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Myarc FDC V1.6 80 track Eprom


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#1 BeeryMiller OFFLINE  

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Posted Tue Nov 21, 2017 7:26 PM

Seems like I recall the dip switches with the 80 track eprom on the Myarc FDC have specific settings depending upon whether the card is plugged into 40 or 80 track disks.

​Does anyone know whether "On" is 40 track or 80 track?

 

Thanks.

Beery



#2 Schmitzi ONLINE  

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Posted Wed Nov 22, 2017 8:08 AM

Yes, I have the same question, need to know.



#3 Shift838 OFFLINE  

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Posted Thu Nov 23, 2017 1:28 AM

Seems like I recall the dip switches with the 80 track eprom on the Myarc FDC have specific settings depending upon whether the card is plugged into 40 or 80 track disks.

​Does anyone know whether "On" is 40 track or 80 track?

 

Thanks.

Beery

 

On = 80 track.  I have 2 of t hem.  Each dipswitch corresponds to the drive number.

 

For example:

 

#1 in the ON position is DSK1 @ 80 track

#2 in the OFF position is DSK2 @ 40 track

 

and so on...

 

Hope this helps..

 

Also remember if you are using newer 1.44mb floppy drives to achieve the 80 track DS/DD (720k) and using 1.44 mb floppy disks then you will need to use a piece of scotch tape to cover up the HD hole on the disk.

 

Also I have found that some 1.44 mb floppy drives I have had to format in my 3.5 drive I have set to 40 track to SS/SD (90k) before I can format it without errors in my 80 track drives.  It just depends on the disk manufacturer i think.



#4 atrax27407 OFFLINE  

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Posted Thu Nov 23, 2017 7:50 AM

The tape over the density hole in the disk should be at least opaque. Transparent tape won't do the job reliably. If you use some of the older 720K 3.5" drives (I have several) you don't need to worry about the density hole in the disk.



#5 Romko343 OFFLINE  

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Posted Thu Nov 23, 2017 10:45 PM

Seems like I recall the dip switches with the 80 track eprom on the Myarc FDC have specific settings depending upon whether the card is plugged into 40 or 80 track disks.

​Does anyone know whether "On" is 40 track or 80 track?

 

Thanks.

Beery

 

The controller I sold you already is in 80 TRK mode... dip switch already set to 80 track.



#6 OLD CS1 OFFLINE  

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Posted Fri Nov 24, 2017 2:34 AM

FWIW, you should not use 1.44MB disks for 720k format.  That switch not only indicates the lower density to the controller but it also puts the 1.44MB mechanism into a different write mode which uses a lower magnetic coercion which does not set the magnetic domains of high-density media strong enough to survive long-term (or even short-term depending upon the quality of the media.)

 

Real 720k disks are easy enough to find and cheaply.  I have amassed a rather nice stash of my own for use with my remaining 880k Amiga drives and Commodore 1581 drives.

 

Other than that, thank you for answering a question I have never asked.  Now that I know an 80-track mod can produce 720k disks with a 3.5" mechanism, are there any 80-track mods for the SNUG controller?  I would not mind hooking up a 3.5" drive to mine if it can properly use the disk.



#7 Schmitzi ONLINE  

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Posted Fri Nov 24, 2017 4:31 AM

I slightly remember "DD"-Mods for some 3.5"-HD drives (just one soldering point/cable or so)

Have to check that at the weakend :)

Here in Germany a 3.5" DD-drive is 40 Euros or more (if you find one)

And yes, an 80-track-mod for the BwG would be nice, but I never heard about



#8 atrax27407 OFFLINE  

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Posted Fri Nov 24, 2017 6:52 AM

There is not an 80-track mod for the BWG that I know of. Maybe you can contact Harald Glaab.



#9 Romko343 OFFLINE  

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Posted Fri Nov 24, 2017 10:09 AM

Didn't the Corcomp Disk Controller support 2880 sectors ?



#10 --- Ω --- OFFLINE  

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Posted Fri Nov 24, 2017 10:36 AM

Didn't the Corcomp Disk Controller support 2880 sectors ?

 

The CorComp was a DSDD 40 track controller card.  Which only resulted 1440 sectors.  IMHO in today's market the current prices of these 3rd party floppy controller cards are way out of line.  In another thread Arcadeshopper mentioned the 80 TRACK MODIFICATION for the TI FDC, which in my opinion is the most cost effective way to get 1440 sectors on a disk (emulated or real).  Now the CorComp did control up to four drives while the TI-FDC would only do three.  Seriously though, in these modern times with FinalGROM's and other things, very few people really "NEED" 720K drives or the controller for them.



