Thanks to Modem7 for pointing out Tezza's alignment procedure, to Chuck(G) for the link to the Tandon maintenance manual, to Al Kossow for maintaining it, to Jafir for the solution to the SS SYS problem, which I have also encountered, and to Stone - you are surprised?

Rather than divert the previous thread concerning formatting a SSDD disk I would like to ask a few specific questions about Tandon maintenance, as I have 4 TM100-2 or 2As and one TM100-4 that all have indicated a one problem or another and been replaced with "one that works" in a 5160 or a 5170 or a lowly Kaypro. As my understanding has progressed I have been able to better understand the nature of the issues, which break down into groups: operator error, electrical problem, mechanical problem.

Operator error, - jumpers in the wrong place, missing terminal resistors or resistors where they don't belong, etc. I've asked a lot of questions about that in the past and I think I understand that subject well enough to catch the most egregious.
Electrical problem - on the advice of the majority I now just assume that if it's electrolytic I should replace it, but if caps don't fix it I can't fix it. Given the absence of operator error most of the rest of the electronics are assumed to be bulletproof.
Mechanical problem - cleaning and lubrication top the list. Making sure everything moves freely is the first step. As Chuck points out most alignment issues are really Track0 sensor issues.


Having gone through these Tandons to make sure they are configured properly, they are clean and move freely through the range of motion and that any electrolytics have been replaced, I now face one more issue, common to all. I am using a SuperCard Pro as my drive exerciser. The SCP software has a suite of drive utilities; maximum track test, drive speed test, alignment test and media test. The Tandons pass all these tests except the media test, which writes to T0H0, T0H1, T1H0, T1H1, etc. sequentially, and reports success or failure of the write-read combination. The Tandons all report multiple failures of H1. H0, which I believe is the bottom one, is fixed. H1 is suspended above and has some "wiggle room".

I don't know whether the disk is moving (not securely clamped in place) or the head is moving (not aligned properly) or simply not making good contact with the media surface. I've tried this test with multiple disks and it recurs in the same pattern.

So the question is: Does anyone have a suggestion for how to diagnose further? What to look for? I do have a dual-channel scope and a 5.25 alignment disk and thanks to the above contributors, some idea how to proceed.

Thanks for your replies,