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Re: General Stuff(tm)
Posted: 20 May 2024 20:39
by stephen_usher
Took a look at the Macintosh Portable this evening to try to work out what's going wrong and... it's working perfectly. *sigh*
P.S. Spoke too soon. After about 20 minutes it started misbehaving.
Re: General Stuff(tm)
Posted: 21 May 2024 13:49
by stephen_usher
Well, it looks like I can't buy the Mac Portable "hybrid chip" battery power control module in the UK due to the US company not wanting to register with HMRC and doing the UK Government's work for them for no money.
So, looks like the machine is static display from now on.
Re: General Stuff(tm)
Posted: 21 May 2024 14:52
by rubber_jonnie
stephen_usher wrote: 21 May 2024 13:49
Well, it looks like I can't buy the Mac Portable "hybrid chip" battery power control module in the UK due to the US company not wanting to register with HMRC and doing the UK Government's work for them for no money.
So, looks like the machine is static display from now on.
Stupid unavailable hybrid chip...
Re: General Stuff(tm)
Posted: 22 May 2024 21:42
by stephen_usher
There are plans on the way to try to get a batch of the hybrid "chips" over from the 'States via the Netherlands...
Anyway, tonight I took the floppy drive with a ripped out upper head and stripped the disk motor and control board from it and transplanted them into the original "barn find" floppy from the F1 to see if I could get one working drive out of the two of them.
The plus point is that the drive doesn't destroy floppies.
The negative is that it's not reading the floppies properly.
Looks like it's a dead end. Oh well.
Re: General Stuff(tm)
Posted: 23 May 2024 09:26
by stephen_usher
Oh, and I found a design flaw in the drive, which explains why so many have the top head damaged or ripped off.
When you eject the disk the top head is raised only just, as in micrometres, above the metal shield. In fact most of the time as you remove the disk the head slides on top of the shield! This will get worse over time as the thin ridge of plastic which rides on the metal frame will wear down. I added a thin sheet of card under this ridge which raised the top head by about a millimetre, allowing it to properly clear the floppy disk.
Re: General Stuff(tm)
Posted: 23 May 2024 09:56
by rubber_jonnie
stephen_usher wrote: 23 May 2024 09:26
Oh, and I found a design flaw in the drive, which explains why so many have the top head damaged or ripped off.
When you eject the disk the top head is raised only just, as in micrometres, above the metal shield. In fact most of the time as you remove the disk the head slides on top of the shield! This will get worse over time as the thin ridge of plastic which rides on the metal frame will wear down. I added a thin sheet of card under this ridge which raised the top head by about a millimetre, allowing it to properly clear the floppy disk.
Oh wow, that is quite the flaw!!
Re: General Stuff(tm)
Posted: 23 May 2024 21:51
by stephen_usher
It is!
Anyway, a bit more playing tonight. Partially replaced the caps in the power supply and tweaked the settings on the controller board. More bits going down the floppy data line but it's still giving an 08 error.
The problem now is that I don't know if it's the drive or the machine at fault as I've never had this machine working with a known good floppy drive.
Re: General Stuff(tm)
Posted: 24 May 2024 18:08
by stephen_usher
Just checked the machine can read floppies using a Gotek and it can, so it's definitely not the machine and must be the drive.
I think the next thing to do is replace the capacitors on the controller board.
Re: General Stuff(tm)
Posted: 24 May 2024 21:18
by rubber_jonnie
stephen_usher wrote: 24 May 2024 18:08
Just checked the machine can read floppies using a Gotek and it can, so it's definitely not the machine and must be the drive.
I think the next thing to do is replace the capacitors on the controller board.
I hope it's the caps, though it isn't always...
Re: General Stuff(tm)
Posted: 24 May 2024 21:32
by stephen_usher
I know. I can currently see data going down the read line on the floppy connector but whether it's the correct data or all of it is another matter.