#11 OLD CS1 OFFLINE  

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Posted Fri Nov 24, 2017 11:57 AM

Need is a subjective term.



#12 Romko343 OFFLINE  

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Posted Fri Nov 24, 2017 12:10 PM

 

The CorComp was a DSDD 40 track controller card.  Which only resulted 1440 sectors.  IMHO in today's market the current prices of these 3rd party floppy controller cards are way out of line.  In another thread Arcadeshopper mentioned the 80 TRACK MODIFICATION for the TI FDC, which in my opinion is the most cost effective way to get 1440 sectors on a disk (emulated or real).  Now the CorComp did control up to four drives while the TI-FDC would only do three.  Seriously though, in these modern times with FinalGROM's and other things, very few people really "NEED" 720K drives or the controller for them.

 

Well, because the Myarcs which I have are rare.. I am selling them for like 200-220 a piece.. HFDC is over 300.00 due to the rareness. I am trying to sell off the rest of my rare items. The PGRAM+ card is also high. For some reason I never did like Corcomp's disk controller, though I had one and still have the disk manager for it.


Edited by Romko343, Fri Nov 24, 2017 12:11 PM.


#13 atrax27407 OFFLINE  

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Posted Fri Nov 24, 2017 12:16 PM

I have both the 80-trk mods for the TI FDC as well as the "Guion" mod for the TI FDC that adds a 4th drive and lowercase disk designations. I will look into combining the two (if possible) if there is any interest.


Edited by atrax27407, Fri Nov 24, 2017 12:17 PM.


#14 atrax27407 OFFLINE  

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Posted Fri Nov 24, 2017 2:02 PM

It is NOT possible to combine the two mods. It is an "either/or" situation.



#15 OLD CS1 OFFLINE  

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Posted Fri Nov 24, 2017 7:28 PM

It is NOT possible to combine the two mods. It is an "either/or" situation.

 

A technical break-down of the problem would be interesting.



#16 atrax27407 OFFLINE  

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Posted Fri Nov 24, 2017 7:36 PM

Part of the problem is space. There isn't enough space in the DSR chip(s) to both add a drive, lowercase access, and 80-trk selection all at the same time. Something (or two) would have to be sacrificed.

The other part of the problem is that the source for the BWG controller is not available (and not likely to be released) since it is still a marketable product.



#17 OLD CS1 OFFLINE  

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Posted Fri Nov 24, 2017 8:51 PM

Is lower-case device access really important?  Seems to me that would be the least practical of the three.



#18 Romko343 OFFLINE  

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Posted Fri Nov 24, 2017 10:29 PM

 

The CorComp was a DSDD 40 track controller card.  Which only resulted 1440 sectors.  IMHO in today's market the current prices of these 3rd party floppy controller cards are way out of line.  In another thread Arcadeshopper mentioned the 80 TRACK MODIFICATION for the TI FDC, which in my opinion is the most cost effective way to get 1440 sectors on a disk (emulated or real).  Now the CorComp did control up to four drives while the TI-FDC would only do three.  Seriously though, in these modern times with FinalGROM's and other things, very few people really "NEED" 720K drives or the controller for them.

 

Yes, but the other situation is how to get double-density out of the modded 80 trk TI controller. Technically, there should be a way to get double-density out of a TI controller with 80 trk mod..



#19 OLD CS1 OFFLINE  

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Posted Fri Nov 24, 2017 11:05 PM

 

Yes, but the other situation is how to get double-density out of the modded 80 trk TI controller. Technically, there should be a way to get double-density out of a TI controller with 80 trk mod..

 

Not technically.  DD is not only a different recording format than SD (MFM vs FM) but it also squeezes more data onto a track.



#20 OLD CS1 OFFLINE  

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Posted Sat Nov 25, 2017 2:49 AM

The other part of the problem is that the source for the BWG controller is not available (and not likely to be released) since it is still a marketable product.

 

I really like my BwG and it came to me via a very gracious 99er back when I first got back into things, but to fully utilize a 3.5" drive it may be time to trade it in for an 80 track-capable DSDD controller.



#21 mizapf OFFLINE  

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Posted Sat Nov 25, 2017 2:51 AM

... and DD increases the bit rate from 125 kbit/sec to 250 kbit/sec.




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