Problematic 1050: BOOT ERROR, but after a while it works

[manterola]

This is a Tandom 1050 that looks great outside. But it makes squeaky noises when the motor is engaged. I cleaned best I could, but it still squeaks lot, and the noises keep changing every 30 seconds or more. 

The problem is that I get one boot error, and then it keeps rotating the diskette. If I turn it off and on, change the diskette, or flip it, and keep trying, suddenly it start working.. And it works the whole session. I first though it need to "warm up" so I also tried to leave it alone spinning the disk, and wait for it to start reading, but it did not happen. 

The drive pass all the 1050 diagnostic test of the 1050 atr I load first using respeqt. 

So where I should start?  Capacitors?, zero track sensor?, cleaning/lubricating the motor? 

 

[TGB1718]

Sometimes the squeaking can be the floppy disk, I had a few that did that and I had trouble booting them too,

my problem was due to old disks that had been badly stored and had formed some sort of layer on the disk, this

was causing a lot of friction, so the drive was strugging a bit, with new disks it was fine (also it gummed up the head and pad which also caused friction and noise)

Edited June 14, 2020 by TGB1718
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[_The Doctor__]

Make sure disk and drive head are clean and pad is gently brushed, you can normally turn the pad holder ever so slightly as well

also some disks have their jackets flattened causing the disk to be tight, sliding the disk jackets edge on a hard corner of a desk can restore the jacket envelopes' squared edge shape and loosen the disk. 'MasterTronic' Disks are notorious for this. Try know good clean disk also.

 

I'd lubricate the shafts and bearing with just a drop in close to the motors/steppers and spindle bearing.

 

When completely cold I'd measure voltages.

 

I  the now clean and lubed drive/ including rails... no longer squeaks and boots, super

 

After that, if noise stops and rpm's are steady. Use it a bit... let it get cold again.. does the problem return?

if it does, then I'd change the drive select and see it does the same for all 4 drive ID's

The transistors in the ID selection chip have been know to go bad some times. Might want to check on that. Cleaning the ID select switches have helped also...

[Kyle22]

Does the squeaking sound change or stop if you open the drive door? If so, it's the disk itsself or the top clamping part of the spindle that sits on the hub when you close the door.

 

[manterola]

Thanks for the suggestions so far. Yesterday I opened the case of this 1050 again. The noisy and uneven squeak comes from the top clamping, and it stops if I gently put a bit pressure on the axis,  and the noise is the same no matter the diskette I use.

So I took it apart , it has a spring. I added a bit of lithium lubricant with a cotton swab. It did not work, but maybe I did not apply enough lubricant. 

The thing that I noticed through, but I am not sure, is that this top clamp did not always started at top speed (so I suspect neither the disk, and the bottom part was moving correctly). So now I am starting to believe that there is a belt slipping problem. I re measured the speed and it is actually going a bit slower (more milliseconds than specs). Maybe I am just in the limit and that's why it kind of  unstable operation.

So I guess I will get a new belt, recheck the rotational speed and then adjust it if necessary. And then report back to you guys. 

 

[cwilbar]

The 'top clamping' assembly has a bearing inside.  I have seen these seize or drag.  Making noise, and even affecting the rotation speed of the disk which can cause errors.

 

I usually pull the clip off, take the assembly out, disassemble it down to the bearing, add a drop of oil which seeps into the bearing from near the center, and then work that oil in by rotating the bearing by hand.

 

The ideal situation would be to clean out the old lubrication and relubricate the bearings, but that is non-trivial, and a drop or two of oil cures most of it by softening up the old hardened grease inside.

 

Also check rotation of the drive hub, with the belt off it should spin freely with no drag.  If it does not, it has bearings as well and they will need lubrication.

 

So far I have not had to replace a belt.  The worst belt I had had a small section with some material removed (where it stuck to the driven wheel).  I cleaned off the wheel and turned the belt inside out and it worked great.  I do keep a spare belt though.

 

Good luck getting it up and working.