This is a copy of a 1050 question posted on the newsnet, and the answer it received. Files transferred by Mark Keates. Edited and tidied by Dean Garraghty.¢And just to fill you in, Ben Poehland had a bit of a fire in his house recently.¢-----------------------------------¢¢Subject: How can I fix my 1050?¢Summary: Do I have a head alignment and/or track 0 sensor problem?¢¢Greetings to all.¢¢I've been having trouble with my 1050 disk drive for some time now, and a few hours ago I had no choice but to open it up to try to fix it myself.¢¢In doing so, I decided to unscrew the track 0 sensor and clean the space between the transmitter and detector (I guess that's all it is).¢¢However, when I was screwing the sensor back in place, I realized that there was more than one position to put it back in. The reason is that the two holes for the screws in the sensor casing are *oval*, which allows for a couple of millimeters of play. Unfortunately, I have no idea how you're supposed to figure out exactly where the right position is!¢¢When I first put the sensor back in place, the drive was unable to read *any* sectors back. Then I slid it over a bit, and thankfully it was able to read some of the sectors near the center of the disk. After playing around with it a bit more, I can get it to read almost the whole disk properly.¢¢When I try to read in a sequence of sectors starting at sector 500 (remember that there are 720 sectors in all, on 40 tracks), I can see the head step toward the center of the disk track by track - until it gets to the end of track 37, when it actually steps *back* by one track (to 36)! Then it fails to read the sector, and the head goes back to track 0 to reorient itself, and it goes out to track 38 as it should. Does anyone have any idea why it does this? What do you do to fix this?¢¢The other thing I'm worried about now is *writing* to disks. While my drive might be able to write sectors (I haven't tried yet), it is likely that no other disk drive will be able to *read* these sectors (except for my drive).¢¢So what I'd like to know is, is a head alignment based solely on the position of the track 0 sensor? Do you need an oscilloscope to 'center' the sensor? Is there hope for someone without an oscilloscope to do this? Any references to technical documents, personal suggestions, helpful hints, or any comments, are welcome (and thanks in advance!).¢¢¢Jean Goulet¢¢¢CC:POEHLAND¢Subj:1050 Drive Alignment¢¢In IA8V91#84 AKH104@PSUVM (sure would like a name there) suggests downloading the 1050 drive diag prog from compuserve & use the software to align the sensor.¢¢I was unaware the software was available online, but I do agree with this suggestion. I had occasion to use the diag program this past weekend (before the fire) & saw that sensor alignment didn't require a scope. You just move the sensor around until it says OK. I've never had occasion to use it, as I always made ascoremark first.¢¢I think it will work, but it's tedious. Mostly because the sensor invariably ends up moving while you're tightening it down If I aligned a sensor that way, I wouldn't trust the drive until it had passed the 10-min burn-in test in the diag prog, plus also had passed compatability tests with at least 2 other known good drives.¢¢The diag program is probably worthless if you only have one drive, & that's the one that needs aligning. You need at least one known good drive to load in the the test program. Then disconnect the good drive & boot up the misaligned one to do the job. If the bad drive is already pretty close to correct alignment you might luck out & be able to load the test software with the bad drive.¢¢I got the diag prog some years ago from B&C. It might also be in the 8bit library on GEnie.¢¢About the time I was fighting the fire in my house Jean Goulet sent me email expressing concern about the drive in question being equippeed with U/S Doubler & noting the drive already had a Tandon mech. (Sorry for the delay, I've been distracted the past few days (!))¢¢I'm not 100% sure of this, but I'll take a stab at it. If your original mech was a Tandon & you replace it with a Tandon, no problem, the U/S-D ROM will work fine. The only thing you need to concern yourself with is the RPM adjustment on the new mech. The RPM.COM utility in SpartaDOS is just fine for this. (I also use the RPM utility in DOS 2.6f, but Sparta's is better.) The RPM adjustment screw is right in front of the area in the rear of the drive where all the connectors plug in, near the 2917 tachometer chip.¢¢*** NEVER *** attempt to adjust ANY of the pots under the RF shield!!!¢¢If the original mech was a WST type, the drive is equipped with U/S-D, & you plug in a replacement Tandon mech, my gut feeling is that it should still work, but since I haven't done it myself I won't swear to it. You'll still need to adjust RPMs on the new mech. The 1050 diag software doesn't work on 1050's containing U/S-D. If you want to run full diags on a U/S-D drive, you have to pull out the ICD chips & replace the original chips. If there was a jumper change when the U/S-D was installed, you have to desolder the jumperts & put them back in their original positions. Fun, fun, fun!¢¢Of course, if you trashed the original chips, or failed to note the originl jumper configuration, you got a hell of a headache.¢¢I was in the process of investigating the ROM/jumper situation the weekend of the fire. Dunno if I'll ever get back to it now.¢¢BEN POEHLAND¢8-BIT EDITOR¢CURRENT NOTES MAGAZINE¢¢**********************************************************************¢
