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kbj

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About kbj

  • Rank
    Star Raider
  • Birthday 11/28/1968

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  • Gender
    Male
  • Location
    Scotland
  • Interests
    Computer repair, electronics, coding

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  1. Hey @Nezgar It was a broken FDC chip, bad tacho wire from the motor and I replaced the EPROM too as part of the repair as I wasn't sure of it. Ta, Mark.
  2. Oh well 🙂 They're not easy to come by either.. Thanks for letting me know. Mark.
  3. Hi @skr Thanks for the info! I'll bear that in mind should I get another drive to repair. I did get the drive working in the end - and it turned out that it wasn't the stepper motor in the end - it was the FDC chip and a broken tacho return wire to the spindle motor. Replaced/repaired that and after a bit of calibration the drive was good once more. KbJ
  4. What was it used for in the modem then? Any ideas? Cheers! KbJ
  5. Hey all, I'm trying to find out what this board is: My first thought was a floppy controller - but if that's what it is, for what machine? I've had a search about the WWW but nothing really jumped out.. Cheers, KbJ
  6. Hey @tf_hh Thanks for the great info Jurgen! Turns out that I had 2 issues. I had a broken wire in the motor tacho return (yellow wire) and the calibration was out. Repaired that and then ran the calibration steps again and all was great. Drive is now working a treat! Thanks again everyone - and hopefully this time the drive will go on to work for a long time to come. Cheers, Mark.
  7. Hey @tf_hh, Thanks for that great explanation. Can I just confirm the procedure then? Should I insert a single density disk first, put the TP8/TP9 jumper on, then adjust for 4uS/125khz and then power down and power up everything and then insert a MFM disk and then check to make sure it's measuring 8uS/250KHz - or do I not need to do that at all? I thought that all I needed to do was to power up without a disk in the drive, and adjust for 4uS/125Khz .? Cheers Jurgen, Mark.
  8. Yeah.. I was thinking the same myself but wanted to check that you guys didn't know something I didn't think of - like 'Ahhh, it's a diode or resistor blah..' I'll have a look at the schematics and identify the wire(s) that take the motor pulse back to the mainboard (think it arrives via Q5 or some transistor) and check for pulses there.. I gotta hope that its a break away from the motor closer to the pin header I guess.. Thanks for the insight @_The Doctor__... I'll report back 🙂 Cheers, Mark.
  9. Hey All, Another update again.. So after checking the calibration (and a drive that was working), all values seemed to be in tolerance according to @tf_hh's guide except for the first measurement (on pin 16 of the FDC) - it was flipping between 4/8uS - adjusted it, tested the drive and now it won't read disks or format them. Strangely, I get error 139's and 142's in SpartDOSx now (using my SIDE3 cart). I went back and remeasured Pin16 and all looked fine. I ran the 1050 diagnostic disk and now it gives me motor errors - and when I check the RPM, it just gives me a constant 0 returned although the drive motor is spinning up etc. Another weird thing is that you know when you format a disk, the head moves from track 0 up to the centre of the disk, then steps its way back down to track 0 during the format? Well it now only does half of that - it formats and steps from track 0 to the centre of the disk and at that point the format stops with an error, motor stops spinning and the head doesn't move back to track 0. So... I took a working drive mech from another drive, connected it to this drive's motherboard and all is good... so I'm not thinking that I have either a bad connection somewhere on the plugs/cables or a spindle motor ? What do you guys think before I take this drive outside and drive back and forth over it with my car? 🙂 Cheers, Mark.
  10. Hi @bob1200xl The motherboard is good - I've just repaired it (faulty regulator and one bad ram). It boots to the colour Atari screen and I have a couple of cart games that run fine. I don't need a PSU really - I have a 9Vac supply that works fine with it. I repair all sorts of retro stuff so I'm happy to have a look at a keyboard.. But if you're a dab hand at repairing them, maybe I could pay you to fix and ship? 🙂 I've always wanted a 1200XL, so when this motherboard came up (in the USA, untested for spares) I jumped on it. Really just need the other parts (case and keyboard) to bring her back from the dead and into my collection 🙂 Cheers, Mark.
  11. Hey @Nezgar Ahh, that was a pic from a different test 2732 that also didn't work - final, working one has a new sticker on top 🙂 I have a GQ4x4 and a TL866 II - used the GQ4x4 with an external PSU to do the programming on those 21v EPROMS.. Cheers, Mark.
  12. Hey All, Just an update on this 1050 drive issue. I had another look at the logic board with a scope and noticed that when switching the drive on and off and scoping the address pins on the ROM that sometimes I would see good data for a few seconds and then it all would stall and it looked like the board had crashed I checked the EPROM again in my programmer (read the contents and compared to a known good EPROM) and all looked good. Just in case, I wrote another EPROM with data from the good file and plugged it back in to the board and it worked! Drive is working fine.. Looks like I may have had a couple of bad 2732A EPROMS... (and a WDC/6532) I took the EPROM that I had burned originally and wrote a batch file to continuously read its contents and compare it to the known working ROM dump - and about 2-3 times out of 5 it had errors.. damn! In the end, I replaced the WDC chip, 6532, EPROM, 2 sockets and did a recap but now the drive is working very sweetly! I really can't thank you all enough for helping me troubleshoot this little pig (hehe!) and for the amount of knowledge you've all helped me gain throughout this 🙂 Cheers! Mark.
  13. Hi @bob1200xl Just wondering if you have a case/keyboard that I could purchase from you for a 1200XL? Cheers, Mark.
  14. Hi @bob1200xl, I guess as long as the case is complete I could try a bit of retro brighting? Also, is the keyboard repairable? How much were you thinking? and can you PM me some pics? thanks, Mark.
  15. Hi Bob, Since I only have the motherboard, I was looking to make the 1200XL whole again.. full case and keyboard 🙂 I'm in the UK (Scotland).. Cheers, Mark.
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