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Author Topic: Stepper motor Profile disk acts weird.  (Read 189 times)

mactjaap

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Stepper motor Profile disk acts weird.
« on: June 28, 2021, 06:10:18 pm »

I bought a Profile disk on EBay

Macintosh Apple Profile A9M0005 Lisa 5MB Hard Drive External Parts or Repair
Please check the photos. I suspect the unit has been dropped. The case has a little damage as shown.
Powers on and makes a lot of noise from drives. No power cord.
Sold As-Is Where-Is What-Is


Damage is shown on the pictures and the disk was not tested. As these disk are not often seen in the Netherlands I decided to give it a try. I have one working profile, a second would be nice.



I won the auction at $102.50 and used my US shipping address to send it to because only US shipping was allowed. Last week it arrived and I inspected it. The power unit, board and disk looked OK. So I decided to power it on. As was stated in the add: Powers on and makes a lot of noise from drives.
I know the first thing to look at is the stepper motor. Does it do its startup routine? It did, but not as I expected.
I made a YouTube  movie to show it. The movie is around 3 minutes long. The stepper motor sometimes, sweeps back and forth. And it also pauses. These pause can take as long as 40 seconds. But the stepper motor finish its job and the ready light will turn solid red.

https://www.youtube.com/watch?v=gUxkSGfzfT0

Who knows what is happening here?


Spoiler alert.
The Profile seems to work OK. LOS 3.1 sees the disk and has formatted it. I can copy on and from the disk
« Last Edit: June 28, 2021, 06:12:29 pm by mactjaap »
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stepleton

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Re: Stepper motor Profile disk acts weird.
« Reply #1 on: June 28, 2021, 06:33:56 pm »

I have one that behaves similarly; it has a few bad blocks and always has for the 25 years that I've owned it. I'm guessing yours must have bad blocks too. Each backward sweep may be to visit a spare block that the ProFile is using as a substitute for a bad block, although I haven't read the ProFile ROM disassembly close enough to know for sure.

Use BLU or NeoWidEx to see the count of bad blocks. If LOS 3.1 works, it won't be all that many. If it's 0, I'll be surprised!
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AlexTheCat123

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Re: Stepper motor Profile disk acts weird.
« Reply #2 on: June 28, 2021, 09:19:02 pm »

My ProFile that recently died has a similar (but more severe) behavior and I'm pretty sure this just means that it has some bad blocks.
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patrick

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Re: Stepper motor Profile disk acts weird.
« Reply #3 on: June 29, 2021, 01:36:22 am »

Your drive starts up and recalibrates. The spare table is read, this is the seek at the beginning. Now each block is read and its CRC checked.. You have three spared blocks, these are the seeks to the center (where the replacement blocks reside). Besides that there are a couple of pending bad blocks.  Here it takes significantly more time until the block has been read or timeout occurred. These bad blocks will be replaced by spares in case the next write access fails.
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mactjaap

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Re: Stepper motor Profile disk acts weird.
« Reply #4 on: June 29, 2021, 04:32:04 pm »

Thanks for your help! Nice to know that is familiar behavior.
If I check the disk with BLU  indeed it shows a spare count of 20 and spares allocated 1, but 0 bad blocks.


More news about this disk..... Bonus find:
I see that my new Profile disk has a Z8603 on board. It has 2K ROM. This "Piggyback" ROM is necessary if you want to do a low level format.

Quoted from  Patricks web site:

Quote
When the Z8 microcontroller family was introduced in 1979, Flash memory was not invented yet. Internal memory was mask ROM, and for software development either external EPROM memory or an in-circuit emulator system was used. Zilog offered two different mask ROM controllers, the Z8601 with 2kB and the Z8611 with 4kB ROM. For software development, two special prototyping devices were available, which had an external EPROM sitting on the back of the chip. These "Piggyback" devices were the Z8603 (with 2kB 2716) and Z8613 (with 4kB 2732).

http://john.ccac.rwth-aachen.de:8000/patrick/Z8emu.htm

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mactjaap

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Re: Stepper motor Profile disk acts weird.
« Reply #5 on: June 30, 2021, 05:04:28 pm »

I did find a nice schedule in this document: 072-0116_Profile_Level_II_Service_Manual_Oct84.pdf

http://bitsavers.informatik.uni-stuttgart.de/pdf/apple/disk/profile/072-0116_Profile_Level_II_Service_Manual_Oct84.pdf

It shows how the startup should be. It should not take longer than 90 seconds. I my case it is around 180 minutes, but the drive works so I can live with that.

