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DavidMil

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Everything posted by DavidMil

  1. I'm also in favor of starting a new, "Calling all 850's" type thread. I ran the program on all three of my 850's and all of them are 2CF990B9. Attached is a pic of one of my 850 result screens. One comment about warerat's wonderful program; If you have more than one 850 you'll want to rename the file after each save or it will overwrite the results of each previous save with the info of subsequent saves. Other than that; this is a really great utility! Hats off to warerat! DavidMil
  2. Thank you DrVenkman. Downloaded and ran Altirra 3.1 and it worked beautifully! DavidMil
  3. Someone said that you can load XEX files into an ATR image, but didn't give clear (for beginners) step by step instructions. Can someone point me to a thread that does this? Or has the instructions. Thanks, DavidMil
  4. Any idea what the version level is on the ROM Chip? DavidMil
  5. There is no mention of a power supply or SIO cable. Nor has it apparently been tested in any way. DavidMil
  6. I have several shoe boxes full of floppies. DavidMil
  7. Check out this 1050 I found on Ebay... Description says, "Looks great and comes with one controller." DavidMil
  8. The problem is the stepper motor! I pulled the transport out and plugged it into one of a good 1050. As soon as I turned on the drive the stepper motor started vibrating back and fourth maybe a mm and everything started getting hot! I guess the motor started dying when I first discovered the problem and has now died totally. Anybody know where I can get a MSAF200A91 Sanyo Part # 4Z26 12V DC stepper motor? David
  9. This might be a good candidate for flashjazzcat's easy video upgrade if you still have your 800 pulled apart. It definitely help with my 800 'bleeding' character problem. DavidMil
  10. R When you say 'jack', are you referring to J15? Remember that this drive worked ( well, mostly worked) for awhile when I first tried to use it. Then I could smell the burning and it's been dead ever since. I don't think that removing the EPROM and putting a ROM in there for a few seconds before I remembered the jumpers that needed to be changed would cause this problem. With either chip in the drive it started heating up. When I get the replacements for U2 & U3, I'm going to try turning it on with J15 disconnected. (That's after I ohm out the stepper motor). David
  11. I have an old MeTex multimeter from about 1992 and my 'O' scope is a 40 MHz Kikusui that is about 10 years older than that. I have a logic probe but I've found that the scope is much more reliable and flexible. DavidMil
  12. That is for the sound adjustment for differences in TV tuners to get ride of static sounds. David
  13. There is no way to get to it without removing the big aluminum casting. I suppose you could snip out the resistor and solder the replacement to the existing leads. It's about two inches in front of the right side cartridge socket. Right beside a ferrite bead. David
  14. Ok, here's what I have currently... U2 and U3 were getting so hot that when I wet my finger and touched them the moisture started to bubble. Also U7 (the 6532 chip) was very hot. Placing the 6532 chip in another drive yields a dead drive till the original 6532 chip was reinstalled (but no heat). The controller chip seems to have been damaged too. R56 was also very hot! With those four chips removed nothing gets hot and I'm getting a rock steady 12V and 5V from Q8 and Q7. I've ordered replacements from Best and I've socketed U2 and U3 so I'm going to try replacing the four chips (starting with U2 & 3) and watch to see what happens. Could the stepper motor have a short that's drawing all that current? David
  15. 20 to 39. But there is something very wrong with that CB. Many chips and resistors and the larger electrolytic caps start getting very warm to darn right hot if the power is left on for awhile. I'm going to have to see where all that current is coming from. Maybe a bad vreg. The power supply is good as I've been using it on my 850 for some time. I hope it hasn't damaged anything else. I'll let you know. David
  16. I answered this yesterday but my post seems to have disappeared. Who knows, maybe I forgot to POST it after I finished. I used a large magnifier and a set of 6x glasses and I can barely see that it is a 2793 chip. Since then I found the problem to be in the controller chip. Suspecting that the problem was the EPROM Rev K, I swapped it out first but nothing changed. So I swapped out the controller with a 'new' chip from Best and the drive formats fine except it was is having problems reading disks it didn't write and the other drives have problems reading the disks it formats. I took the rev L chip out and put the rev K back in and it is better but still having problems reading the outer tracks of disks written by other drives. I'm guessing it needs to be realigned now? David
  17. I did the same mod in another of my 800's and the colors are definitely better on it too! It's just a lot of trouble to strip an 800 down to the MB. I don't think I'm going to go through all that trouble for my 800 that I use for programing. David
  18. Unable to help? You've done so much already! You have nothing to be sorry about! Is shipping from all of Europe high now or is it just some countries? Maybe a work around for shipping could be found? DavidMil
  19. Well I have to admit that this mades a very big difference in the intensity of the colors! Such a simple modification and yet it makes a big difference. Now I'll pull apart my other 800's and do this same mod. Thank you flashjazzcat, David
  20. Well, I'd have lost money on this bet... I was sure it was an problem with the transport, but when I switched it with one of my known good 1050's it worked beautifully. And the problem stayed with the printed circuit board. So I pulled the metal housing off and found an Hitachi HN462732G EPROM with a sticker that said, " TANDON REV K". The Controller is a Western Digital WD2733PL-02. I've included a couple of pictures. I'm open to suggestions here? DavidMil
  21. That brings up a good point, Let me swap the drive mechanisms with one of the good drives and see which part the problem follows. Thanks, David
  22. I have three 1050 drives. Two work beautifully and the third one works fine except: It will not format disks with DOS 2.5. It formats fine with MYDOS and the other two drives can read disks that it formats and writes in MYDOS, but it can't format in DOS 2.5. If I format the disk on one of the other drives, I can then read and write to the disk in the third drive without any problems, and both of the good drives can read what the third drive has written without any problems. I also ran the 1050 CPS disk several times through the test loops without any problems. I'm stumped. DavidMil
  23. What a cool thread! Thanks to everyone for posting. DavidMil
  24. My print heads didn't last very long either. Seems the combs/tines are the number one enemy of the print heads. I ordered three print heads for two different 1027's, and slow but sure after some use the print heads got caught in the combs and destroyed. I think that the print heads may have been a bit too soft and allowed the combs to cut into them after some use. One 1027 had a completely new print wheel from Best (it took some time and a lot of cussing to get the wheel off and replaced). DavidMil
  25. This is very nice work! How long have you been 'dinking' with 850's? Seems like I remember MEtalGuy66 saying some time back, that you had completely disassembled and had (possibly) rewritten the 850 ROM?
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