missing leg? I wonder if that is possible.
  • Create New...