I installed LOS 3.1 on it. After formatting the disk three bad blocks are seen by NeoWidEx. Before I formatted it  only one. I hope the disk stays OK....
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mactjaap

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Re: Stepper motor Profile disk acts weird.
« Reply #6 on: July 02, 2021, 11:52:17 am »

In this manual I read this:

Quote
When the Pro-File first came out the firmware program  used for the ZS microprocessor on the Controller PCB was  contained on a ROM chip located piggyback on the ZS. After  this version had been out in the field awhile, it was found  that due to the heat expansion that occurred when the machine  was turned on, the leads from the ROM's piggyback socket were  intermittently separating from the z8. 
Since the Z8 would be looking for program instructions when  this happened, the temporarily open input would be  interpreted as a bit in an instruction code and cause the Z8  to do strange things including putting the Pro-File into  Write mode as the heads were doing a seek to a target track.  This of course destroyed any sector header and/or data block  fields that happened to be passing under the heads as they  were on their way to the target track. 

Later when a read of the damaged sectors was tried, either as  a result of the next power up Scan operation, or a read  command from the host computer system, the Z8 would detect  the problem and ultimately spare the sector which of course  made the malfunction look like a media problem. 

The logical solution for the imagined media problem (the Z8  problem was not known at the time) was to replace the now  badly formatted (though undamaged) HOA with a new HOA. This  action would cause the Pro-File to work fine until the  piggyback ROM again separated from the Z8. The HOA would be  replaced again,etc. 
Needless to say this process was not very effective. The  masked ROM Z8 has been developed to be an effective solution  to this problem. All piggyback Z8s are to be replaced with  this version. It is projected that most of the current Pro File problems will be remedied by this upgrade.




Could it be that the Z8 in my newest Profile is the one it is revering too. The serial number is also very low compared to my other Profile with a masked Z8.
Serial number: 101060
There are alo many small differences. Like stickers, on off switch, net cable socket other way around, etc.

- Could Profile with serial number 101060 be a very early Profile?
- Is the Z8 one that can be used for LLF?
- is the Z8 on this Profile one I should replace?
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patrick

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Re: Stepper motor Profile disk acts weird.
« Reply #7 on: July 02, 2021, 01:52:11 pm »

Of course, a Piggyback Z8 is less reliable than a Mask ROM part. You have 24 extra connections that can lead to errors, and the whole thing is heavier and could come loose from the socket during transport. IC sockets and Apple - this is a very special story. It's a good idea to remove each chip from its socket once every ten years or so and put it back in. This will eliminate many problems associated with contact corrosion.


- Is the Z8 one that can be used for LLF?
- is the Z8 on this Profile one I should replace?

Yes, you can use it to format. And if you want, you can upgrade to FW 3.98.

There are not many things that can replace your Z8. If you have a mask ROM version, use that and keep the Z8 for formatting purposes. Otherwise, your only alternatives are the Z8 piggyback or an UB8820M piggyback board.

With 0x1C = 30 used spares you still have two left. You could format your drive (luckily you own a piggyback Z8 ;-) and see what happens. If the bad blocks come back, there is a media error. That could be from a head crash, if the drive was moved while the disk was spinning. If they stay away, they are from loose contacts on the logic board, a weak power supply, or a user in a hurry who turned off their drive before it finished all operations. You can perform low-level formatting as many times as you want, and nothing will break if this process is interrupted in any way. You would just have to start it from the beginning again.
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mactjaap

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Re: Stepper motor Profile disk acts weird.
« Reply #8 on: July 02, 2021, 05:28:46 pm »

Thank you very much for the explanation about LLF.

To be honest I'm a little reluctant to LLF it now. It is still working and I'm afraid that if things go wrong I have a Profile as paperweight...
On the other hand I would also like to try it, it would be great if LLF could make this disk better.
I've been reading about it and I understand that BLU can do this LLF.
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patrick

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Re: Stepper motor Profile disk acts weird.
« Reply #9 on: July 03, 2021, 03:24:53 am »

The process is explained here in detail: http://john.ccac.rwth-aachen.de:8000/patrick/UsbWidExamples.htm.

A formatting tool performs these steps automatically. It doesn't matter if you use Apple's 5M FormatCertify disk for the Apple ///, NeoWidEx or BLU on a Lisa or UsbWidEx standalone controlled by any computer (PC or Mac or anything with RS-232 terminal).
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stepleton

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Re: Stepper motor Profile disk acts weird.
« Reply #10 on: July 03, 2021, 07:23:54 am »

just a note: NeoWidEx only formats Widgets --- it won't work on ProFiles! UsbWidEx, BLU, or something official from Apple are your best choices there.
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mactjaap

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Re: Stepper motor Profile disk acts weird.
« Reply #11 on: July 03, 2021, 09:20:46 am »

just a note: NeoWidEx only formats Widgets --- it won't work on ProFiles! UsbWidEx, BLU, or something official from Apple are your best choices there.

Thanks for this update.
I will wait with the LLF until the disk stops working. For now I can work with it. But.... you gave me an idea...

One of my Widget drives won't work. It has 44 HEX bad blocks ( so...68 DEC) and 4C spares (76 DEC).
I have run NeoWidex 0.4 on it and if I'm lucky i have output. I shall try a LLF on this disk, because I can't use it anyway now.
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