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Stepper motor Profile disk acts weird.
mactjaap:
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....
mactjaap:
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.
--- End quote ---
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?
patrick:
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.
--- Quote from: mactjaap on July 02, 2021, 11:52:17 am ---- Is the Z8 one that can be used for LLF?
- is the Z8 on this Profile one I should replace?
--- End quote ---
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.
mactjaap:
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.
patrick:
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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