Hi Donnie,
I found an even better solution, put an AM (455kHz) LC IF filter and a capacitor in place of the ceramic resonator. Mine worked fine, adjustable from 400 to 600 kHz the motor following the in speed.
If you recycle a filter from an old radio, look to it from the bottom, it should have a capacitor build in and connected to two of the mostly five pins. Use those two. Very common are the outer two pins on the side with three pins.
I will do some testing with the floppymeter later on.
Uwe
----- Original Message -----
From: Donnie Barnes
To: Uwe Teetz
Sent: Wednesday, March 08, 2006 3:19 PM
Subject: Re: [fdutils] Need help with weird floppy issue
On 3/8/06, Uwe Teetz <mhteetz(a)aon.at> wrote:
Hi Donnie,
to the motor speed:
the 3 phase syncron motor controller has a ceramic resonator as reference -> nothing to adjust.
Many of my drives here use 492kHz and 491kHz resonator. This slight difference will not help. For testing I removed the resonator and feed to one pin a signal from an extern oscillator with 1V~ output (you have to try which one is the input to the controller) See pic2. I could regulate the motor from half to double speed easily.
You could also try to replace the ceramic resonator wit a 455kHz resonator used as IF filter in AM radio receiver or put one small RC oscillator in to the case. RC oscillator (potentiometer adjustable) samples are plenty in the net.
I've got a pretty crappy (compared to yours) signal generator that may do what I need. If not, I can certainly build an RC oscillator. Looks like you had yours set to sine wave, but I suppose I'll take a peek at the signal off the oscillator on the device with an oscope. I assume I just need to do floppy access on the PC to make it spin, right?
Thanks for the great info!
--Donnie
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Okay, this is an oddball one.
Anyway, I'm into classic arcade video games. A small series of Sega games
used a floppy drive for their game code instead of ROMs. I have one of
these games, and I believe my floppy disk itself has gone bad. Problem is
that they used a strange format setup. It's a standard 3.5" PC floppy drive
in the game and uses standard HD disks.
Supposedly, however, the disk format alternates 256/1024 bytes per sector.
I've even seen where the game I have uses 8K per sector. Now, the image has
been read successfully off of a disk in a PC running windows and Anadisk.
But nobody so far has figured out how to *write* the image. The games are
emulated in MAME, and thus the disk image exists in MAME ROM archives. The
image for this game is 1925120 bytes in size.
So, is it even possible to write that image back to a floppy? If so, how
would one tackle it? I tried following the fdutils docs to create a special
disk device and then using setfdprm to set it to the closest mss type I
could find (1920/1440), but when I told it to dd to that device with a blank
floppy, it hung (well, it was cranking on the drive for 15 minutes, but
never completed and I couldn't kill -9 the dd process until I ejected the
floppy).
Any help would be appreciated.
--Donnie
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Hi Donnie,
to the motor speed:
the 3 phase syncron motor controller has a ceramic resonator as reference -> nothing to adjust.
Many of my drives here use 492kHz and 491kHz resonator. This slight difference will not help. For testing I removed the resonator and feed to one pin a signal from an extern oscillator with 1V~ output (you have to try which one is the input to the controller) See pic2. I could regulate the motor from half to double speed easily.
You could also try to replace the ceramic resonator wit a 455kHz resonator used as IF filter in AM radio receiver or put one small RC oscillator in to the case. RC oscillator (potentiometer adjustable) samples are plenty in the net.
good luck,
Uwe
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