External Apply 5.25 read problem

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Joined: Jun 4 2014
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I was using my beige 5.25 external drive that came with an Apple IIgs. The drive worked fine for many disks but now when I put in any disk I get the disk boot error on the IIgs.

I used a disk cleaner with solution but do not see any difference. Any other suggestions for me to try?

Thank you!

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Joined: Dec 19 2003
Posts: 832
Re: External Apply 5.25 read problem

Two possibilities immediately come to mind. The first one is that the magnetic head is too dirty to successfully clean with a simple kit. To find out how do the head cleaning on a floppy drive, use the AppleFritter search engine to find the previous discussion. The other possibility is that the drive motor needs to have it's speed adjusted. For this you will need a disk utility program like Copy II+ and a different (working) disk drive with which to load it. There is a sub utility on this, and other similar programs, that will tell you if the RPM's of the drive are within the prescribed operating specifications.

speedyG's picture
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Joined: Nov 16 2011
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Re: External Apply 5.25 read problem

bides there is also the chance of misalignment of track zero....
take a view to:
http://www.appleii-box.de/H084_1_AppleIIDiskService1.htm
there are all possible troubles explained by lots of pics and text....
allthough the pages are related to the DISK II there are at some areas also
explenations to drives with other mechanic too..... if you read the entire
explenations you will understand what must examined and how to examine....
all procedures are explained very detailed....
i guess it will help to solve problems also, if for example trouble is caused by other issues...
speedyG

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Joined: Jun 4 2014
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Re: External Apply 5.25 read problem

I took the drive apart, cleaned the head (which is spotless) and made sure connections were tight. Everything looks new and I do not see anything obvious.

Sometimes when I insert a disk it starts to load but then makes very loud noises (maybe 1 second long or so and repeats a few times) then a I get an I/O error.

I'd like to run the CopyII+ utility for the speed test but do not have another drive. I do have the SD Unidisk but could not connect both at the same time.

Argh!?

speedyG's picture
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Re: External Apply 5.25 read problem

That ticking after the startup and start loading - indicates recalibration.....
so the sensor indicating track zero has been moved or partialy damaged and the
drivehead moves out of track after few steps.....
that´s not a question of speed it´s a question of track alignment....

The other possible reason for recalibration is a misalignment of the read/write circuit.
Some drives have trimming resistors for realignment of the read/write compensation,
but this kind of alignment can only be adjusted with supporting use of an oscilloscope
and measuring the signals while performing adjusment ( viewing the bad dirt in signals getting
compensated and "cut off" from signal, while signal itself gets clean and sharpe raising pulses
and clean sharp edges ) as explained in related pages mentioned above.
speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
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Re: External Apply 5.25 read problem

This discussion begs the question, at what point is it worth your time and effort to revive a piece of hardware? They made millions of Apple ]['s and probably twice as many 5.25" floppy disk drives. It shouldn't be that hard to find replacements on the internet for not much money. The problem is the shipping costs. I have a small pile of them I'll probably never use. They do age out as the drive belts get old. But contact corrosion (on the connectors), head dirt, and out of sync. speed issues can all be fairly easily remedied. Over the years I've considered getting an oscilloscope for this and other reasons, but haven't done it, even with the availability of small ones that plug into a computer for their readout. It just isn't worth the time and effort to me.

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Re: External Apply 5.25 read problem

The real effort is the purchase of the oscilloscope if there is not a unit availiable for use or lending....

and of course first time performing such a adjustment task requests more time due to read and
followup of the instructions....

but at second time after getting familiar with the measurementpoints and adjustment procedures things speed up....

in general when you are familiar with the procedures adjustment of track zero requests about 30 minutes
( including time for dismounting and mounting of the drive )
and a readjustment of the read/write compensation request up to maximum of 15 to 20 minutes adding 15 minutes for dismounting and mounting of the drive....

So specially if you have several drives - as you explained - the task is not that much timeeating....

recalibrating a bunch of 10 drives with recalibration of track zero and adjustment of read/write compensation can be performed within one afternoon....

speedyG

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Joined: Jun 4 2014
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Re: External Apply 5.25 read problem

The drive was working perfectly and then suddenly stopped.. I was hoping it was a simple fix but it does not appear to be that way. I hate to throw any old computer part away.

The link that shoes the info about the Disk 2 has a ton of details.. looks quite complicated from what I can tell...

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Re: External Apply 5.25 read problem

eebuckeye wrote:

The link that shoes the info about the Disk 2 has a ton of details.. looks quite complicated from what I can tell...

not that bad....
5 topics = 5 pages
some topics permit 2 or 3 solutions... so each page starts explaining what parts are relevant to the current topic
then the page focusses to each solution path....
the mass of information is due to the mass of different topics and solutions....
if you start reading you recognize it´s neither magic nor that complicated....
the mass of pictures with comments just help to find related part and identify them....
speedyG

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In early days I had a lot of money but no time - now I have no money but a lot of time....
the second part includes less friends but a lot more joy on life....