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HP 4145B boot disk and Murphy's Law

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TerraHertz:
A while ago I bought a HP 4145B semiconductor parameter analyzer. Originally in perfect condition, it came with the essential boot 3.5" floppy, booted and worked. However the machine had been poorly packed and the front frame had three corners dinged in transport. Which was kind of OK, since the result was I got a total refund via a shipping insurance claim.

At that time I didn't yet have the user manual or any blank floppies of the right format. So rather than make multiple copies of the boot disk immediately as would have been wise, I put it aside.

Since then I obtained the manual and some boxes of the correct floppies, but was busy with other stuff so still put off making the backups.

Just recently I bought a very badly damaged 4145B on which the front frame is in perfect condition. It arrived (no shipping damage), and also had a floppy labelled "4145B boot disk" loaded in the drive.

But that machine doesn't power up, and the front keyboard has many broken buttons. The vector display unit, a HP 1345A does work on the bench though!

Anyway I only bought it for spares, starting with the front frame. After swapping that to the first machine, the plan was to make backups of the boot disk.

But now, it doesn't boot! Off either of the disks. With both floppies the machine gives an error, 'not correct format' and makes repeated 'seeking to track zero' clicking sounds.

Hmm... Well I do have a spares machine. I swapped in (loose, just the cable connected) the spare floppy drive. Same result.
Then also swapped in the floppy controller card (just a thought.) No difference.

Great. So BOTH of the floppy disks are corrupted? But one of them was working before...

Another possibility was that both floppy drives have 'old grease' syndrome, with one of them (my first machine) having gone bad since I last used it (about a year.) Conceivable...

So I did a tear down, clean and regrease of the spare machine's floppy drive.  Success! Now the good machine, with that drive and my original boot disk works fine. Phew. But the other disk labelled "4145B boot disk" shows no sign of being what it says it is. Nada, possibly not even formated.

This is the point at which I really, really should have made some backup disks.  But no... I wanted to see if the other drive, the one that I knew used to work, would also come good after cleaning. Gave it the same treatment. All these old floppy drives have the problem of grease going stiff on friction points, and particularly the head positioning lead screw. Result is the head doesn't position accurately. Also typically the floppy doesn't load and unload properly.

After giving that drive the cleaning treatment then cabling it into the good 4145B, what I should have done was stick some other random floppy in it, with the motor spinning. Just to check it didn't do anything bad to my ONE, precious boot floppy.

Did I? No of course not, that would be too sensible. Also I was doing this today a couple of hours after having my last wisdom tooth out (at age 66) so perhaps I wasn't as 'wisdom' as usual. I powered it up and loaded the precious boot disk.

Immediate horrible disk grinding sounds. The machine partially booted, then froze, with the head cycling back and forth around mid disk. I stopped it, pulled out the floppy and had a look at the media surface. Yep, rough in a band on one side. It's kaput.

But it only mangled that one disk. Any other disks I load now, it's fine. Seems when I cleaned the heads on this one I must have left some surface contamination. Which is gone now, having done its job of stuffing my one boot disk.

Bah. This happened just before the local anesthetic wore off, so now I am not very happy at all.

I do plan to eventually install one of the known-to-work floppy disk emulators in the machine. But not yet. I'd rather familiarize with the machine in the original configuration for a while.

So, does anyone in Sydney have a working HP 4145B? And can make a couple of boot floppies? I can come pick them up, to avoid postal delays and other issues with posting floppy disks.


Edit to add: Oh now I realize what I did wrong! I'd opened the operating manual to the page with proceedure to make backups of the boot disk. Had it open right next to the machine. And a pack of new blank floppies next to it. So OF COURSE that was when my one boot floppy would get destroyed.

knudch:
My guess is that it use the old HP "LIF" format which there exist utilities for copy etc. on a "standard" PC with a 3,5" drive

TerraHertz:
It is definitely LIF. And there are ways to create them from images, but those are all painful rabbit holes involving lots of 'PC stuffing around' - setting up a separate machine, installing an old OS, finding 'right' combinations of floppy drives and controllers, iffy results with obscure defects...

I really don't want to do that now. Some other time when I have a week to waste, and better pain tollerance.

Looks like I'll have to buy a properly created floppy online and wait for postage.

Stray Electron:
Terrahertz,

   Unfortunately the problem is even worse than you describe. In some old style HP disk drives the drive lifts the disk before ejecting it and I found out the hard way that sticktion will sometimes cause the drive not to lift the disk quite enough. Frequently one head is still resting on the disk and if you pull the disk out, the plastic frame of the disk will catch on the head and pull it off of the mechanism or irreversibly damage the head's gimbal.  So it's not enough just to test the drives with a scratch disk, you need to remove the drive from the unit and clean it and re-lubricate it and check that it's ejecting properly before using any disk in it or you risk ruining the drive itself.

  FWIW a local scrapper got ahold of a HP 4145B years ago and I did my best to buy it from him but he was convinced that the gold content was worth far more so he spent an entire day tearing it to bits for the gold boards.  IIRC he later told me that he got a whopping $23 for the gold boards.  I couldn't convince him of the stupidity of spending 8+ hours of labor to get $23 of gold scrap!  Everyone that I know of in the scrap business simply loses their mind at the thought of getting GOLD scrap!  I've seen literally tens of tons of good old computers and high quality test equipment get torn down for the gold in it.

0culus:
Terra, sent you a PM. If you can't find someone locally I can definitely make you a boot disk if you're willing to send one to the US.

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